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  • 1
    Publication Date: 2024-05-28
    Description: Aus den Bleichenbach-Schichten der Wetterau werden folgende Fährtentaxa beschrieben und abgebildet: Saurichnites salamandroides Geinitz, 1861, Saurichnites intermedius Fritsch, 1895, Saurichnites incurvatus Fritsch, 1901, Temnospondylen-Fährte unsicherer systematischer Stellung, cf. Hyloidichnus major (Heyler & Lessertisseur, 1963), Amphisauroides discessus Haubold, 1970, Varanopus microdactylus (Pabst, 1896), Ichniotherium cottae (Pohlig, 1885), Dimetropus leisnerianus (Geinitz, 1863), Gilmo- reichnus kablikae (Geinitz & Deichmüller, 1882), cf. Gilmoreichnus minimus Haubold, 1973, Protritonichnites lacertoides (Geinitz, 1861), Anhomoiichnium orobicum Dozy, 1935, Palmichnus renisus Schmidt, 1959, Laoporus sp. und Jacobiichnus caudifer (Fritsch, 1895). Die Fährtengemeinschaft erlaubt eine Parallelisierung der Bleichenbach-Schichten mit dem oberen Teil der Nahe-Gruppe des Saar-Nahe-Gebietes.
    Description: Abstract: From the Bleichenbach beds of the Wetterau area (lower Permian, SW-Germany) the following ichnotaxa are described and figured: Saurichnites salamandroides Geinitz, 1861, Saurichnites intermedius Fritsch, 1895, Saurichnites incurvatus Fritsch, 1901, temnospondyl-trackway of uncertain systematic range, cf . Hyloidichnus major (Heyler & Lessertisseur, 1963), Amphisauroides discessus Haubold, 1970, Varanopus microdactylus (Pabst, 1896), Ichniotherium cottae (Pohlig, 1885), Dimetropus leisnerianus (Geinitz, 1863), Gilmoreichnus kablikae (Geinitz & Deichmüller, 1882), cf. Gilmoreichnus minimus Haubold, 1973, Protritonichnites lacertoides (Geinitz, 1861), Anhomoiichnium orobicum Dozy, 1935, Palmichnus renisus Schmidt, 1959, Laoporus sp. and Jacobiichnus caudifer (Fritsch, 1895). This trackway-assemblage permits a correlation of the Bleichenbach beds with the upper part of the Nahe Group of the Saar-Nahe Basin.
    Description: 1. Einleitung 2. Vorkommen 3. Terminologie 4. Kurzbeschreibung der Fährten 4.1. Amphibien-Fährten 4.1.1. Saurichnites salamandroides Geinitz, 1861 4.1.2. Saurichnites intermedius Fritsch, 1895 4.1.3. Saurichnites incurvatus Fritsch, 1901 4.1.4. Temnospondylen- Fährte unsicherer systematischer Stellung 4.2. Reptil-Fährten 4.2.1. cf. Hyloidichnus major (Heyler & Lessertisseur, 1963) 4.2.2. Amphisauroides discessus Haubold, 1970 4.2.3. Varanopus microdactylus (Pabst, 1896) 4.2.4. Ichniotherium cottae (Pohlig, 1885) 4.2.5. Dimetropus leisnerianus (Geinitz, 1863) 4.2.6. Gilmoreichnus kablikae (Geinitz & Deichmüller, 1882) 4.2.7. cf. Gilmoreichnus minimus Haubold, 1973 142 4.2.8. Protritonichnites lacertoides (Geinitz, 1861) 4.2.9. Anhomoiichnium orobicum Dozy, 1935 4.2.10. Palmichnus renisus Schmidt, 1959 4.2.11. Laoporussp 4.2.12. Jacobiichnus caudifer (Fritsch, 1895) 5. Fossilinhalt der einzelnen Fundhorizonte 6. Biostratigraphische Auswertung der Fährten 7. Zusammenfassung und Diskussion der Ergebnisse Schriften
    Description: research
    Keywords: ddc:560 ; Hessen ; Rotliegend ; Fährten ; Tetrapoden
    Language: German
    Type: doc-type:article , publishedVersion
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  • 2
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    Landesamt für Geologie und Bergbau Rheinland-Pfalz
    Publication Date: 2024-05-28
    Description: Ob Energiewende, die Gewinnung geothermischer Energie aus dem Boden, der Bau von unterirdischen Stromtrassen oder die Modellierung des Energiehaushalts der Erdoberfläche – die Kenntnisse der physikalisch-thermischen Eigenschaften des oberflächennahen Untergrundes sind von zentraler Bedeutung für zahlreiche Fragestellen der angewandten Bodenkunde. Böden als 3-Phasengemische aus Wasser, Luft und Festsubstanz können erhebliche Unterschiede und Differenzierungen bezüglich der thermischen Eigenschaften aufweisen. Neben dem Wasser- und Lufthaushalt sind Lagerungsdichte, Textur sowie die mineralogische Zusammensetzung entscheidende Einflussfaktoren. Auf Basis dieser Grundlagen wurden von verschiedenen Autoren Modellansätze entwickelt, um thermische Parameter bei unterschiedlichen Feuchtezuständen abzuleiten. Die meisten dieser Ansätze beruhen auf der Auswertung von repräsentativen Bodenproben, die ein möglichst breites Texturspektrum abbilden sollen. Die vorliegende Untersuchung verfolgt einen alternativen Ansatz. Durch Messungen im Routinebetrieb eines bodenphysikalischen Labors wurde ein umfangreicher Datensatz aufgebaut, der Auswertungen nach verschiedenen laboranalytischen sowie boden- und substratsystematischen Aspekten ermöglicht. Auf dieser breiten Datenbasis sollen die thermischen Eigenschaften von Böden bei definierten Randbedingungen noch genauer gefasst werden. Darüber hinaus sollen Grundlagen erarbeitet werden, die es ermöglichen, thermische Kennwerte über die Kenntnis einfacher Feldparameter möglichst präzise abzuschätzen.
    Description: research
    Keywords: ddc:631.436 ; Bodenphysik ; Wärmeleitfähigkeit ; Rheinland-Pfalz
    Language: German
    Type: doc-type:book , publishedVersion
    Format: 56
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  • 3
    Publication Date: 2024-05-28
    Description: Im Spätsommer 1996 wurde in der oberoligozänen Fossillagerstätte Enspel im nordwestlichen Westerwald vom Geologischen Landesamt Rheinland-Pfalz, gemeinsam mit dem Landesamt für Denkmalpflege Rheinland-Pfalz, eine Forschungsbohrung niedergebracht. Die Bohrung erreichte eine Teufe von 256,3 m. Es wurden 2,6 m Basalt, etwa 137 m lakustrine Sedimente und 90 m Vulkaniklastika erbohrt. An deren Basis folgen fragmentierte devonische Sedimentgesteine, die bis zu einer Mächtigkeit von 24,3 m erbohrt wurden. Die Abfolge repräsentiert die Füllung eines komplexen, maarähnlichen Beckens. Der Bohrkern wird in einem interdisziplinären Projekt von verschiedenen Arbeitsgruppen untersucht, um Bau und Genese des ehemaligen Enspelsees zu erforschen.
    Description: Abstract: In late summer 1996 the Geological Survey of Rheinland-Pfalz and the Landesamt für Denkmalpflege Rheinland-Pfalz sank a research core, in the Upper Oligocene Fossillagerstätte Enspel, Northwest-Westerwald-area. The drilling reached a depth of 256.3 m. 2.6 m of basalt, 137 m of lakustrine sediments, 90 m of pyroclastic rocks and 24.3 m of fragmented Devonian sediments were found. This section documents the filling of a complex maarlike basin. The cores are examined in an interdisciplinary research project concerning the genesis and structure of the Enspel lake system.
    Description: research
    Keywords: ddc:554.3 ; Westerwald ; TK 5313 ; Oligozän ; Bohrung
    Language: German
    Type: doc-type:article , publishedVersion
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  • 4
    Publication Date: 2024-05-28
    Description: The global steel sector is responsible for 7% of global greenhouse gas emissions, highlighting the need for significant changes in production practices and the adoption of low-carbon breakthrough technologies to achieve net-zero emissions. This study was conducted to explore positive tipping points at the company level, taking into account socio-political, economic and industry pressures that initiate the tipping process. The study operationalizes tipping points using the Triple Embededdness Framework, which incorporates indicators from the socio-political and economic environment, as well as the industry regime of companies. An analysis is performed of secondary data from four steel companies: BlueScope (Australia), POSCO (South Korea), voestalpine (Austria), and U.S. Steel (USA). The findings indicate that voestalpine is on the verge of reaching a positive tipping point, and POSCO is also on a promising track. In contrast, both BlueScope and U.S. Steel are lagging behind. In the tipping process, national policies play a critical role in expediting the transition to low-carbon steel production for frontrunners, while global climate policy has a greater leverage by influencing producers who operate in a less stringent national policy context. Additionally, the customer demand for low-carbon steel serves as a driving force for innovation and can incentivize steelmakers to produce low-carbon products.
    Language: English
    Type: info:eu-repo/semantics/article
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  • 5
    Publication Date: 2024-05-28
    Description: Increasing interconnectedness, along with the effects of climate change and other global risk drivers, has led to mounting systemic risks in the complex systems that characterize our world. Systemic risks, with their cascading impacts and long-term sustainability concerns, necessitate transformative approaches to manage their effects across system scales and dimensions. To date, however, an “operationalization gap” impedes translating between propositions for transformative change and policy options for addressing systemic risk. Here, we propose combining systemic risk analyses with local approaches, prominently including knowledge co-production, to achieve a more comprehensive understanding of complex systems. This combined approach can support stakeholders in designing transformative risk management and adaptation interventions that balance individual and higher-order interactions, incorporate diverse viewpoints, and thus manage systemic risks and leverage transformation potential more effectively. Furthermore, we suggest that a risk-layering approach can help differentiate, prioritize, and orchestrate these options for incremental and transformative changes.
    Language: English
    Type: info:eu-repo/semantics/article
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  • 6
    Publication Date: 2024-05-28
    Type: Thesis , NonPeerReviewed
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  • 7
    Publication Date: 2024-05-28
    Keywords: Course of study: MSc Climate Physics
    Type: Thesis , NonPeerReviewed
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  • 8
    Publication Date: 2024-05-28
    Description: Nordwest-australische Fluß-" Dünen- und Staubsedimente wurden zwischen 16° - 23°S und 116° - 129°E beprobt und mit Hilfe von Korngrößen-, Grobfraktions-, Tonmineral-, Karbonat- und 14c-Analysen untersucht. Ferner wurden jungquartäre Profile in den Tälern und Flußanschnitten der Pilbara-Region„ der Edgar Ranges und der westlichen Kimberleys aufgenommen. Die Untersuchungen dienten dem Zweck, die Zusammensetzung und den Umfang der Sedimente kennenzulernen, die von NW-Australien in den Indischen Ozean gelangen„ und zwar getrennt für semiaride (-humide) und aride Klimaverhältnisse. Als Hauptergebnisse sind zu nennen: 1) Sedimentabfolgen und 14C-Analysen erlaubten im Raum Pilbara die Unterscheidung von mehreren semiariden und ariden Klimaphasen im Jungpleistozän. Demnach lagerten sich zunächst vor mehr als 33000 J.v.h. lößähnliche Sedimente unter aridem Klima ab. In der Zeit von 33000 J.v.h. bis 19000 J.v.h. waren die Klimaverhältnisse wohl relativ instabil. Dieses dokumentiert sich in mehreren Kalkkonkretionshorizonten„ die sich unter semiaridem Klima bilden konnten, und zwischengelagerten lößähnlichen Sedimenten (Abb. 17). Ab 19000 J.v.h. herrschte arides Klima mit äolischer Sedimentation vor, die, ihrer Herkunftsgebiete im Osten nach zu schließen, vor allem durch ein Passatwind-Regime beherrscht wurde. Die gleichen Winde führten zum Vorpau der ausgedehnten Seifdünenfelder in der Großen Sandwüste. 2) Im Holozän füllten dagegen fluviatile Sedimentwechselfolgen die Dünentäler im Norden der Großen Sandwüste teilweise wieder auf, so z. B. in den Edgar Ranges. Diese Ablagerungen deuten auf eine starke Zunahme der Niederschläge ab spätestens 6000 J.v.h., die mit den sommerlichen Monsunwinden aus dem Nordwesten zusammenhängen dürften. 3) Unter dem rezenten semiariden bis semihumiden Klima beherrscht anscheinend das fluviatile Sedimentationsgeschehen weite Teile des NW-australischen Untersuchungsraumes. Die Flußsedimentzufuhr vom NW-australischen Kontinent zum Indischen Ozean wird vor allem durch den sommerlichen NW-Monsun gesteuert„ was eine starke Periodizität des Transportes zur Folge hat. Eine Trennung der Flußfracht aus dem Pilbara- und Kimberley-Raum wird durch Tonminerale und Korngrößen ermöglicht. In der Tonfraktion aus den W-Kimberleys herrschen frischklastische Minerale wie Illit und· Montmorillonit vor, in der Fracht aus dem Pilbara-Raum dominiert hingegen der Kaolinit. Im Vergleich zur Pilbara-Region bilden wesentlich feinere Modalkorngrößen die Siltfraktion der Flußfracht aus den Kimberleys. Dieses hängt vermutlich mit der Länge und dem Gefälle der Transportwege sowie unter Umständen auch mit der saisonalen Bündelung der Niederschläge zusammen. 4) Bei den fossilen Seifdünen der Großen Sandwüste lassen sich örtliche Beimengungen„ z. B. von detritischem Quarz am Fuß der Edgar Ranges oder von grobkörnigem Quarzmaterial im Bereich der Nord-Pilbaras, in der Zusammensetzung unterscheiden. Diesem zum Teil regionalen Sandtransport steht ein eher großregionaler Ton- (Staub) Transport mit überwiegend Kaolinit und untergeordnet Illit gegenüber. 5) Die Transgressionsweite des holozänen Meeres konnte mit Bohrprofilen in der Großen Claypan am Nordwestrand der Großen Sandwüste anhand von marinen Sedimenten im Untergrund nachgewiesen und auf etwa 50 km bestimmt werden.
    Type: Thesis , NonPeerReviewed
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  • 9
    Publication Date: 2024-05-28
    Description: Persistently high marine temperatures are escalating and threating marine biodiversity. The Baltic Sea, warming faster than other seas, is a good model to study the impact of increasing sea surface temperatures. Zostera marina, a key player in the Baltic ecosystem, faces susceptibility to disturbances, especially under chronic high temperatures. Despite the increasing number of studies on the impact of global warming on seagrasses, little attention has been paid to the role of the holobiont. Using an outdoor benthocosm to replicate near-natural conditions, this study explores the repercussions of persistent warming on the microbiome of Z. marina and its implications for holobiont function. Results show that both seasonal warming and chronic warming, impact Z. marina roots and sediment microbiome. Compared with roots, sediments demonstrate higher diversity and stability throughout the study, but temperature effects manifest earlier in both compartments, possibly linked to premature Z. marina die-offs under chronic warming. Shifts in microbial composition, such as an increase in organic matter-degrading and sulfur-related bacteria, accompany chronic warming. A higher ratio of sulfate-reducing bacteria compared to sulfide oxidizers was found in the warming treatment which may result in the collapse of the seagrasses, due to toxic levels of sulfide. Differentiating predicted pathways for warmest temperatures were related to sulfur and nitrogen cycles, suggest an increase of the microbial metabolism, and possible seagrass protection strategies through the production of isoprene. These structural and compositional variations in the associated microbiome offer early insights into the ecological status of seagrasses. Certain taxa/genes/pathways may serve as markers for specific stresses. Monitoring programs should integrate this aspect to identify early indicators of seagrass health. Understanding microbiome changes under stress is crucial for the use of potential probiotic taxa to mitigate climate change effects. Broader-scale examination of seagrass–microorganism interactions is needed to leverage knowledge on host–microbe interactions in seagrasses.
    Type: Article , PeerReviewed
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  • 10
    Publication Date: 2024-05-28
    Description: The spatial pattern of Antarctic surface air temperature variability on multi–decadal to multi–centennial time scales is poorly known because of the short instrumental records, the relatively small number of high–resolution paleoclimate observations, and biases in climate models. Here, changes in surface air temperature over Antarctica are reconstructed over the past two millennia using data assimilation constrained by different ice core water isotope records in order to identify robust signals. The comparison between previous statistically based temperature reconstructions and simulations covering the full Common Era driven by natural and anthropogenic forcings shows major discrepancies occurring in the period 1–1000 CE over East Antarctica, with the reconstructions displaying a warming over 1–500 CE that is not reproduced by the simulations. This suggests that the trends in the first millennium deduced from the statistically based reconstructions are unlikely to be entirely forced by external forcings. Our reconstructions show the high sensitivity of the 500-year temperature trend in Antarctica and its spatial distribution to selection of the records for the reconstructions, especially during 1–500 CE. A robust cooling over Antarctica during 501–1000 CE has been obtained in three data assimilation–based reconstructions with a larger magnitude in the WAIS than elsewhere over Antarctica, in agreement with previous estimates with the larger changes than simulated in climate models. The reconstructions for atmospheric circulation indicate that the pattern of temperature changes over 501–1000 CE is related to the positive trend of Southern Annular Mode and a deepening of Amundsen Sea Low. This confirms the role of internal variability in the temperature trends on multi–centennial scales.
    Type: Article , PeerReviewed
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  • 11
    Publication Date: 2024-05-28
    Description: Until now, proxy records have been the primary tool for quantitative reconstructions of the physical world of the ancient and late antique Mediterranean. This chapter demonstrates the combined use of proxy datasets and the hitherto underutilized potential of earth system models in the scientific and historical study of past environmental variations and impacts on human societies. Results from model simulations are able to explain hydroclimatic anomalies observed in the proxy records and provide links to relevant mechanisms. The Late Roman Dry Period and the Late Roman Wet Period of the mid-fourth to early eighth centuries AD are each associated with the increase in the frequency of subsistence crises and with the accelerated infrastructural adaptations of communities and agricultural expansion, respectively. The chapter concludes with an examination of the historical and climatic contexts behind one such anomaly, a subsistence crisis in Cappadocia in the late 300s AD.
    Type: Book chapter , NonPeerReviewed
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  • 12
    Publication Date: 2024-05-28
    Description: The evolution of the northern hemispheric climate during the last glacial period was beset by quasi-episodic iceberg discharge events from the Laurentide ice sheet, known as Heinrich events (HEs). The paleo record places most HEs into the cold stadial of the Dansgaard-Oeschger cycle. However, not every Dansgaard-Oeschger cycle is associated with a HE, revealing a complex interplay between the two modes of glacial variability. Here, using a coupled ice sheet-solid earth model, we introduce a mechanism that explains the synchronicity of HEs and Dansgaard-Oeschger cycles. Unlike earlier studies, our mechanism does not require a trigger during the stadial. Instead, the atmospheric warming signal during the interstadial of the Dansgaard-Oeschger cycle causes enhanced ice stream thickening that leads to the HE during the late interstadial. We demonstrate that this mechanism reproduces the key HE characteristics and provides an explanation for synchronous HEs from different regions of the Laurentide ice sheet.
    Type: Article , PeerReviewed
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  • 13
    Publication Date: 2024-05-28
    Description: There has been extensive research into the nonlinear responses of the Earth system to astronomical forcing during the last glacial cycle. However, the speed and spatial geometry of ice sheet expansion to its largest extent at the Last Glacial Maximum 21 thousand years ago remains uncertain. Here we use an Earth system model with interactive ice sheets to show that distinct initial North American (Laurentide) ice sheets at 38 thousand years ago converge towards a configuration consistent with the Last Glacial Maximum due to feedbacks between atmospheric circulation and ice sheet geometry. Notably, ice advance speed and spatial pattern in our model are controlled by the amount of summer snowfall, which is dependent on moisture transport pathways from the North Atlantic warm pool linked to ice sheet geometry. The consequence of increased summer snowfall on the surface mass balance of the ice sheet is not only the direct increase in accumulation but the indirect reduction in melt through the snow/ice–albedo feedback. These feedbacks provide an effective mechanism for ice growth for a range of initial ice sheet states and may explain the rapid North American ice volume increase during the last ice age and potentially driving growth during previous glacial periods.
    Type: Article , PeerReviewed
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  • 14
    Publication Date: 2024-05-28
    Description: Several large-scale cryosphere elements such as the Arctic summer sea ice, the mountain glaciers, the Greenland and West Antarctic Ice Sheet have changed substantially during the last century due to anthropogenic global warming. However, the impacts of their possible future disintegration on global mean temperature (GMT) and climate feedbacks have not yet been comprehensively evaluated. Here, we quantify this response using an Earth system model of intermediate complexity. Overall, we find a median additional global warming of 0.43 °C (interquartile range: 0.39−0.46 °C) at a CO 2 concentration of 400 ppm. Most of this response (55%) is caused by albedo changes, but lapse rate together with water vapour (30%) and cloud feedbacks (15%) also contribute significantly. While a decay of the ice sheets would occur on centennial to millennial time scales, the Arctic might become ice-free during summer within the 21st century. Our findings imply an additional increase of the GMT on intermediate to long time scales.
    Type: Article , PeerReviewed
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  • 15
    Publication Date: 2024-05-28
    Type: Article , PeerReviewed
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  • 16
    Publication Date: 2024-05-28
    Description: 1. The expansion of scientific image data holds great promise to quantify individuals, size distributions and traits. Computer vision tools are especially powerful to automate data mining of images and thus have been applied widely across studies in aquatic and terrestrial ecology. Yet marine benthic communities, especially infauna, remain understudied despite their dominance of marine biomass, biodiversity and playing critical roles in ecosystem functioning. 2. Here, we disaggregated infauna from sediment cores taken throughout the spring transition (April-June) from a near-natural mesocosm setup under experimental warming (Ambient, +1.5 degrees C, +3.0 degrees C). Numerically abundant mudsnails were imaged in batches under stereomicroscopy, from which we automatically counted and sized individuals using a superpixel-based segmentation algorithm. Our segmentation approach was based on clustering superpixels, which naturally partition images by low-level properties (e.g., colour, shape and edges) and allow instance-based segmentation to extract all individuals from each image. 3. We demonstrate high accuracy and precision for counting and sizing individuals, through a procedure that is robust to the number of individuals per image (5-65) and to size ranges spanning an order of magnitude (〈750 mu m to 7.4 mm). The segmentation routine provided at least a fivefold increase in efficiency compared with manual measurements. Scaling this approach to a larger dataset tallied 〉40k individuals and revealed overall growth in response to springtime warming. 4. We illustrate that image processing and segmentation workflows can be built upon existing open-access R packages, underlining the potential for wider adoption of computer vision tools among ecologists. The image-based approach also generated reproducible data products that, alongside our scripts, we have made freely available. This work reinforces the need for next-generation monitoring of benthic communities, especially infauna, which can display differential responses to average warming.
    Type: Article , PeerReviewed , info:eu-repo/semantics/article
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  • 17
    Publication Date: 2024-05-28
    Description: In this paper we describe the implementation of the carbon isotopes 13C and 14C (radiocarbon) into the marine biogeochemistry model REcoM3. The implementation is tested in long-term equilibrium simulations where REcoM3 is coupled with the ocean general circulation model FESOM2.1, applying a low-resolution configuration and idealized climate forcing. Focusing on the carbon-isotopic composition of dissolved inorganic carbon (δ13CDIC and Δ14CDIC), our model results are largely consistent with reconstructions for the pre-anthropogenic period. Our simulations also exhibit discrepancies, e.g. in upwelling regions and the interior of the North Pacific. Some of these differences are due to the limitations of our ocean circulation model setup, which results in a rather shallow meridional overturning circulation. We additionally study the accuracy of two simplified modelling approaches for dissolved inorganic 14C, which are faster (15 % and about a factor of five, respectively) than the complete consideration of the marine radiocarbon cycle. The accuracy of both simplified approaches is better than 5 %, which should be sufficient for most studies of Δ14CDIC.
    Type: Article , PeerReviewed
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  • 18
    Publication Date: 2024-05-28
    Description: Global coupled climate models are in continuous need for evaluation against independent observations to reveal systematic model deficits and uncertainties. Changes in terrestrial water storage (TWS) as measured by satellite gravimetry missions GRACE and GRACE-FO provide valuable information on wetting and drying trends over the continents. Challenges arising from a comparison of observed and modelled water storage trends are related to gravity observations including non-water related variations such as, for example, glacial isostatic adjustment (GIA). Therefore, correcting secular changes in the Earth's gravity field caused by ongoing GIA is important for the monitoring of long-term changes in terrestrial water from GRACE in particular in former ice-covered regions. By utilizing a new ensemble of 56 individual realizations of GIA signals based on perturbations of mantle viscosities and ice history, we find that many of those alternative GIA corrections change the direction of GRACE-derived water storage trends, for example, from gaining mass into drying conditions, in particular in Eastern Canada. The change in the sign of the TWS trends subsequently impacts the conclusions drawn from using GRACE as observational basis for the evaluation of climate models as it influences the dis-/agreement between observed and modelled wetting/drying trends. A modified GIA correction, a combined GRACE/GRACE-FO data record extending over two decades, and a new generation of climate model experiments leads to substantially larger continental areas where wetting/drying trends currently observed by satellite missions coincide with long-term predictions obtained from climate model experiments.
    Type: Article , PeerReviewed
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  • 19
    Publication Date: 2024-05-28
    Description: Enhancing ocean productivity by artificial upwelling is evaluated as a nature-based solution for food security and climate change mitigation. Fish production is intended through diatom-based plankton food webs as these are assumed to be short and efficient. However, our findings from mesocosm experiments on artificial upwelling in the oligotrophic ocean disagree with this classical food web model. Here, diatoms did not reduce trophic length and instead impaired the transfer of primary production to crustacean grazers and small pelagic fish. The diatom-driven decrease in trophic efficiency was likely mediated by changes in nutritional value for the copepod grazers. Whilst diatoms benefitted the availability of essential fatty acids, they also caused unfavorable elemental compositions via high carbon-to-nitrogen ratios (i.e. low protein content) to which the grazers were unable to adapt. This nutritional imbalance for grazers was most pronounced in systems optimized for CO 2 uptake through carbon-to-nitrogen ratios well beyond Redfield. A simultaneous enhancement of fisheries production and carbon sequestration via artificial upwelling may thus be difficult to achieve given their opposing stoichiometric constraints. Our study suggest that food quality can be more critical than quantity to maximize food web productivity during shorter-term fertilization of the oligotrophic ocean.
    Type: Article , PeerReviewed , info:eu-repo/semantics/article
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  • 20
    Publication Date: 2024-05-28
    Description: Laboratory experiments showed that the isotopic fractionation of δ13C and of δ18O during calcite formation of planktic foraminifera are species-specific functions of ambient CO concentration. This effect became known as the carbonate ion effect (CIE), whose role for the interpretation of marine sediment data will be investigated here in an in-depth analysis of the 13C cycle. For this investigation, we constructed new 160 kyr long mono-specific stacks of changes in both δ13C and δ18O from either the planktic foraminifera Globigerinoides ruber (rub) or Trilobatus sacculifer (sac) from 112 and 40 marine records, respectively, from the wider tropics (latitudes below 38°). Both mono-specific time series Δ(δ13Crub) and Δ(δ13Csac) are very similar to each other, and a linear regression through a scatter plot of both data sets has a slope of ∼ 0.99 – although the laboratory-based CIE for both species differs by a factor of nearly 2, implying that they should record distinctly different changes in δ13C, if we accept that the carbonate ion concentration changes on glacial–interglacial timescales. For a deeper understanding of the 13C cycle, we use the Solid Earth version of the Box model of the Isotopic Carbon cYCLE (BICYLE-SE) to calculate how surface-ocean CO should have varied over time in order to be able to calculate the potential offsets which would by caused by the CIE quantified in culture experiments. Our simulations are forced with atmospheric reconstructions of CO2 and δ13CO2 derived from ice cores to obtain a carbon cycle which should at least at the surface ocean be as close as possible to expected conditions and which in the deep ocean largely agrees with the carbon isotope ratio of dissolved inorganic carbon (DIC), δ13CDIC, as reconstructed from benthic foraminifera. We find that both Δ(δ13Crub) and Δ(δ13Csac) agree better with changes in simulated δ13CDIC when ignoring the CIE than those time series which were corrected for the CIE. The combination of data- and model-based evidence for the lack of a role for the CIE in Δ(δ13Crub) and Δ(δ13Csac) suggests that the CIE as measured in laboratory experiments is not directly transferable to the interpretation of marine sediment records. The much smaller CIE-to-glacial–interglacial-signal ratio in foraminifera δ18O, when compared to δ13C, prevents us from drawing robust conclusions on the role of the CIE in δ18O as recorded in the hard shells of both species. However, theories propose that the CIE in both δ13C and δ18O depends on the pH in the surrounding water, suggesting that the CIE should be detectable in neither or both of the isotopes. Whether this lack of role of the CIE in the interpretation of planktic paleo-data is a general feature or is restricted to the two species investigated here needs to be checked with further data from other planktic foraminiferal species.
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  • 21
    Publication Date: 2024-05-28
    Description: An increasing number of climate model simulations is becoming available for the transition from the Last Glacial Maximum to the Holocene. Assessing the simulations' reliability requires benchmarking against environmental proxy records. To date, no established method exists to compare these two data sources in space and time over a period with changing background conditions. Here, we develop a new algorithm to rank simulations according to their deviation from reconstructed magnitudes and temporal patterns of orbital and millennial-scale temperature variations. The use of proxy forward modeling allows for accounting for non-climatic processes that affect the temperature reconstructions. It further avoids the need to reconstruct gridded fields or regional mean temperature time series from sparse and uncertain proxy data. First, we test the reliability and robustness of our algorithm in idealized experiments with prescribed deglacial temperature histories. We quantify the influence of limited temporal resolution, chronological uncertainties, and non-climatic processes by constructing noisy pseudo-proxies. While model–data comparison results become less reliable with increasing uncertainties, we find that the algorithm discriminates well between simulations under realistic non-climatic noise levels. To obtain reliable and robust rankings, we advise spatial averaging of the results for individual proxy records. Second, we demonstrate our method by quantifying the deviations between an ensemble of transient deglacial simulations and a global compilation of sea surface temperature reconstructions. The ranking of the simulations differs substantially between the considered regions and timescales, which suggests that optimizing for agreement with the temporal patterns of a small set of proxies might be insufficient for capturing the spatial structure of the deglacial temperature variability. We attribute the diversity in the rankings to more regionally confined temperature variations in reconstructions than in simulations, which could be the result of uncertainties in boundary conditions, shortcomings in models, or regionally varying characteristics of reconstructions such as recording seasons and depths. Future work towards disentangling these potential reasons can leverage the flexible design of our algorithm and its demonstrated ability to identify varying levels of model–data agreement. Additionally, the algorithm can be applied to variables like oxygen isotopes and climate transitions such as the penultimate deglaciation and the last glacial inception.
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  • 22
    Publication Date: 2024-05-28
    Description: Oxygen isotopes in biogenic silica (δ18OBSi) from lake sediments allow for quantitative reconstruction of past hydroclimate and proxy-model comparison in terrestrial environments. The signals of individual records have been attributed to different factors, such as air temperature (Tair), atmospheric circulation patterns, hydrological changes, and lake evaporation. While every lake has its own local set of drivers of δ18O variability, here we explore the extent to which regional or even global signals emerge from a series of paleoenvironmental records. This study provides a comprehensive compilation and combined statistical evaluation of the existing lake sediment δ18OBSi records, largely missing in other summary publications (i.e. PAGES network). For this purpose, we have identified and compiled 71 down-core records published to date and complemented these datasets with additional lake basin parameters (e.g. lake water residence time and catchment size) to best characterize the signal properties. Records feature widely different temporal coverage and resolution, ranging from decadal-scale records covering the past 150 years to records with multi-millennial-scale resolution spanning glacial–interglacial cycles. The best coverage in number of records (N = 37) and data points (N = 2112) is available for Northern Hemispheric (NH) extratropical regions throughout the Holocene (roughly corresponding to Marine Isotope Stage 1; MIS 1). To address the different variabilities and temporal offsets, records were brought to a common temporal resolution by binning and subsequently filtered for hydrologically open lakes with lake water residence times 〈 100 years. For mid- to high-latitude (〉 45° N) lakes, we find common δ18OBSi patterns among the lake records during both the Holocene and Common Era (CE). These include maxima and minima corresponding to known climate episodes, such as the Holocene Thermal Maximum (HTM), Neoglacial Cooling, Medieval Climate Anomaly (MCA) and the Little Ice Age (LIA). These patterns are in line with long-term air temperature changes supported by previously published climate reconstructions from other archives, as well as Holocene summer insolation changes. In conclusion, oxygen isotope records from NH extratropical lake sediments feature a common climate signal at centennial (for CE) and millennial (for Holocene) timescales despite stemming from different lakes in different geographic locations and hence constitute a valuable proxy for past climate reconstructions.
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  • 23
    Publication Date: 2024-05-28
    Description: We present transient simulations of the last glacial inception using the Earth system model CLIMBER-X with dynamic vegetation, interactive ice sheets, and visco-elastic solid Earth responses. The simulations are initialized at the middle of the Eemian interglacial (125 kiloyears before present, ka) and run until 100 ka, driven by prescribed changes in Earth's orbital parameters and greenhouse gas concentrations from ice core data. CLIMBER-X simulates a rapid increase in Northern Hemisphere ice sheet area through MIS5d, with ice sheets expanding over northern North America and Scandinavia, in broad agreement with proxy reconstructions. While most of the increase in ice sheet area occurs over a relatively short period between 119 and 117 ka, the larger part of the increase in ice volume occurs afterwards with an almost constant ice sheet extent. We show that the vegetation feedback plays a fundamental role in controlling the ice sheet expansion during the last glacial inception. In particular, with prescribed present-day vegetation the model simulates a global sea level drop of only ∼ 20 m, compared with the ∼ 35 m decrease in sea level with dynamic vegetation response. The ice sheet and carbon cycle feedbacks play only a minor role during the ice sheet expansion phase prior to ∼ 115 ka but are important in limiting the deglaciation during the following phase characterized by increasing summer insolation. The model results are sensitive to climate model biases and to the parameterization of snow albedo, while they show only a weak dependence on changes in the ice sheet model resolution and the acceleration factor used to speed up the climate component. Overall, our simulations confirm and refine previous results showing that climate–vegetation–cryosphere feedbacks play a fundamental role in the transition from interglacial to glacial states characterizing Quaternary glacial cycles.
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  • 24
    Publication Date: 2024-05-28
    Description: Climate change is threatening marine ecosystems on a global scale but particularly so in the Arctic. As a result of warming, species are shifting their distributions, altering marine communities and predator-prey interactions. This is known as the Atlantification of the Arctic. Warming may favor short-lived, opportunistic species such as cephalopods, marine mollusks that previously have been hypothesized to be winners in an ocean of change. To detect temporal regional trends in biodiversity, long-term annual surveys in hotspots of climate change are an unparalleled source of data. Here, we use 18 years of annual bottom trawl data (2005–2022) to analyse cephalopods in the western Barents Sea. More specifically, our research goals are to assess temporal trends in cephalopod fauna composition, abundance and biomass, and to relate these trends to climate change in the western Barents Sea. Main changes in cephalopod diversity and distribution occurred in mid-2000s and early 2010s, which corresponds with a period of warming in the Arctic since the late 1990s/early 2000s. Repeated increased occurrence of the boreal-subtropical cephalopods was recorded from 2005–2013 to 2014–2022. Moreover, the abundance of cephalopods in the area (in general and for most taxa) increased from 2005–2013 to 2014–2022. These observations suggest that the cephalopod community of the Barents Sea is subjected to Atlantification since the 2005–2013 period. This corresponds with previously reported evidence of the Atlantification in fishes and benthic invertebrates in the Barents Sea and benthic invertebrates. ‘Typical’ Arctic cephalopod species such as Bathypolypus spp., Gonatus fabricii and Rossia spp., however, are still much more abundant in the western Barents Sea compared to the deep-sea and the boreal-subtropical species. We also found indirect indications for body-size reduction in Bathypolypus spp. from 2005–2013 to 2014–2022. Overall, the temporal trends in the Barents Sea cephalopod fauna provide evidence for changing marine communities in the Arctic.
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  • 25
    Publication Date: 2024-05-28
    Description: The Cabo Verde Archipelago is related to a mantle plume located close to the rotational pole of the African Plate. It consists of islands and seamounts arranged in a horseshoe‐shaped pattern open to the west, thus forming two volcanic chains, each with a weak east‐west age progression. High‐resolution swath bathymetry of 12 Cabo Verde seamounts is used here to assign each seamount to its pre‐shield, shield or post‐shield evolutionary stage, respectively. The eastern seamounts exhibit degraded and partially eroded morphologies, and are mainly in their post‐shield stage. A new 40 Ar‐ 39 Ar date for Senghor Seamount at 14.872 ± 0.027 Ma supports old ages for the eastern seamounts. The western seamounts generally exhibit younger volcanic‐edifice‐construction morphologies, showing fresh effusive and explosive volcanics, including rarely observed deep‐water explosive volcanism in the Charles Darwin Volcanic Field. Furthermore, the two previously unknown seamounts Sodade and Tavares in the westernmost termini of both volcanic chains exhibit pristine volcanic morphologies, in agreement with present‐day volcanism and seismic activity recorded from the western seamounts. The islands and seamounts rest on three submarine platforms to the east, northwest and southwest, respectively. Taken together, the seamount and island data suggest a shift in igneous activity from the eastern to the other platforms at about 8–6 Ma. However, the complex evolution pattern for both volcanic chains includes the simultaneous occurrence of pre‐shield or shield edifices at any time, followed by erosional and rejuvenation stages. The new seamount data still demonstrate ongoing westward submarine‐growth in both volcanic chains. Plain Language Summary The Cabo Verde volcanic islands and seamounts are located in the central Atlantic Ocean, ∼570 km off the west coast of Africa. They form a horseshoe‐shaped archipelago with two volcanic chains, which were formed by the African plate moving very slowly over a mantle hotspot (the Cabo Verde Plume). Both the northern and southern volcanic chains show weak east‐to‐west age progressions from ∼26 million years to the present day. This study uses underwater topographic data and observations/rock sampling via remotely operated vehicles from 12 submarine volcanic seamounts, including two previously unknown seamounts, collected during four research cruises in the Cabo Verde Archipelago. Geomorphology is used to classify each seamount as being in its pre‐shield, shield or post‐shield evolutionary stage, respectively. Cabo Verde islands and seamounts rest on three submarine morphological platforms, reflecting westward jumps of the main igneous activity, and also confirming the westward migration of the Cabo Verde hotspot beneath both volcanic chains. Key Points We present bathymetrical maps of 12, in part previously uncharted Cabo Verde seamounts Geomorphology reflects various evolutionary seamount stages and relative ages. Four older seamounts indicate late Quaternary sea level lowstands Islands and seamounts rest on three morphological platforms, indicating westward jumps of the main igneous activity
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  • 26
    Publication Date: 2024-05-28
    Description: Arabian Sea upwelling in the past has been generally studied based on the sediment records. We apply two earth system models and analyze the simulated water vertical velocity to investigate coastal upwelling in the western Arabian Sea over the last millennium. In addition, two models with slightly different configurations are also employed to study the upwelling in the 21st century under the strongest and the weakest greenhouse gas emission scenarios. With a negative long-term trend caused by the orbital forcing of the models, the upwelling over the last millennium is found to be closely correlated with the sea surface temperature, the Indian summer Monsoon and the sediment records. The future upwelling under the Representative Concentration Pathway (RCP) 8.5 scenario reveals a negative trend, in contrast with the positive trend displayed by the upwelling favorable along-shore winds. Therefore, it is likely that other factors, like water stratification in the upper ocean layers caused by the stronger surface warming, overrides the effect from the upwelling favorable wind. No significant trend is found for the upwelling under the RCP2.6 scenario, which is likely due to a compensation between the opposing effects of the increase in upwelling favorable winds and the water stratification.
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  • 27
    Publication Date: 2024-05-28
    Description: We investigate the effects of solar forcing on the North Atlantic (NA) summer climate, in climate simulations with Earth System Models (ESMs), over the preindustrial past millennium (AD 850–1849). We use one simulation and a four-member ensemble performed with the MPI-ESM-P and CESM-LME models, respectively, forced only by low-scaling variations in Total Solar Irradiance (TSI). We apply linear methods (correlation and regression) and composite analysis to estimate the NA surface and tropospheric climatic responses to decadal solar variability. Linear methods in the CESM ensemble indicate a weak summer response in sea-level pressure (SLP) and 500-hPa geopotential height to TSI, with decreased values over Greenland and increased values over the NA subtropics. Composite analysis indicates that, during high-TSI periods, SLP decreases over eastern Canada and the geopotential height at 500-hPa increases over the subtropical NA. The possible summer response of SSTs is overlapped by model internal variability. Therefore, for low-scaling TSI changes, state-of-the-art ESMs disagree on the NA surface climatic effect of solar forcing indicated by proxy-based studies during the preindustrial millennium. The analysis of control simulations indicates that, in all climatic variables studied, spurious patterns of apparent solar response may arise from the analysis of single model simulations.
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  • 28
    Publication Date: 2024-05-28
    Description: The glacial–interglacial cycles of the Quaternary exhibit 41 kyr periodicity before the Mid-Pleistocene Transition (MPT) around 1.2–0.8 Myr ago and ∼ 100 kyr periodicity after that. From the viewpoint of dynamical systems, proposed mechanisms generating these periodicities are broadly divided into two types: (i) nonlinear forced responses of a mono- or multi-stable climate system to the astronomical forcing or (ii) synchronization of internal self-sustained oscillations to the astronomical forcing. In this study, we investigate the dynamics of glacial cycles simulated by the Earth system model of intermediate complexity CLIMBER-2 with a fully interactive carbon cycle, which reproduces the MPT under gradual changes in volcanic-CO2 degassing and regolith cover. We report that, in this model, the dominant frequency of glacial cycles is set in line with the principle of synchronization. It is found that the model exhibits self-sustained oscillations in the absence of astronomical forcing. Before the MPT, glacial cycles synchronize to the 41 kyr obliquity cycles because the self-sustained oscillations have periodicity relatively close to 41 kyr. After the MPT the timescale of internal oscillations becomes too long to follow every 41 kyr obliquity cycle, and the oscillations synchronize to the 100 kyr eccentricity cycles that modulate the amplitude of climatic precession. The latter synchronization occurs with the help of the 41 kyr obliquity forcing, which enables some terminations and glaciations to occur robustly at their right timing. We term this phenomenon vibration-enhanced synchronization because of its similarity to the noise-enhanced synchronization known in nonlinear science. While we interpret the dominant periodicities of glacial cycles as the result of synchronization of internal self-sustained oscillations to the astronomical forcing, the Quaternary glacial cycles show facets of both synchronization and forced response.
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  • 29
    Publication Date: 2024-05-28
    Description: Mineral dust is one of the most abundant atmospheric aerosol species and has various far-reaching effects on the climate system and adverse impacts on air quality. Satellite observations can provide spatio-temporal information on dust emission and transport pathways. However, satellite observations of dust plumes are frequently obscured by clouds. We use a method based on established, machine-learning-based image in-painting techniques to restore the spatial extent of dust plumes for the first time. We train an artificial neural net (ANN) on modern reanalysis data paired with satellite-derived cloud masks. The trained ANN is applied to cloud-masked, gray-scaled images, which were derived from false color images indicating elevated dust plumes in bright magenta. The images were obtained from the Spinning Enhanced Visible and Infrared Imager instrument onboard the Meteosat Second Generation satellite. We find up to 15% of summertime observations in West Africa and 10% of summertime observations in Nubia by satellite images miss dust plumes due to cloud cover. We use the new dust-plume data to demonstrate a novel approach for validating spatial patterns of the operational forecasts provided by the World Meteorological Organization Dust Regional Center in Barcelona. The comparison elucidates often similar dust plume patterns in the forecasts and the satellite-based reconstruction, but once trained, the reconstruction is computationally inexpensive. Our proposed reconstruction provides a new opportunity for validating dust aerosol transport in numerical weather models and Earth system models. It can be adapted to other aerosol species and trace gases. Key Points: - We present the first fast reconstruction of cloud-obscured Saharan dust plumes through novel machine learning applied to satellite images - The reconstruction algorithm utilizes partial convolutions to restore cloud-induced gaps in gray-scaled Meteosat Second Generation-Spinning Enhanced Visible and Infrared Imager Dust RGB images - World Meteorological Organization dust forecasts for North Africa mostly agree with the satellite-based reconstruction of the dust plume extent
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  • 30
    Publication Date: 2024-05-28
    Description: Weather causes extremes in photovoltaic and wind power production. Here we present a comprehensive climatology of anomalies in photovoltaic and wind power production associated with weather patterns in Europe considering the 2019 and potential 2050 installations, and hourly to ten-day events. To that end, we performed kilometer-scale numerical simulations of hourly power production for 23 years and paired the output with a weather classification which allows a detailed assessment of weather-driven spatio-temporal production anomalies. Our results highlight the dependency of low-power production events on the installed capacities and the event duration. South-shifted Westerlies (Anticyclonic South-Easterlies) are associated with the lowest hourly (ten-day) extremes for the 2050 (both) installations. Regional power production anomalies can differ from the ones in the European mean. Our findings suggest that weather patterns can serve as indicators for expected photovoltaic and wind power production anomalies and may be useful for early warnings in the energy sector.
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  • 31
    Publication Date: 2024-05-28
    Description: The cold Last Glacial Maximum, around 20,000 years ago, provides a useful test case for evaluating whether climate models can simulate climate states distinct from the present. However, because of the indirect and uncertain nature of reconstructions of past environmental variables such as sea surface temperature, such evaluation remains ambiguous. Instead, here we evaluate simulations of Last Glacial Maximum climate by relying on the fundamental macroecological principle of decreasing community similarity with increasing thermal distance. Our analysis of planktonic foraminifera species assemblages from 647 sites reveals that the similarity-decay pattern that we obtain when the simulated ice age seawater temperatures are confronted with species assemblages from that time differs from the modern. This inconsistency between the modern temperature dependence of plankton species turnover and the simulations arises because the simulations show globally rather uniform cooling for the Last Glacial Maximum, whereas the species assemblages indicate stronger cooling in the subpolar North Atlantic. The implied steeper thermal gradient in the North Atlantic is more consistent with climate model simulations with a reduced Atlantic meridional overturning circulation. Our approach demonstrates that macroecology can be used to robustly diagnose simulations of past climate and highlights the challenge of correctly resolving the spatial imprint of global change in climate models.
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  • 32
    Publication Date: 2024-05-28
    Description: It has long been believed that climate shifts during the last 2 million years had a pivotal role in the evolution of our genus Homo 1–3 . However, given the limited number of representative palaeo-climate datasets from regions of anthropological interest, it has remained challenging to quantify this linkage. Here, we use an unprecedented transient Pleistocene coupled general circulation model simulation in combination with an extensive compilation of fossil and archaeological records to study the spatiotemporal habitat suitability for five hominin species over the past 2 million years. We show that astronomically forced changes in temperature, rainfall and terrestrial net primary production had a major impact on the observed distributions of these species. During the Early Pleistocene, hominins settled primarily in environments with weak orbital-scale climate variability. This behaviour changed substantially after the mid-Pleistocene transition, when archaic humans became global wanderers who adapted to a wide range of spatial climatic gradients. Analysis of the simulated hominin habitat overlap from approximately 300–400 thousand years ago further suggests that antiphased climate disruptions in southern Africa and Eurasia contributed to the evolutionary transformation of Homo heidelbergensis populations into Homo sapiens and Neanderthals, respectively. Our robust numerical simulations of climate-induced habitat changes provide a framework to test hypotheses on our human origin.
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  • 33
    Publication Date: 2024-05-28
    Description: The recurrence plot and the recurrence quantification analysis (RQA) are well-established methods for the analysis of data from complex systems. They provide important insights into the nature of the dynamics, periodicity, regime changes, and many more. These methods are used in different fields of research, such as finance, engineering, life, and earth science. To use them, the data have usually to be uniformly sampled, posing difficulties in investigations that provide non-uniformly sampled data, as typical in medical data (e.g., heart-beat based measurements), paleoclimate archives (such as sediment cores or stalagmites), or astrophysics (supernova or pulsar observations). One frequently used solution is interpolation to generate uniform time series. However, this preprocessing step can introduce bias to the RQA measures, particularly those that rely on the diagonal or vertical line structure in the recurrence plot. Using prototypical model systems, we systematically analyze differences in the RQA measure average diagonal line length for data with different sampling and interpolation. For real data, we show that the course of this measure strongly depends on the choice of the sampling rate for interpolation. Furthermore, we suggest a correction scheme, which is capable of correcting the bias introduced by the prepossessing step if the interpolation ratio is an integer.
    Language: English
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  • 34
    Publication Date: 2024-05-28
    Description: We present a modular framework for generating synthetic power grids that consider the heterogeneity of real power grid dynamics but remain simple and tractable. This enables the generation of large sets of synthetic grids for a wide range of applications. For the first time, our synthetic model also includes the major drivers of fluctuations on short-time scales and a set of validators that ensure the resulting system dynamics are plausible. The synthetic grids generated are robust and show good synchronization under all evaluated scenarios, as should be expected for realistic power grids. A software package that includes an efficient Julia implementation of the framework is released as a companion to the paper.
    Language: English
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  • 35
    Publication Date: 2024-05-28
    Description: To mitigate climate change, the share of renewable energies in power production needs to be increased. Renewables introduce new challenges to power grids regarding the dynamic stability due to decentralization, reduced inertia, and volatility in production. Since dynamic stability simulations are intractable and exceedingly expensive for large grids, graph neural networks (GNNs) are a promising method to reduce the computational effort of analyzing the dynamic stability of power grids. As a testbed for GNN models, we generate new, large datasets of dynamic stability of synthetic power grids and provide them as an open-source resource to the research community. We find that GNNs are surprisingly effective at predicting the highly non-linear targets from topological information only. For the first time, performance that is suitable for practical use cases is achieved. Furthermore, we demonstrate the ability of these models to accurately identify particular vulnerable nodes in power grids, so-called troublemakers. Last, we find that GNNs trained on small grids generate accurate predictions on a large synthetic model of the Texan power grid, which illustrates the potential for real-world applications.
    Language: English
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  • 36
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    Potsdam Institute for Climate Impact Research
    Publication Date: 2024-05-28
    Language: English
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  • 37
    Publication Date: 2024-05-27
    Description: Extreme rainfall generated by storms and atmospheric instability causes innumerable damage to coastal areas and their marine ecosystems. This chapter describes some of the processes that generate critical precipitation events in coastal areas. Among these, the typical synoptic conditions combine with the increase in sea surface temperature and air temperature, coastal geomorphology, and sea breeze. Coastal and regional rainfall events should be studied to understand the meteorological, oceanographic, and geomorphological conditions that cause the extreme events, to later relate them with the consequences on coasts. The effects of the interaction of storms with tides originating storm surges and the effect of sea-level rise are described as well as the main consequences of extreme rainfall events such as beach erosion, decrease in water quality, changes in plankton and fish species that inhabit coastal waters, among others.
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  • 38
    Publication Date: 2024-05-27
    Description: The crises of climate change and biodiversity loss are interlinked and must be addressed jointly. A proposed solution for reducing reliance on fossil fuels, and thus mitigating climate change, is the transition from conventional combustion-engine to electric vehicles. This transition currently requires additional mineral resources, such as nickel and cobalt used in car batteries, presently obtained from land-based mines. Most options to meet this demand are associated with some biodiversity loss. One proposal is to mine the deep seabed, a vast, relatively pristine and mostly unexplored region of our planet. Few comparisons of environmental impacts of solely expanding land-based mining versus extending mining to the deep seabed for the additional resources exist and for biodiversity only qualitative. Here, we present a framework that facilitates a holistic comparison of relative ecosystem impacts by mining, using empirical data from relevant environmental metrics. This framework (Environmental Impact Wheel) includes a suite of physicochemical and biological components, rather than a few selected metrics, surrogates, or proxies. It is modified from the “recovery wheel” presented in the International Standards for the Practice of Ecological Restoration to address impacts rather than recovery. The wheel includes six attributes (physical condition, community composition, structural diversity, ecosystem function, external exchanges and absence of threats). Each has 3–5 sub attributes, in turn measured with several indicators. The framework includes five steps: (1) identifying geographic scope; (2) identifying relevant spatiotemporal scales; (3) selecting relevant indicators for each sub-attribute; (4) aggregating changes in indicators to scores; and (5) generating Environmental Impact Wheels for targeted comparisons. To move forward comparisons of land-based with deep seabed mining, thresholds of the indicators that reflect the range in severity of environmental impacts are needed. Indicators should be based on clearly articulated environmental goals, with objectives and targets that are specific, measurable, achievable, relevant, and time bound.
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  • 39
    Publication Date: 2024-05-27
    Description: August 14 – August 17, 2023, Kiel (Germany) – Kiel (Germany) CAU pherPraO
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  • 40
    Publication Date: 2024-05-27
    Description: Phytoplankton form the base of the marine food web by transforming CO2 into organic carbon via photosynthesis. Despite the importance of phytoplankton for marine ecosystems and global carbon cycling, projections of phytoplankton biomass in response to climate change differ strongly across Earth system models, illustrating uncertainty in our understanding of the underlying processes. Differences are especially large in the Southern Ocean, a region that is notoriously difficult to represent in models. Here, we argue that total (depth-integrated) phytoplankton biomass in the Southern Ocean is projected to largely remain unchanged under climate change by the Coupled Model Intercomparison Project Phase 6 (CMIP6) multi-model ensemble because of a shifting balance of bottom-up and top-down processes driven by a shoaling mixed-layer depth. A shallower mixed layer is projected on average to improve growth conditions, consequently weaken bottom-up control, and confine phytoplankton closer to the surface. An increase in the phytoplankton concentration promotes zooplankton grazing efficiency, thus intensifying top-down control. However, large differences across the model ensemble exist, with some models simulating a decrease in surface phytoplankton concentrations. To reduce uncertainties in projections of surface phytoplankton concentrations, we employ an emergent constraint approach using the observed sensitivity of surface chlorophyll concentration, taken as an observable proxy for phytoplankton, to seasonal changes in the mixed-layer depth as an indicator for future changes in surface phytoplankton concentrations. The emergent constraint reduces uncertainties in surface phytoplankton concentration projections by around one-third and increases confidence that surface phytoplankton concentrations will indeed rise due to shoaling mixed layers under global warming, thus favouring intensified top-down control. Overall, our results suggest that while changes in bottom-up conditions stimulate enhanced growth, intensified top-down control opposes an increase in phytoplankton and becomes increasingly important for the phytoplankton response to climate change in the Southern Ocean.
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  • 41
    Publication Date: 2024-05-27
    Description: Bericht zum Fachworkshop des Forschungsverbundes GEOSTOR der Forschungsmission CDRmare am 11. Oktober 2023 im Geozentrum Hannover
    Type: Report , NonPeerReviewed
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  • 42
    Publication Date: 2024-05-24
    Description: Social-ecological transformation has become an important concept in the face of profound planetary crises (loss of biodiversity, climate crisis). Recently, the needs for social scientific transformation research have become more clearly defined. We reflect on the role of the social sciences and the humanities in democratically shaping social transformation in interaction with other sectors of society. Finally, we sketch three examples that illustrate the kind of new methodological and institutional approaches to be pursued.
    Language: English
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  • 43
    Publication Date: 2024-05-24
    Description: Some forty years ago, the UN Convention on the Law of the Sea 1982 (UNCLOS) created an unusual regime for states to collectively manage common natural resources on the international seabed beyond national jurisdiction (known as the Area) through the International Seabed Authority (ISA). In the intervening years, scientists have increasingly been warning about the serious environmental risks of mining seabed minerals. At this pivotal point in time, when states are negotiating whether or not to allow seabed mining, this essay explores the risk of undermining by mining, that is, contravening international marine environmental law and the obligations and responsibilities of states thereunder by allowing commercial mining activities to commence. We argue that allowing seabed mining in the Area at this juncture, when so much about the deep ocean remains unknown, would risk frustrating a host of measures, achievements, and progress to enhance marine environmental protection, particularly in areas beyond national jurisdiction. We begin with an overview of the ISA and its work to date, before discussing potential interactions between seabed mining and marine environmental law and policies, with a particular focus on the new ocean biodiversity agreement. We conclude by urging states to take cognizance of their overarching duty to protect and preserve the marine environment and ensure that all decisions taken with respect to seabed mining are consistent with their obligations and responsibilities under international law.
    Language: English
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  • 44
    Publication Date: 2024-05-24
    Description: Real-world laboratories have become a recognised research format for addressing sustainability challenges. In these transdisciplinary settings, actors from civil society, local government, and academia work together using a transdisciplinary research approach to jointly experiment and learn about sustainability transformations. While these labs are considered to have potential, their impact has not yet been fully measured. Therefore, in our paper we explore the case of the Zukunftsstadt Lüneburg 2030+ process to uncover the impacts that this long-term effort has generated over the past eight years. By examining the process and its design features from three analytical perspectives, we identify emergent impacts in three dimensions: education, governance, and the lab as an actor for sustainability. Based on our case study, we suggest that real-world labs contribute to sustainability on a local level, beyond the intentional experiments, through impacts that emerge over the course of the joint operation of the lab.
    Language: English
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  • 45
    Publication Date: 2024-05-24
    Description: Numerous scientific reports have evidenced the transformation of the earth system due to human activities. These changes – captured under the term ‘Anthropocene’ – require a new perspective on global law and policy. The concept of ‘earth system law’ situates law in an earth system context and offers a new perspective to interrogate the role of law in governing planetary challenges such as climate change. The discourse on earth system law has not yet fully recognised courts as actors that could shape climate governance, while climate litigation discourse has insufficiently considered aspects of earth system law. We posit that courts play an increasingly influential climate governance role and that they need to be recognised as Anthropocene institutions within the earth system law paradigm. Drawing on a set of prominent climate cases, we discuss five inter-related domains that are relevant for earth system law and where the potential influence of courts can be discerned: establishing accountability, redefining power relations, remedying vulnerabilities and injustices, increasing the reach and impact of international climate law and applying climate science to adjudicate legal disputes. We suggest that their innovative work in these domains could provide a basis for positioning courts as planetary climate governance actors.
    Language: English
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  • 46
    Publication Date: 2024-05-24
    Description: Germany, the European Union member state with the largest fiscal space and its leading manufacturer of industrial goods, is pursuing an ambitious hydrogen strategy aiming at establishing itself as a major technology provider and importer of green hydrogen. The success of its hydrogen strategy represents not only a key element in realizing the European vision of climate neutrality but also a central driver of an emerging global hydrogen economy. This article provides a detailed review of German policy, highlighting its prominent international dimension and its implications for the development of a global renewable hydrogen economy. It provides an overview of the strategy's central goals and how these have evolved since the launch of the strategy in 2020. Next, it moves on to provide an overview of the strategy's main areas of intervention and highlights corresponding policy instruments. For this, we draw on a comprehensive assessment of hydrogen policy instruments, which have been systematically analyzed and coded. This was complemented by a detailed analysis of policy documents and information gathered in six interviews with government officials and staff of key implementing agencies. The article places particular emphasis on the strategy's international dimension. While less significant in financial terms than domestic hydrogen-related spending, it represents a defining feature of the German hydrogen strategy, setting it apart from strategies in other major economies. The article closes with a reflection on the key features of the strategy compared to other important countries, identifies gaps of the strategy and discusses important avenues for future research.
    Language: English
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  • 47
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    In:  Review of European, Comparative & International Environmental Law
    Publication Date: 2024-05-24
    Description: In two recent South African cases, Indigenous communities successfully challenged proposed fossil fuel exploration activities by the Shell petroleum company off South Africa's pristine West Coast. In contrast to earlier climate litigation cases in South Africa, the litigants relied specifically on their Indigenous rights and knowledge. In this case note, we highlight the ways in which the two courts engaged with the communities' cultural beliefs and practices as well as their knowledge related to sustainability and how this relates to protecting their livelihoods, cultural practices and identities that are threatened by the proposed activities. We highlight the important role played by Indigenous communities in the climate movement and argue that, in the future, Indigenous and related considerations could provide a strong basis for climate litigation in South Africa and potentially contribute to efforts to protect Indigenous communities against the activities of carbon majors.
    Language: English
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  • 48
    Publication Date: 2024-05-24
    Description: This article presents an enhanced emission module for the PALM model system, which collects discrete emission sources from different emission sectors and assigns them dynamically to the prognostic equations for specific pollutant species as volumetric source terms. Bidirectional lookup between each source location and cell index are maintained through using a hash key approach, while allowing all emission source modules to be conceived, developed and operated in a homogeneous and mutually independent manner. An additional generic emission mode has also been implemented to allow the use of external emission data in simulation runs. Results from benchmark runs indicate a high level of performance and scalability. Subsequently, a module for modelling parametrized emissions from domestic heating is implemented under this framework, using the approach of building energy usage and temperature deficit as a generalized form of heating degree days. An model run has been executed under idealized conditions by considering solely dispersion of PM10 from domestic heating sources. The results demonstrate a strong overall dependence on the strength and clustering of individual sources, diurnal variation in domestic heat usage, as well as the temperature deficit between the ambient and the user-defined target temperature. Vertical transport contributes additionally to a rapid attenuation of daytime PM10. Although urban topology plays a minor role on the pollutant concentrations at ground level, it has a relevant contribution to the vertical pollutant distribution.
    Language: English
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  • 49
    Publication Date: 2024-05-24
    Description: Key message: A decolonial approach is needed to fulfil IASC’s commitment to recognizing that Traditional Knowledge, Indigenous Knowledge and academic scientific knowledge are co-equal and complementary knowledge systems that all can and should inform its work (website ICARP IV, retrieved October 2023). This document summarizes key recommendations for actions regarding five themes: 1. Indigenous Peoples’ right to self-determination as a prerequisite for high-quality Arctic research 2. Ethics, methods and methodology as key for decolonial research 3. Indigenous-led research in design and practice 4. Indigenous Peoples’ co-equal participation in Arctic research funding structures and decision-making for securing decolonial Arctic research in practice 5. Funding for Co-Creative and Indigenous-Led Arctic Research
    Language: English
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  • 50
    Publication Date: 2024-05-24
    Type: Thesis , NonPeerReviewed
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  • 51
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    GEOMAR Helmholtz Centre for Ocean Research
    Publication Date: 2024-05-24
    Description: This julia package implements various tools for working with simple, non-marked, one dimensional point processes. In special it implements a bootstrap-based goodness-of-fit test for parametric models.
    Type: Software , NonPeerReviewed
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  • 52
    Publication Date: 2024-05-24
    Description: Europe’s recent summer droughts have had devastating ecological and economic consequences, but the severity and cause of these extremes remain unclear. Here we present 27,080 annually resolved and absolutely dated measurements of tree-ring stable carbon and oxygen (δ13C and δ18O) isotopes from 21 living and 126 relict oaks (Quercus spp.) used to reconstruct central European summer hydroclimate from 75 BCE to 2018 CE. We find that the combined inverse δ13C and δ18O values correlate with the June–August Palmer Drought Severity Index from 1901–2018 at 0.73 (P 〈 0.001). Pluvials around 200, 720 and 1100 CE, and droughts around 40, 590, 950 and 1510 CE and in the twenty-first century, are superimposed on a multi-millennial drying trend. Our reconstruction demonstrates that the sequence of recent European summer droughts since 2015 CE is unprecedented in the past 2,110 years. This hydroclimatic anomaly is probably caused by anthropogenic warming and associated changes in the position of the summer jet stream.
    Type: Article , PeerReviewed
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  • 53
    Publication Date: 2024-05-24
    Description: Observations of spatio-temporal variability of the deep ocean are rare and little is known about occurrence of deep ocean mesoscale dynamics. Here, we make use of 2.5 years of time series data from three distributed sensor arrays, which acquired high-resolution temperature, pressure and sound speed data of the bottom layer offshore northern Chile. Estimating salinity and density from the direct observations enable access to the full spectrum of hydrographic variability from a multi-hourly to annual time scale and with average inter-station distances of less than 1 km. Analyses revealed interannual warming over the continental slope of 0.002 °C yr−1–0.003 °C yr−1, and could trace periodic hydrographic anomalies, likely related to coastal-trapped waves, as far as to the lower continental slope. A concurrent change in the shape of the warm anomalies and the rate of deep-sea warming that occurs with the crossing of the deep-sea trench suggests that the abyssal part of the eastern boundary current system off Chile does not extend past the deep sea trench. Furthermore, the comparison of anomaly timing and shape in between stations implies southwards flow over the mid to lower continental slope, centred closer to the trench.
    Type: Article , PeerReviewed
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  • 54
    Publication Date: 2024-05-24
    Description: We evaluated how ranges of four endemic and non-endemic aquatic ostracode species changed in response to long-term (glacial–interglacial cycles) and abrupt climate fluctuations during the last 155 kyr in the northern Neotropical region. We employed two complementary approaches, fossil records and species distribution models (SDMs). Fossil assemblages were obtained from sediment cores PI-1, PI-2, PI-6 and Petén-Itzá 22-VIII-99 from the Petén Itzá Scientific Drilling Project, Lake Petén Itzá, Guatemala. To obtain a spatially resolved pattern of (past) species distribution, a downscaling cascade is employed. SDMs were reconstructed for the last interglacial (∼120 ka), the last glacial maximum (∼22 ka) and the middle Holocene (∼6 ka). During glacial and interglacial cycles and marine isotope stages (MISs), modelled paleo-distributions and paleo-records show the nearly continuous presence of endemic and non-endemic species in the region, suggesting negligible effects of long-term climate variations on aquatic niche stability. During periods of abrupt ecological disruption such as Heinrich Stadial 1 (HS1), endemic species were resilient, remaining within their current areas of distribution. Non-endemic species, however, proved to be more sensitive. Modelled paleo-distributions suggest that the geographic range of non-endemic species changed, moving southward into Central America. Due to the uncertainties involved in the downscaling from the global numerical to the highly resolved regional geospatial statistical modelling, results can be seen as a benchmark for future studies using similar approaches. Given relatively moderate temperature decreases in Lake Petén Itzá waters (∼5 ∘C) and the persistence of some aquatic ecosystems even during periods of severe drying in HS1, our data suggest (1) the existence of micro-refugia and/or (2) continuous interaction between central metapopulations and surrounding populations, enabling aquatic taxa to survive climate fluctuations in the northern Neotropical region.
    Type: Article , PeerReviewed
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  • 55
    Publication Date: 2024-05-24
    Description: Highlights • Investigation into the potential of Porites microatolls for SST reconstruction. • Comparison between recent and more conventional coral paleoclimatology methods. • Application of Srsingle bondU and Li/Mg paleothermometer. • Accuracy and reproducibility of Sr/Ca proved to be the most suitable proxy for SST reconstruction. Abstract Massive dome-shaped coral Porites are the predominant choice for paleoclimate studies due to their consistent and reliable growth. When growing close to sea level, they become limited in their vertical growth and form so-called ‘microatolls’. Microatolls have not yet been extensively explored for paleoclimate reconstruction. Here, we investigate how reliable modern Porites microatolls are against empirical sea-surface temperature using Sr/Ca, δ18O, Li/Mg and Srsingle bondU paleothermometry methods on samples from the Society Islands, French Polynesia. Our results show Sr/Ca ratios have the lowest Standard Error of the Inverse Prediction (SEIP) at 0.415 °C (N = 41) with a calibration of Sr/Ca (mmol mol−1) = −0.082 ± 0.006 SST (°C) + 11.256 ± 0.170 and with high reproducibility across multiple corals. The reproducibility of δ18O was less good, with SEIP increasing to 0.829 °C (N = 41). Considering methods directly from the literature, Li/Mg ratio empirically corrected for Sr/Ca had the best balance between bias and precision where no local calibration could be available. This study independently evaluates and confirms the suitability of Porites microatolls from well-flushed environments for paleoclimate studies. Fossil dome-shaped Porites grow anywhere between near-surface and roughly 20 m depths which inherently incorporates uncertainty into any sea surface temperature reconstruction. This uncertainty is significantly reduced for microatolls due to their well-constrained bathymetry. The study represents a fundamental step in paleoclimate research targeting consistently near the water-air interface bringing reliability and, especially when combined with their ability to reconstruct past sea-level changes, microatolls have the potential to be central for future paleoenvironmental studies.
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  • 56
    Publication Date: 2024-05-24
    Description: After a successful conquest of large parts of Syria in 1258 and 1259 CE, the Mongol army lost the battle of 'Ayn Jālūt against Mamluks on September 3, 1260 CE. Recognized as a turning point in world history, their sudden defeat triggered the reconfiguration of strategic alliances and geopolitical power not only in the Middle East, but also across much of Eurasia. Despite decades of research, scholars have not yet reached consensus over the causes of the Mongol reverse. Here, we revisit previous arguments in light of climate and environmental changes in the aftermath of one the largest volcanic forcings in the past 2500 years, the Samalas eruption ~1257 CE. Regional tree ring-based climate reconstructions and state-of-the-art Earth System Model simulations reveal cooler and wetter conditions from spring 1258 to autumn 1259 CE for the eastern Mediterranean/Arabian region. We therefore hypothesize that the post-Samalas climate anomaly and associated environmental variability affected an estimated 120,000 Mongol soldiers and up to half a million of their horses during the conquest. More specifically, we argue that colder and wetter climates in 1258 and 1259 CE, while complicating and slowing the campaign in certain areas, such as the mountainous regions in the Caucasus and Anatolia, also facilitated the assault on Syria between January and March 1260. A return to warmer and dryer conditions in the summer of 1260 CE, however, likely reduced the regional carrying capacity and may therefore have forced a mass withdrawal of the Mongols from the region that contributed to the Mamluks’ victory. In pointing to a distinct environmental dependency of the Mongols, we offer a new explanation of their defeat at 'Ayn Jālūt, which effectively halted the further expansion of the largest ever land-based empire.
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  • 57
    Publication Date: 2024-05-24
    Description: Global projections of macroeconomic climate-change damages typically consider impacts from average annual and national temperatures over long time horizons. Here we use recent empirical findings from more than 1,600 regions worldwide over the past 40 years to project sub-national damages from temperature and precipitation, including daily variability and extremes. Using an empirical approach that provides a robust lower bound on the persistence of impacts on economic growth, we find that the world economy is committed to an income reduction of 19% within the next 26 years independent of future emission choices (relative to a baseline without climate impacts, likely range of 11–29% accounting for physical climate and empirical uncertainty). These damages already outweigh the mitigation costs required to limit global warming to 2 °C by sixfold over this near-term time frame and thereafter diverge strongly dependent on emission choices. Committed damages arise predominantly through changes in average temperature, but accounting for further climatic components raises estimates by approximately 50% and leads to stronger regional heterogeneity. Committed losses are projected for all regions except those at very high latitudes, at which reductions in temperature variability bring benefits. The largest losses are committed at lower latitudes in regions with lower cumulative historical emissions and lower present-day income.
    Language: English
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  • 58
    Publication Date: 2024-05-24
    Description: Are there group decision methods which (i) give everyone, including minorities, an equal share of effective decision power even when voters act strategically, (ii) promote consensus and equality, rather than polarization and inequality, and (iii) do not favour the status quo or rely too much on chance? We describe two non-deterministic group decision methods that meet these criteria, one based on automatic bargaining over lotteries, the other on conditional commitments to approve compromise options. Using theoretical analysis, agent-based simulations and a behavioral experiment, we show that these methods prevent majorities from consistently suppressing minorities, which can happen in deterministic methods, and keeps proponents of the status quo from blocking decisions, as in other consensus-based approaches. Our simulations show that these methods achieve aggregate welfare comparable to common voting methods, while employing chance judiciously, and that the welfare costs of fairness and consensus are small compared to the inequality costs of majoritarianism. In an incentivized experiment with naive participants, we find that a sizable fraction of participants prefers to use a non-deterministic voting method over Plurality Voting to allocate monetary resources. However, this depends critically on their position within the group. Those in the majority show a strong preference for majoritarian voting methods.
    Language: English
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  • 59
    Publication Date: 2024-05-23
    Description: 〈title xmlns:mml="http://www.w3.org/1998/Math/MathML"〉Abstract〈/title〉〈p xmlns:mml="http://www.w3.org/1998/Math/MathML" xml:lang="en"〉NASA's Juno mission delivered gravity data of exceptional quality. They indicate that the zonal winds, which rule the dynamics of Jupiter's cloud deck, must slow down significantly beyond a depth of about 3,000 km. Since the underlying inversion is highly non‐unique additional constraints on the flow properties at depth are required. These could potentially be provided by the magnetic field and its Secular Variation (SV) over time. However, the role of these zonal winds in Jupiter's magnetic field dynamics is little understood. Here we use numerical simulations to explore the impact of the zonal winds on the dynamo field produced at depth. We find that the main effect is an attenuation of the non‐axisymmetric field, which can be quantified by a modified magnetic Reynolds number Rm that combines flow amplitude and electrical conductivity profile. Values below Rm = 3 are required to retain a pronounced non‐axisymmetric feature like the Great Blue Spot (GBS), which seems characteristic for Jupiter's magnetic field. This allows for winds reaching as deep as 3,400 km. A SV pattern similar to the observation can only be found in some of our models. Its amplitude reflects the degree of cancellation between advection and diffusion rather than the zonal wind velocity at any depth. It is therefore not straightforward to make inferences on the deep structure of cloud‐level winds based on Jupiter's SV.〈/p〉
    Description: Plain Language Summary: The dynamics in Jupiter's cloud layer is dominated by eastward and westward directed wind jets that circumvent the planet and reach velocities of up to 150 m per second. For the first time, NASA's Juno mission could measure the tiny gravity changes caused by these winds. The data show that the winds reach down to a depth of about 3,000 km, roughly 4% of Jupiter's radius. However, the interpretation is difficult and several alternative wind profiles have been suggested. In this paper we use numerical simulations to explore how these winds would affect Jupiter's magnetic field, which has also been measured with high precision by Juno. The field shows a strong inward‐directed local patch just south of the equator, called the GBS. The impact of the winds on the magnetic field rapidly increases with depth because of the increase in the electrical conductivity. Our simulations show that winds reaching deeper than about 3,400 km would practically wipe out the GBS. This confirms that they have to remain shallower. Juno also observed an east‐ward drift of the GBS. While some of our simulations also show an east‐ward drift it is typically much too slow.〈/p〉
    Description: Key Points: 〈list list-type="bullet"〉 〈list-item〉 〈p xml:lang="en"〉We study the magnetic field variations caused by Jupiter's deep‐reaching surface winds for various flow and electrical conductivity models〈/p〉〈/list-item〉 〈list-item〉 〈p xml:lang="en"〉Zonal winds reaching deeper than 3,400 km would yield a very axisymmetric surface field and are thus unrealistic〈/p〉〈/list-item〉 〈list-item〉 〈p xml:lang="en"〉It seems questionable that Jupiter's secular variation carries any useful information on the zonal winds〈/p〉〈/list-item〉 〈/list〉 〈/p〉
    Description: Engineering and Physical Sciences Research Council http://dx.doi.org/10.13039/501100000266
    Description: https://doi.org/10.17617/3.CNVRWD
    Keywords: ddc:523 ; Jupiter ; magnetic field ; atmospheric dynamics ; zonal winds
    Language: English
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  • 60
    Publication Date: 2024-05-23
    Description: 〈title xmlns:mml="http://www.w3.org/1998/Math/MathML"〉Abstract〈/title〉〈p xmlns:mml="http://www.w3.org/1998/Math/MathML" xml:lang="en"〉The microphysical structure of the lunar regolith provides information on the geologic history of the Moon. We used remote sensing measurements of thermal emission and a thermophysical model to determine the microphysical properties of the lunar regolith. We expand upon previous investigations by developing a microphysical thermal model, which more directly simulates regolith properties, such as grain size and volume filling factor. The modeled temperatures are matched with surface temperatures measured by the Diviner Lunar Radiometer Experiment on board the Lunar Reconnaissance Orbiter. The maria and highlands are investigated separately and characterized in the model by a difference in albedo and grain density. We find similar regolith temperatures for both terrains, which can be well described by similar volume filling factor profiles and mean grain sizes obtained from returned Apollo samples. We also investigate a significantly lower thermal conductivity for highlands, which formally also gives a very good solution, but in a parameter range that is well outside the Apollo data. We then study the latitudinal dependence of regolith properties up to ±80° latitude. When assuming constant regolith properties, we find that a variation of the solar incidence‐dependent albedo can reduce the initially observed latitudinal gradient between model and Diviner measurements significantly. A better match between measurements and model can be achieved by a variation in intrinsic regolith properties with a decrease in bulk density with increasing latitude. We find that a variation in grain size alone cannot explain the Diviner measurements at higher latitudes.〈/p〉
    Description: Plain Language Summary: The Moon is covered by a layer of fine grained material called regolith. To extract information about the regolith, such as grain size or stratification, we used data from the Diviner instrument on board the Lunar Reconnaissance Orbiter. Diviner measures the surface temperature of the regolith for each location on the Moon and all times during day and night. To derive regolith properties, we developed a model and varied its model parameters until the simulated surface temperatures matched the measured ones. We applied the model up to a latitude of 80° and find as the best solution a decrease in regolith packing density with increasing latitude. We also find that a variation of regolith grain size alone cannot explain the measurements. These predictions are valuable for planning future missions targeting higher latitudes and can be compared with future in situ measurements and returned samples. However, the fraction of sunlight that actually heats the regolith is quite unknown, especially at high latitudes. A variation of this fraction can explain the measured surface temperatures reasonably well even without a variation of the regolith properties with latitude.〈/p〉
    Description: Key Points: 〈list list-type="bullet"〉 〈list-item〉 〈p xml:lang="en"〉We developed a microphysical thermal model accounting for regolith grain size and volume filling factor〈/p〉〈/list-item〉 〈list-item〉 〈p xml:lang="en"〉The best match between model and Lunar Reconnaissance Orbiter/Diviner data was achieved with a decrease in bulk density between 30° and 80° latitude〈/p〉〈/list-item〉 〈list-item〉 〈p xml:lang="en"〉We also found a reasonable agreement between observed and modeled surface temperatures when varying the solar incidence dependent albedo〈/p〉〈/list-item〉 〈/list〉 〈/p〉
    Description: LRO project
    Description: https://doi.org/10.17189/WJ0S-W188
    Description: https://doi.org/10.5281/zenodo.8433837
    Description: https://doi.org/10.5281/zenodo.10781188
    Keywords: ddc:523 ; Moon ; regolith ; Diviner ; thermal modeling ; lunar
    Language: English
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  • 61
    Publication Date: 2024-05-23
    Description: 〈title xmlns:mml="http://www.w3.org/1998/Math/MathML"〉Abstract〈/title〉〈p xmlns:mml="http://www.w3.org/1998/Math/MathML" xml:lang="en"〉The Ries impact structure (Germany) contains well‐preserved ejecta deposits consisting of melt‐free lithic breccia (Bunte Breccia) overlain by suevite. To test their emplacement conditions, we investigated the magnetic properties and microstructures of 26 polymict breccia clasts and a stratigraphic profile from the clasts into the suevite at the Aumühle quarry. Remanent magnetization directions of the Bunte Breccia clasts fall into two groups: those whose directions mostly lie parallel to the reversed field during impact carried mostly by magnetite, and those whose directions vary widely among each clast carried by titanohematite. Basement clasts containing titanohematite acquired a chemical remanent magnetization (CRM) during the ejection process and then rotated during turbulent deposition. Clasts of sedimentary rocks grew magnetite after turbulent deposition, with CRM directions lying parallel to the paleofield. Suevite holds a thermal remanent magnetization carried by magnetite, except for ∼12 cm from the contact with the Bunte Breccia, where hematite concentrations increase due to hydrothermal alteration. These observations lead us to propose a three‐stage model of (a) turbulent deposition of the melt‐free breccia with clast rotation 〈580°C, (b) deposition of the overlying suevite, which acted as a semi‐permeable barrier that confined hot (〈300°C) oxidizing fluids to the permeable breccia zone, and (c) prolonged hydrothermal activity producing further alteration which ended before the next geomagnetic reversal. Basement outcrops have significantly different magnetic properties than the Bunte Breccia basement clasts with similar lithology. Two basement blocks situated near the inner ring may have been thermally overprinted up to 550°C.〈/p〉
    Description: Plain Language Summary: The 26‐km‐diameter, ∼15‐million‐year‐old Ries meteorite impact structure in southern Germany is characterized by well‐preserved ejecta deposits expelled from the crater within seconds after the impact. These deposits consist of two main layers: melt‐free, lithic breccia (Bunte Breccia), overlain by melt‐bearing breccia (suevite). To understand the formation conditions of the ejecta deposits, we performed paleomagnetic and rock magnetic measurements and microstructural experiments on clasts within Bunte Breccia and on the overlying suevite at the Aumühle quarry. We found that clasts derived from crystalline basement materials experienced high pressures during the impact. These clasts had randomly oriented magnetization directions carried by titanohematite. In contrast, clasts derived from sedimentary rocks experienced only low pressures and had coherent magnetization directions oriented parallel to the reversed field during the impact that are carried by magnetite. Our findings can be interpreted by a three‐stage model that explains the thermal and structural formation of impact ejecta at the Ries impact structure.〈/p〉
    Description: Key Points: 〈list list-type="bullet"〉 〈list-item〉 〈p xml:lang="en"〉Randomly oriented paleomagnetic directions in basement clasts in ejecta deposits suggest turbulent emplacement〈/p〉〈/list-item〉 〈list-item〉 〈p xml:lang="en"〉Bunte Breccia was chemically altered and locally heated by the overlying suevite, resulting in hydrothermal activity up to 300°C〈/p〉〈/list-item〉 〈list-item〉 〈p xml:lang="en"〉Basement rocks near the inner ring may have experienced temperatures up to 550°C from cratering〈/p〉〈/list-item〉 〈/list〉 〈/p〉
    Description: Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659
    Description: https://earthref.org/MagIC/19984
    Keywords: ddc:622.153 ; Paleomagnetism ; remanent magnetization ; chemical remanence ; impact crater ; impact ejecta ; hydrothermal activity
    Language: English
    Type: doc-type:article
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  • 62
    Publication Date: 2024-05-23
    Description: 〈title xmlns:mml="http://www.w3.org/1998/Math/MathML"〉Abstract〈/title〉〈p xmlns:mml="http://www.w3.org/1998/Math/MathML" xml:lang="en"〉Hydrochemical data of karst springs provide valuable insights into the internal hydrodynamical functioning of karst systems and support model structure identification. However, the collection of high‐frequency time series of major solute species is limited by analysis costs. In this study, we develop a method to retrieve the individual solute concentration time series and their uncertainty at high temporal resolution for karst springs by using continuous observations of electrical conductivity (EC) and low‐frequency ionic measurements. Due to the large ion content and non‐negligible concentrations of aqueous complexes in karst systems, the concentration of each solute species occurring as free ion and as part of aqueous complexes are computed separately. The concentration of species occurring as free ions are computed considering their contributions to the total EC, whereas the concentration of the species as part of complexes are obtained from speciation calculations. The pivotal role of the complexation processes for the reconstruction of solute concentration time series starting from the EC signal is investigated in two karstic catchments with different geologies and temporal resolution of the available hydrochemical datasets, that is the Kerschbaum dolostone system in Austria and the Baget limestone system in France. The results show that complexation processes are significant and should be considered for the estimation of the total solute concentration in case of SO〈sub〉4〈/sub〉, Ca, Mg and HCO〈sub〉3〈/sub〉. The EC signal of a karst spring can be used to interpolate and quantify the dynamics of those solutes characterized by large contribution (approximately >6%) to the total EC and low relative variability, that is HCO〈sub〉3〈/sub〉, Ca and Mg. Moreover, the presented method can be used to estimate concentrations of solutes when applied to karst systems with stationary and hydrogeochemical homogeneous contributing area. On the contrary, the method is affected by large uncertainty in case of dynamic systems characterized by varying contributions of water from different geological areas. This study aims to contribute to the problem of hydrogeochemical data availability and to support future works on karst systems conceptualization.〈/p〉
    Description: Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659
    Description: École Polytechnique Fédérale de Lausanne http://dx.doi.org/10.13039/501100001703
    Description: European Regional Development Fund http://dx.doi.org/10.13039/501100008530
    Description: http://www.hydroshare.org/resource/fb92daaffced415fb7a991747e73adfa
    Keywords: ddc:551.9 ; electrical conductivity decomposition ; high‐resolution hydrochemical data ; hydrochemical modelling ; karst
    Language: English
    Type: doc-type:article
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  • 63
    Publication Date: 2024-05-23
    Description: 〈title xmlns:mml="http://www.w3.org/1998/Math/MathML"〉Abstract〈/title〉〈p xmlns:mml="http://www.w3.org/1998/Math/MathML" xml:lang="en"〉The Bakreswar geothermal province represents a medium enthalpy geothermal system with its Bakreswar and Tantloie hot springs. It lies within the Chotanagpur Granite Gneissic Complex in the eastern part of the Indian Peninsula. The province has a high heat flow and a high geothermal gradient of 90°C/km. Magnetotelluric data from 95 sites in a frequency range of 10 kHz–10 Hz were acquired over the Bakreswar geothermal province to obtain an electrical conductivity model and map the geothermal reservoir with its fluid pathways and related geological structures. Subsurface conductivity models obtained from three‐dimensional inversions of the Magnetotelluric data exhibit several prominent anomalies, which are supplemented by gravity results. The conductivity model maps three features which act as a conduit (a) a northwest–southeast trending feature, (b) an east–west trending feature to the south of the northwest–southeast trending feature (which lies 1 km north of the Oil and Natural Gas Corporation fault marked by previous studies) and (c) shallow conducting features close to Bakreswar hot spring. The northwest–southeast trending feature coincides with the boundary of the high‐density intrusive block. This northwest–southeast trending feature provides the pathway for the meteoric water to reach a maximum depth of 2.7 km, where it gets heated by interacting with deep‐seated structures and then it rises towards the surface. The radiogenic process occurring within the granites of Chotanagpur Granite Gneissic Complex provides the heat responsible for heating the meteoric water. The northwest–southeast and east–west trending features are responsible for the transport of meteoric water to deeper depths and then towards the shallow regions of the Earth. The near surface features close to the Bakreswar hot spring are responsible for carrying the water further towards the hot spring. The resistivity of these structures plotted as a function of salinity and temperatures for saline crustal fluids suggests the involvement of meteoric water. Further, applying Archie's law to this resistivity suggests that the conduit path has a porosity greater than 10%. This study successfully maps the anomalous structures which might foster the migration of geothermal fluid in Bakreswar geothermal province.〈/p〉
    Description: Deutscher Akademischer Austauschdienst (DAAD)
    Keywords: ddc:622.15 ; electromagnetics ; geothermal ; gravity ; inversion ; magnetotellurics ; modelling
    Language: English
    Type: doc-type:article
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  • 64
    Publication Date: 2024-05-23
    Description: 〈title xmlns:mml="http://www.w3.org/1998/Math/MathML"〉Abstract〈/title〉〈p xmlns:mml="http://www.w3.org/1998/Math/MathML" xml:lang="en"〉Despite extensive investigation, the tectono‐thermal evolution of the Archean crust in the Lewisian Gneiss Complex in NW Scotland (LGC) is debated. Most U–Pb zircon geochronological and metamorphic studies have focused on rocks from the central region of the mainland LGC, where granulite facies assemblages associated with the oldest (Badcallian) tectono‐metamorphic event at c. 2.75 Ga are overprinted by younger amphibolite facies assemblages related to the Inverian (c. 2.5 Ga) and subsequent Laxfordian (c. 1.9–1.65 Ga) tectono‐thermal events. In the southern and northern regions of the mainland LGC, deformation and metamorphism associated with the Laxfordian event are pervasive, although the timing and conditions are poorly constrained. Here, we present new field, petrographic and structural data, U–Pb zircon and titanite geochronology and phase equilibrium modelling of amphibolite samples from the northern and southern regions. Our field observations show that in both regions, pre‐Laxfordian structures are significantly reworked by steep NW‐striking fabrics that are themselves pervasively overprinted by co‐axial deformation and amphibolite facies metamorphism related to the Laxfordian event. In situ U–Pb titanite geochronology yields Laxfordian ages of 1853 ± 20 Ma in the southern region (P = 6–8 kbar and T = 640–690°C) and 1750 ± 20 Ma and 1776 ± 10 Ma in the northern region (P = 6–7.5 kbar and T = 740–760°C). While U–Pb dating of zircon rims from felsic gneisses in the central region shows a dominant Inverian metamorphic overprint at c. 2500 Ma, zircon rims in felsic gneisses from the northern and southern regions commonly yield Laxfordian dates as young as c. 1800 Ma. Combined, the results support the idea that, during the Palaeoproterozoic, the central region of the LGC acted as low‐strain domain, in which intense deformation and metamorphism were restricted to crustal‐scale shear zones. By contrast, in the southern and northern regions, early (c. 1.85 Ga) and late (c. 1.75 Ga) Laxfordian deformation and fluid‐mediated metamorphism were much more pervasive and at higher P–T conditions than previously proposed. The diachronous Laxfordian evolution of the southern and northern regions indicate that they reflect early and late snapshots of collisional to transpressional tectonics in the mainland LGC. The long‐lasting Laxfordian evolution documents the collision of the Rae and North Atlantic cratons during the Palaeoproterozoic amalgamation of the supercontinent Nuna, with implications for the palaeogeographic configuration of NW Scotland during Palaeoproterozoic Nuna.〈/p〉
    Description: Australian Research Council http://dx.doi.org/10.13039/501100000923
    Description: Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659
    Keywords: ddc:552.4 ; in situ titanite petrochronology ; Laxfordian metamorphism ; North Atlantic Craton ; strain partitioning ; supercontinent assembly
    Language: English
    Type: doc-type:article
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  • 65
    Publication Date: 2024-05-23
    Description: 〈title xmlns:mml="http://www.w3.org/1998/Math/MathML"〉Abstract〈/title〉〈p xmlns:mml="http://www.w3.org/1998/Math/MathML" xml:lang="en"〉The 6 February 2023, 〈italic〉M〈/italic〉〈sub〉〈italic〉w〈/italic〉〈/sub〉 7.8 Pazarcık earthquake in the Turkey‐Syria border region raises the question of whether such a large earthquake could have been foreseen, as well as what is the maximum possible magnitude (〈italic〉M〈/italic〉〈sub〉max〈/sub〉) of earthquakes on the East Anatolian Fault (EAF) system and on continental transform faults in general. To answer such questions, knowledge of past earthquakes and of their causative faults is necessary. Here, we integrate data from historical seismology, paleoseismology, archeoseismology, and remote sensing to identify the likely source faults of fourteen 〈italic〉M〈/italic〉〈sub〉〈italic〉w〈/italic〉〈/sub〉 ≥ 7 earthquakes between 1000 CE and the present in the region. We find that the 2023 Pazarcık earthquake could have been foreseen in terms of location (the EAF) and timing (an earthquake along this fault was if anything overdue), but not magnitude. We hypothesize that the maximum earthquake magnitude for the EAF is in fact 8.2, that is, a single end‐to‐end rupture of the entire fault, and that the 2023 Pazarcık earthquake did not reach 〈italic〉M〈/italic〉〈sub〉max〈/sub〉 by a fortuitous combination of circumstances. We conclude that such unusually large events are hard to model in terms of recurrence intervals, and that seismic hazard assessment along continental transforms cannot be done on individual fault systems but must include neighboring systems as well, because they are not kinematically independent at any time scale.〈/p〉
    Description: Plain Language Summary: On 6 February 2023, there was a magnitude 7.8 earthquake in the Turkey‐Syria border region. It surprised many people, including many Earth scientists, because of where it happened (on the East Anatolian fault [EAF]) and because of how large it was. People wondered whether it could have been foreseen, and how large an earthquake on this fault can really be. To figure this out, we looked at the history of earthquakes in the region in the last 1,000 years. We used information from historical seismology, paleoseismology, archeoseismology, and remote sensing to identify the faults that caused 14 earthquakes with magnitude 7 or greater in this region. We found that the location (EAF) and timing (it was due any time) of the 2023 earthquake were foreseeable, but not the magnitude. In fact, we believe that the maximum magnitude for the EAF is 8.2, and that the 2023 earthquake was below this maximum just by accident. It is hard to say how often such large events can happen, because many different things need to align. We also believe that it is necessary to look at neighboring fault systems when estimating seismic hazards, because they interact.〈/p〉
    Description: Key Points: 〈list list-type="bullet"〉 〈list-item〉 〈p xml:lang="en"〉We identified the source faults of 14 large earthquakes along the East Anatolian and northern Dead Sea fault systems〈/p〉〈/list-item〉 〈list-item〉 〈p xml:lang="en"〉Maximum magnitude for the East Anatolian Fault (EAF) zone is approximately 8.2〈/p〉〈/list-item〉 〈list-item〉 〈p xml:lang="en"〉Continental transforms may be described as having a collective memory〈/p〉〈/list-item〉 〈/list〉 〈/p〉
    Description: https://doi.org/10.5270/ESA-c5d3d65
    Description: https://doi.org/10.1029/2019EA000658
    Description: https://doi.org/10.5194/essd-14-4489-2022
    Description: https://doi.org/10.25577/EWT8-KY06
    Description: https://dx.doi.org/10.5285/df93e92a3adc46b9a5c4bd3a547cd242
    Description: https://doi.org/10.5066/P985I7U2
    Description: https://app.box.com/v/textureshading
    Keywords: ddc:551.22 ; East Anatolian fault ; Dead Sea fault ; seismic gap ; seismic hazards ; source fault ; maximum earthquake magnitude
    Language: English
    Type: doc-type:article
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  • 66
    Publication Date: 2024-05-23
    Description: 〈title xmlns:mml="http://www.w3.org/1998/Math/MathML"〉Abstract〈/title〉〈p xmlns:mml="http://www.w3.org/1998/Math/MathML" xml:lang="en"〉Teleseismic back‐projection imaging has emerged as a powerful tool for understanding the rupture propagation of large earthquakes. However, its application often suffers from artifacts related to the receiver array geometry. We developed a teleseismic back‐projection technique that can accommodate data from multiple arrays. Combined processing of P and pP waveforms may further improve the resolution. The method is suitable for defining arrays ad‐hoc to achieve a good azimuthal distribution for most earthquakes. We present a catalog of short‐period rupture histories (0.5–2.0 Hz) for all earthquakes from 2010 to 2022 with 〈italic〉M〈/italic〉〈sub〉〈italic〉W〈/italic〉〈/sub〉 ≥ 7.5 and depth less than 200 km (56 events). The method provides automatic estimates of rupture length, directivity, speed, and aspect ratio, a proxy for rupture complexity. We obtained short‐period rupture length scaling relations that are in good agreement with previously published relations based on estimates of total slip. Rupture speeds were consistently in the sub‐Rayleigh regime for thrust and normal earthquakes, whereas a tenth of strike‐slip events propagated at supershear speeds. Many rupture histories exhibited complex behaviors, for example, rupture on conjugate faults, bilateral propagation, and dynamic triggering by a P wave. For megathrust earthquakes, ruptures encircling asperities were frequently observed, with downdip, updip, and balanced patterns. Although there is a preference for short‐period emissions to emanate from central and downdip parts of the megathrust, emissions updip of the main asperity are more frequent than suggested by earlier results.〈/p〉
    Description: Plain Language Summary: Back‐projection is an earthquake imaging method based on seismic waveforms recorded remotely at a group of seismometers (seismic array). Here, we develop a new approach to combine backprojections from multiple arrays and seismic waveforms and use it to derive a catalog of large earthquake rupture histories from 2010 to 2022, providing a map view of the high‐frequency radiation emitted along the fault. The method automatically estimates the earthquake rupture length, speed, directivity, and aspect ratio. Based on these estimates, we obtained scaling relations between the earthquake magnitude and rupture length that agree with classical relationships. We identified strike‐slip earthquakes propagating at supershear, that is, faster than the shear wave speed, the usual limit for self‐sustaining rupture propagation. We observed complex rupture behaviors, for example, multiple faults activated, bilateral ruptures, and triggering of the main phase of a rupture by a primary (P) wave from the earliest part of the rupture. For subduction earthquakes, high‐frequency emissions were often observed, forming a ring around the fault interface patches (asperities) where the main slip occurs. There was a preference for high‐frequency radiation to emanate from central and deeper parts of the subducting plate interface, but shallower emissions were more frequent than expected from previous literature.〈/p〉
    Description: Key Points: 〈list list-type="bullet"〉 〈list-item〉 〈p xml:lang="en"〉We provide a complete catalog of high‐frequency rupture histories for 〈italic〉M〈/italic〉 ≥ 7.5 events 2010–2022〈/p〉〈/list-item〉 〈list-item〉 〈p xml:lang="en"〉We develop a semi‐automatic method for estimating rupture length, speed, directivity, and aspect ratio〈/p〉〈/list-item〉 〈list-item〉 〈p xml:lang="en"〉Both encircling ruptures and emissions updip of slip asperities common in megathrust earthquakes〈/p〉〈/list-item〉 〈/list〉 〈/p〉
    Description: National Agency for Research and Development (ANID)
    Description: https://doi.org/10.5880/GFZ.2.4.2024.001
    Keywords: ddc:551.22 ; back‐projection ; megathrust earthquakes ; complex ruptures ; supershear ruptures ; scaling relations ; earthquake rupture catalog
    Language: English
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  • 67
    Publication Date: 2024-05-23
    Description: 〈title xmlns:mml="http://www.w3.org/1998/Math/MathML"〉Abstract〈/title〉〈p xmlns:mml="http://www.w3.org/1998/Math/MathML" xml:lang="en"〉Craters on the lunar surface can provide valuable information about the timing and sequence of surface‐forming processes on the Moon. A commonly used method for age determination is the analysis of the crater size‐frequency distribution (CSFD) to which a production function (PF) is fitted that represents the size‐frequency distribution of the impactors. However, the commonly used PF of Neukum (1983) is valid for crater diameters between 10 m and 300 km. Neukum et al. (2001, 〈ext-link ext-link-type="uri" xlink:href="https://doi.org/10.1007/978-94-017-1035-0_3"〉https://doi.org/10.1007/978-94-017-1035-0_3〈/ext-link〉) revised the PF for crater diameters of 100 m–200 km. However, it is suggested to also be valid for the diameter range of 10 m–300 km as well. To assess whether we can extend a PF to craters ≤10 m in diameter, we investigated the slopes of the CSFDs of small craters formed on ejecta of young Copernican‐aged craters Giordano Bruno, Moore F, North Ray, and South Ray. A PF for smaller diameters would allow dating of young geological units, which are typically small, and would reduce the statistical error in age determinations, since smaller craters are more abundant. However, small craters are strongly influenced by geological factors, such as target properties, crater degradation, and secondary craters. For craters between 10 and 20 m we obtain a steeper CSFD slope than Neukum's proposed −3 slope (cumulative), whereas for craters ≤10 m the slope is about −3. We conclude that the PF of Neukum (1983) provides a reasonable CSFD slope for smaller craters, although it was not developed for this crater diameter range.〈/p〉
    Description: Plain Language Summary: Since the formation of the Moon, impactors have randomly hit the lunar surface. Older areas have larger and more abundant craters compared to younger areas. This relationship allows the determination of relative ages for different surfaces. A mathematical function can be fitted to the number and size of craters. This function has a specific shape and can be used to date a surface. Frequently used functions are valid between crater diameters of 10 m and 300 km. Dating young geological units is only possible if the observed craters are 〈bold〉≥〈/bold〉10 m in diameter. Therefore, an extension of these functions to crater diameters ≤10 m would be beneficial. However, small craters are strongly influenced by geological factors, such as target properties, crater degradation, and secondary craters. We consider these influences in our investigation. To compare our results with previous findings, we look more closely at the slope of the function that results from the number and size of the craters. Generally, we find that one function fits well for craters ≤10 m, even though it was not designed for this diameter range. This allows a more robust age determination because small craters are more abundant, reducing the statistical error.〈/p〉
    Description: Key Points: 〈list list-type="bullet"〉 〈list-item〉 〈p xml:lang="en"〉We studied small craters on young ejecta blankets to evaluate if the lunar production function (PF) is viable for craters ≤10 m〈/p〉〈/list-item〉 〈list-item〉 〈p xml:lang="en"〉The crater size‐frequency distributions (CSFDs) indicate that the PF can indeed be extended to crater diameters ≤10 m〈/p〉〈/list-item〉 〈list-item〉 〈p xml:lang="en"〉Our observed slopes of CSFDs at the studied Copernican‐aged craters are consistent with previous findings〈/p〉〈/list-item〉 〈/list〉 〈/p〉
    Description: Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659
    Description: Deutsches Zentrum für Luft‐ und Raumfahrt http://dx.doi.org/10.13039/501100002946
    Description: https://doi.org/10.35003/V9AFAZ
    Description: https://doi.org/10.17189/1520341
    Description: https://ode.rsl.wustl.edu/moon/
    Description: https://wms.lroc.asu.edu/lroc/rdr_product_select
    Description: https://astrogeology.usgs.gov/search/map/Moon/Clementine/UVVIS/Lunar_Clementine_UVVIS_Warp_ClrRatio_Global_200m
    Description: https://aaronclauset.github.io/powerlaws/
    Keywords: ddc:523 ; crater size‐frequency distribution ; production function ; slope ; small craters ; Moon
    Language: English
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  • 68
    facet.materialart.
    Unknown
    Kraatz, Berlin
    In:  SUB Göttingen | KART B 140:1289 | KART H 140:Königsberg-Ost
    Publication Date: 2024-05-23
    Description: Geologische Karte 1: 25 000 mit Erläuterungen. Digitalisat des FID GEO (Fachinformationsdienst Geowissenschaften), erstellt durch das GDZ (Göttinger Digitalisierungszentrum), Karte aus dem Bestand der SUB Göttingen. Koordinaten Vorlage: Nullmeridian Ferro E 038 10 – 038 20 / N 054 42 - 054 48.
    Description: map
    Description: DFG, SUB Göttingen
    Keywords: ddc:912 ; ddc:554.3 ; Geologische Karte
    Language: German
    Type: doc-type:carthographicMaterial
    Format: 78
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  • 69
    Publication Date: 2024-05-23
    Description: 〈title xmlns:mml="http://www.w3.org/1998/Math/MathML"〉Abstract〈/title〉〈p xmlns:mml="http://www.w3.org/1998/Math/MathML" xml:lang="en"〉To understand the global response of thermospheric‐ionospheric (TI) parameters to variations in solar irradiance measurements from the Global‐Scale Observations of the Limb and Disk (GOLD) ultraviolet imaging spectrograph, solar radio flux F10.7, predictions from the Coupled Thermosphere Ionosphere Plasmasphere electrodynamics (CTIPe) model, and International Global Navigation Satellite System Service total electron content maps (TEC) have been used. Various parameters such as GOLD 〈italic〉O〈/italic〉/〈italic〉N〈/italic〉〈sub〉2〈/sub〉, 〈italic〉O〈/italic〉〈sub〉2〈/sub〉, and the nighttime peak electron density (Nmax) have been compared with the CTIPe model simulations. The GOLD observed Nmax shows a number of significant features including a winter anomaly and an equatorial ionization anomaly. The comparison with solar proxies showed that the GOLD 〈italic〉Q〈/italic〉〈sub〉〈italic〉EUV〈/italic〉〈/sub〉 correlates very well with the EUV observations compared to the F10.7 index. The study also examined the relationship between the solar proxies and Nmax on different time scales and found that Nmax responded significantly to 〈italic〉Q〈/italic〉〈sub〉〈italic〉EUV〈/italic〉〈/sub〉 at both medium‐ and long‐term timescales. Furthermore, a low correlation between Nmax in the equatorial region and solar proxies was found. A delayed ionospheric TEC response against solar flux variations within the 27‐day solar rotation was investigated. This ionospheric delay of TEC with respect to solar flux was observed to be less than 1 day, which was reproduced in model simulations. The current study has shown that the GOLD observations can be used to investigate the delayed ionospheric response and to gain a better understanding of the influence of solar activity on the TI system.〈/p〉
    Description: Key Points: 〈list list-type="bullet"〉 〈list-item〉 〈p xml:lang="en"〉Ionospheric‐thermospheric parameters observed by Global‐Scale Observations of the Limb and Disk (GOLD) ultraviolet imaging spectrograph are compared with Coupled Thermosphere Ionosphere Plasmasphere electrodynamics model simulations〈/p〉〈/list-item〉 〈list-item〉 〈p xml:lang="en"〉The delayed ionospheric response against the solar flux is less than 1 day at the time scale of the 27 days solar rotation period〈/p〉〈/list-item〉 〈list-item〉 〈p xml:lang="en"〉The integrated 1–45 nm solar energy flux values observed by GOLD correlate well with the F10.7 and EUV〈/p〉〈/list-item〉 〈/list〉 〈/p〉
    Description: Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659
    Description: http://cddis.nasa.gov/Data_and_Derived_Products/GNSS/atmospheric_products.html
    Description: http://gold.cs.ucf.edu/search/
    Description: https://omniweb.gsfc.nasa.gov/form/dx1.html
    Description: https://lasp.colorado.edu/lisird/
    Description: http://guvitimed.jhuapl.edu/data/products
    Description: https://doi.org/10.5281/zenodo.8145356
    Keywords: ddc:538.7 ; CTIPe model ; O/N2 ratio ; ionospheric delay ; solar activity ; thermosphere‐ionosphere ; GOLD
    Language: English
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  • 70
    Publication Date: 2024-05-23
    Description: Eine erste taxonomische Übersicht der bisher unbeschriebenen Taphoflora aus dem Unterrotliegend (Oberkarbon – Unterperm) von Niedermoschel bei Alsenz (Saar-Becken-Becken, SW-Deutschland) wird vorgestellt. Die Flora umfasst nach aktuellem Kenntnisstand folgende Taxa: Lepidostrobophyllum sp., Sphenophyllum thoniiMAHR, Sphenophyllum cf. oblongifolium (GERMAR & KAULFUSS) UNGER, Sphenophyllum spp. (unbest. Achsen), Annularia spinulosa STERNBERG, Annularia spicata (GUTBIER) SCHIMPER, Asterophyllites equisetiformis (SCHLOTHEIM ex STERNBERG) BRONGNIART, Asterophyllites longifolius (STERNBERG) BRONGNIART, cf. Palaeostachya sp., Calamites spp., Scolecopteris cf. arborescens (SCHLOTHEIM ex BRONGNIART) STUR, Pecopteris (Scolecopteris) cf. oreopteridia (SCHLOTHEIM) BRONGNIART, Pecopteris (Scolecopteris) candolleana BRONGNIART, Pecopteris (Scolecopteris) cf. densifolia GÖPPERT, Pecopteris monyi ZEILLER, Pecopteris spp. indet, Remia pinnatifida (GUTBIER) KNIGHT, Asterotheca sternbergii (GÖPPERT) STUR, Crossotheca sp., Autunia conferta (STERNBERG) KERP, Rhachiphyllum schenkii (HEYER) KERP, Dicksonites pluckenetii (SCHLOTHEIM ex STERNBERG) STERZEL, cf. Neurodontopteris auriculata (BRONGNIART) POTONIÉ, Cordaites sp., Coniferae indet., Gomphostrobus bifidus (GEINITZ) POTONIÉ, cf. Dicranophyllum gallicum GRAND´EURY sowie verschiedene, nicht näher bestimmbare karpologische Reste, Wurzeln und Problematika. Die Flora repräsentiert damit eine der diversesten, bisher bekannt gewordenen Floren aus dem Unteren Rotliegend des Saar-Nahe-Beckens. Basierend auf der taxonomischen Zusammensetzung und der autökologischen Interpretation der nachgewiesenen Taxa wird die Taphoflora als eine allochthone Vermischung mindestens zweier Vegetationseinheiten gedeutet: der ufernahen, feuchtigkeitsliebenden Vegetation (deren Reste die Taphoflora dominieren) und der Vegetation des eher trockeneren Hinterlandes.
    Description: Abstract: A first taxonomic survey of the so far undescribed taphoflora from the Lower Rotliegend (Upper Carboniferous – Lower Permian) of Niedermoschel near Alsenz (Saar-Nahe basin, Southwest Germany) is presented. The following taxa have been identified so far: Lepidostrobophyllum sp., Sphenophyllum thoniiMAHR, Sphenophyllum cf. oblongifolium (GERMAR & KAULFUSS) UNGER, Sphenophyllum spp., Annularia spinulosa STERNBERG, Annularia spicata (GUTBIER) SCHIMPER, Asterophyllites equisetiformis (SCHLOTHEIM ex STERNBERG) BRONGNIART, Asterophyllites longifolius (STERNBERG) BRONGNIART , cf. Palaeostachya sp., Calamites spp., Scolecopteris cf. arborescens (SCHLOTHEIM ex BRONGNIART) STUR, Pecopteris (Scolecopteris) cf. oreopteridia (SCHLOTHEIM) BRONGNIART, Pecopteris (Scolecopteris) candolleana BRONGNIART, Pecopteris (Scolecopteris) cf. densifolia GÖPPERT, Pecopteris monyi ZEILLER, Pecopteris spp. indet, Remia pinnatifida (GUTBIER) KNIGHT, Asterotheca sternbergii (GÖPPERT) STUR, Crossotheca sp., Autunia conferta (STERNBERG) KERP, Rhachiphyllum schenkii (HEYER) KERP, Dicksonites pluckenetii (SCHLOTHEIM ex STERNBERG) STERZEL, cf. Neurodontopteris auriculata (BRONGNIART) POTONIÉ, Cordaites sp., Coniferae indet., Gomphostrobus bifidus (GEINITZ) POTONIÉ, cf. Dicranophyllum gallicum GRAND´EURY, as well as several unidentified carpological remains, roots and problematics. Thus this flora represents one of the most diverse (in terms of species richness) floras from the Lower Rotliegend of the Saar-Nahe basin. Based on the taxonomic composition and autecological interpretations of the taxa this flora is interpretated to represent an allochthonous mix of at least two different source vegetation types: i.e. from the vegetation of wet environments (dominating the assemblage) and the vegetation of the more dry Hinterland.
    Description: 1. Einleitung 2. Geologie und Material 3. Die Flora 3.1. Lycopsiden 3.2. Sphenopsiden 3.2.1. Calamiten 3.2.2. Sphenophyllen 3.3. Farne 3.4. Pteridospermen 3.4.1. Peltaspermaceen 3.4.2. Callistophytaceen 3.4.3. Medullosaceen 3.5. Cordaiten 3.6. Koniferen 3.7. „Koniferophyten“ 3.8. Incertae sedis und Problematika 4. Taphonomie und Ökologie Schriften
    Description: research
    Keywords: ddc:561 ; Saar-Nahe-Becken ; Rotliegend ; Paläobotanik
    Language: German
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  • 71
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    Taylor & Francis
    Publication Date: 2024-05-23
    Description: The extent of our duties to mitigate climate change is commonly conceptualized in terms of temperature goals like the 1.5°C and the 2°C target and corresponding emissions budgets. While I do acknowledge the political advantages of any framework that is relatively easy to understand, I argue that this particular framework does not capture the true extent of our mitigation duties. Instead I argue for a more differentiated approach that is based on the well-known distinction between subsistence and luxury emissions. At the heart of this approach lies the argument that we have no budget of substantial, net-positive luxury emissions left. In a world in which dangerous climate change has begun, we must expect all further substantial, net-positive luxury emissions to cause harm. Since they lack the kind of justification needed for them to be nevertheless permissible, I conclude that we must stop emitting them with immediate effect. I also briefly discuss the difficult case of subsistence emissions and offer some first thoughts on the morality of a third category of emissions, what I call ‘transition emissions’.
    Type: Article , PeerReviewed
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  • 72
    Publication Date: 2024-05-23
    Description: Die Vereinten Nationen haben einen Vertrag zum Schutz der Hohen See verabschiedet. Um sein Potenzial für die globale Meerespolitik zu nutzen, sollten die EU und Deutschland ihr strategisches Engagement in diesem Forum jetzt planen, meinen Miranda Böttcher und Gerrit Hansen.
    Type: Report , NonPeerReviewed
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  • 73
    Publication Date: 2024-05-23
    Type: Book chapter , NonPeerReviewed
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  • 74
    Publication Date: 2024-05-23
    Description: Since net zero targets have become a keystone of climate policy, more thought is being given to actively removing carbon dioxide from the atmosphere while continuing to drastically reduce emissions. The ocean plays a major role in regulating the global climate by absorbing a large proportion of anthropogenic carbon dioxide emissions. As the challenges of land-based carbon dioxide removal (CDR) approaches are increasingly recognised, the ocean may become the new “blue” frontier for carbon removal and storage strategies in the EU and beyond. However, the ocean is not an “open frontier”; rather, it is a domain of overlapping and sometimes conflicting rights and obligations. There is a tension between the sovereign right of states to use ocean resources within their exclusive economic zones and the international obligation to protect the ocean as a global commons. The EU and its Member States need to clarify the balance between the protection and use paradigms in ocean governance when considering treating the ocean as an enhanced carbon sink or storage site. Facilitating linkages between the ongoing review of the Marine Strategy Framework Directive and the establishment of the Carbon Removal Certification Framework could help pave the way for debate about trade-offs and synergies in marine ecosystem protection and use.
    Type: Article , NonPeerReviewed
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  • 75
    Publication Date: 2024-05-23
    Description: Climate policy in the European Union (EU) and Germany changed significantly with the adoption of net-zero emissions targets. A key new development is the growing importance of carbon management. The umbrella term includes not only the capture and storage of CO2 (carbon capture and storage, CCS), but also CO2 capture and utilisation (carbon capture and utilisation, CCU) as well as the removal of CO2 from the atmosphere (carbon dioxide removal, CDR). It is important to provide clarity when differentiating between these approaches and identifying their relation to so- called residual emissions and hard-to-abate emissions. This is particularly important because it will determine the overall ambition of climate policy as well as shape future policy designs and their distributional impacts. Current policy and legislative processes should ensure that carbon management does not delay the phase-out of fossil fuels. New policy initiatives present an opportunity to actively shape the interface between ambitious climate and industrial policy.
    Type: Report , NonPeerReviewed
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  • 76
    Publication Date: 2024-05-23
    Description: The implementation of the new net emission targets for 2030 and 2050 as part of the European Green Deal is moving the deliberate removal of CO 2 from the atmosphere up the agendas of political decision-makers. In its latest report, the Intergovernmen- tal Panel on Climate Change (IPCC) also recently reiterated that net-zero targets can- not be achieved without the deployment of carbon dioxide removal (CDR) methods. The political debate in the European Union (EU) about CDR has changed rapidly in recent years, with almost all political actors now calling for a new regulatory frame- work for CDR to become an integral building block of EU climate policy. However, fundamental conflicts are brewing over the question as to which removal methods and policy instruments should be implemented and which priorities should be set. There are signs of emerging political alliances on the EU level that will shape the Fit- for-55 legislation in the short term and pre-structure the debate on the design of climate policy between 2030 and 2040.
    Type: Report , NonPeerReviewed
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  • 77
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    Wissenschaftliche Auswertungen in Kooperation mit GEO Magazin
    Publication Date: 2024-05-23
    Description: Sollen wir Climate Engineering (CE) betreiben? Was spricht dafür und was dagegen? Antworten auf diese Fragen müssen empirisch informiert sein. Um mehr zu tun als das Machbare zu benennen, müssen sie sich aber auch mit Fragen der Moral auseinandersetzen, solchen nach Pflichten, Normen und Werten. In diesem Beitrag stellen wir 9 Thesen zur Ethik von CE auf. Wir diskutieren, welche ethischen Aspekte besonders wichtig, welche Chancen und Risiken von CE moralisch besonders bedeutsam sind, und was die Debatte um CE über uns aussagt. Summary Nine theses on the morality of climate engineering: Should we engineer the climate? What speaks in favour of doing it and what against? Answers to these questions must be based in empirical science. But they must also engage with moral questions – those about duties, norms and values – if they want to do more than simply name what is feasible. In this contribution we defend 9 theses on the ethics of climate engineering (CE). We discuss which ethical aspects are of particular importance, what opportunities and risk matter most from a moral point of view, and how the debate on CE reflects upon us. Resumen Nueve tesis sobre la moralidad de la ingeniería climática: ¿Deberíamos aplicar la ingeniería climática (EC)? ¿Qué está a favor y qué en contra? Las respuestas a estas preguntas deben basarse en datos empíricos. Pero para hacer algo más que afirmar lo que es factible, también deben abordar cuestiones de moralidad, de obligaciones, normas y valores. En este documento presentamos 9 tesis sobre la ética de la EC. Debatimos qué aspectos éticos son especialmente importantes, qué oportunidades y riesgos de la EC son moralmente significativos y qué dice de nosotros el debate sobre la EC.
    Type: Book chapter , NonPeerReviewed
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  • 78
    Publication Date: 2024-05-23
    Description: Es werden mögliche Beiträge geologischer und mariner Kohlenstoffspeicher für die Vermeidung von CO2-Emissionen in die Atmosphäre oder für die Entnahme von bereits emittiertem CO2 aus der Atmosphäre vorgestellt. Neben der Einlagerung von CO2 in geologischen Speichern unter Land und unter dem Meeresboden werden eine forcierte CO2-Entnahme aus der Atmosphäre und Abgabe in den Ozean durch Erhöhung der Alkalinität, durch Ozeandüngung und durch das Management vegetationsreicher Küstenökosysteme untersucht. Alle Optionen können sowohl global als auch aus deutscher Perspektive eine Rolle für das Erreichen der Klimaziele spielen. Umweltverträglichkeit, Permanenz der Speicherung sowie infrastrukturelle und rechtliche Voraussetzungen, gesellschaftliche Akzeptanz und wirtschaftliche Realisierbarkeit bedürfen für alle Ansätze weiterer Klärung, bevor hieraus realisierbare Optionen werden können.
    Type: Book chapter , NonPeerReviewed
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  • 79
    Publication Date: 2024-05-23
    Description: To limit global warming to 1.5°C, vast amounts of CO2 will have to be removed from the atmos‐ phere via Carbon Dioxide Removal (CDR). Enhancing the CO2 sequestration of ecosystems will require not just one approach but a portfolio of CDR options, including so‐called nature‐based approaches alongside CDR options that are perceived as more technical. Creating a CDR “supply curve” would however imply that all carbon removals are considered to be perfect substitutes. The various co‐benefits of nature‐based CDR approaches militate against this. We discuss this aspect of nature‐based solutions in connection with the enhancement of blue carbon ecosys‐ tems (BCE) such as mangrove or seagrass habitats. Enhancing BCEs can indeed contribute to CO 2 sequestration, but the value of their carbon storage is low compared to the overall contri‐ bution of their ecosystem services to wealth. Furthermore, their property rights are often un‐ clear, i.e. not comprehensively defined or not enforced. Hence, payment schemes that only compensate BCE carbon sequestration could create tradeoffs at the expense of other im‐ portant, often local, ecosystem services and might not result in socially optimal outcomes. Ac‐ cordingly, one chance for preserving and restoring BCEs lies in the consideration of all services in potential compensation schemes for local communities. Also, local contexts, management structures, and benefit‐sharing rules are crucial factors to be considered when setting up inter‐ national payment schemes to support the use of BCEs and other nature‐ or ecosystem‐based CDR. However, regarding these options as the only hope of achieving more CDR will very prob‐ ably not bring about the desired outcome, either for climate mitigation or for ecosystem preser‐ vation. Unhalted degradation, in turn, will make matters worse due to the large amounts of stored carbon that would be released. Hence, countries committed to climate mitigation in line with the Paris targets should not hide behind vague pledges to enhance natural sinks for re‐ moving atmospheric CO2 but commit to scaling up engineered CDR.
    Type: Report , NonPeerReviewed
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  • 80
    Publication Date: 2024-05-23
    Type: Report , NonPeerReviewed
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  • 81
    Publication Date: 2024-05-23
    Description: Since net-zero greenhouse gas emissions targets have become a keystone of European and German climate policy, a debate about the need to actively remove carbon dioxide from the atmosphere in addition to drastically reducing emissions has emerged. Although still relatively scarce, empirical studies on the emergence of carbon dioxide removal (CDR) on the political agenda have shown that variations in the constellations and positions of policy-relevant actors play a key role in shaping patterns of CDR policymaking. The German and wider European Union (EU) CDR policy space is emergent, and political actors are just beginning to position themselves. Building on our previous work which established a typology of CDR policy integration patterns and developed a discourse analytical framework for mapping CDR-policy-relevant speaker positions, we present the first fine-grained empirical reconstruction of CDR-policy-relevant actors and their positions in the German context. Our analytical approach aims to improve understanding of patterns in CDR policymaking by showing that on the EU, national, and subnational levels, a multitude of institutional actors may adopt differing positions as the CDR policy space evolves. In addition to identifying fine-grained ‘ideal types’ of positions that policy actors may adopt in the formative phase of German CDR policy, our analysis provides an empirical ‘map’ of CDR policy-relevant actors and explores hypotheses about emerging discourse coalitions and potential conflict cleavages.
    Type: Article , PeerReviewed
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  • 82
    Publication Date: 2024-05-23
    Description: Highlights • Climate engineering presents a novel challenge for global environmental governance • Institutional and discursive structures co-shape global environmental governance • A lack of joint analyses of both structures impedes understanding of governance emergence • A joint neo-institutionalist and post-structuralist analysis addresses this gap • Varying structures shape differing climate engineering governance decisions in several forums Abstract The Anthropocene is giving rise to novel challenges for global environmental governance. The barriers and opportunities shaping the ways in which some of these complex environmental challenges become governable on the global level are of increasing academic and practical relevance. In this article, we bring neo-institutionalist and post-structuralist perspectives together in an innovative framework to analyse how both institutional and discursive structures together bound and shape the global governance opportunities which become thinkable and practicable in the face of new global environmental challenges. We apply this framework to explore how governance of climate engineering – large scale, deliberate invention into the global climate system – is being shaped by discursive and institutional structures in three international forums: The London Convention and its Protocol, the Convention on Biological Diversity, and the United Nations Environment Assembly. We illustrate that the ‘degree of fit’ between discursive and institutional structures made climate engineering (un)governable in each of these forums. Furthermore, we find that the ‘type of fit’ set the discursive and institutional conditions of possibility for what type of governance emerged in each of these cases. Based on our findings, we critically discuss the implications for the future governance of climate engineering at the global level.
    Type: Article , PeerReviewed
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  • 83
    Publication Date: 2024-05-23
    Description: Ocean alkalinity enhancement (OAE) seeks to increase the alkalinity of seawater for carbon dioxide removal (CDR). Following numerous propositions to trial, test, or upscale OAE for CDR, multiple social considerations have begun to be identified. To ensure that OAE research is responsible (is attentive to societal priorities) and successful (does not prematurely engender widespread social rejection), it will be critical to understand how OAE might be perceived as risky or controversial and under what conditions it might be regarded by relevant social groups as most worthy of exploration. To facilitate the answering of these questions, this chapter does the following: (1) characterizes what is known to date about public perceptions of OAE, (2) provides methodological suggestions on how to conduct social science research and public engagement to accompany OAE field research, and (3) addresses how knowledge gained from social research and public engagement on OAE can be integrated into ongoing scientific, siting, and communications work.
    Type: Article , PeerReviewed
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  • 84
    Publication Date: 2024-05-23
    Description: Given the clear need to inform societal decision-making on the role marine Carbon Dioxide Removal (mCDR) can play in solving the climate crisis, it is imperative that researchers begin to answer questions about its effectiveness and impacts. Yet overly hasty deployment of new ocean-based climate interventions risks harm to communities and ecosystems and could jeopardize public perception of the field as a whole. In addition, the harms, risks and benefits of mCDR efforts are unlikely to be evenly distributed. Unabated, climate change could have a devastating impact on global ecosystems and human populations, and the impacts of mCDR should be contemplated in this context. This Code of Conduct exclusively applies to mCDR research and does not attempt to put any affiliated risk in the context of the risk of delaying climate action. Its purpose is to ensure that the impacts of mCDR research activities themselves are adequately understood and accounted for as they progress. It provides a roadmap of processes, procedures, and activities that project leads should follow to ensure that decisions regarding whether, when, where, and how to conduct mCDR research are informed by relevant ethical, scientific, economic, environmental, and regulatory considerations.
    Type: Report , NonPeerReviewed
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  • 85
    Publication Date: 2024-05-23
    Description: A global, independent scientific assessment of Carbon Dioxide Removal
    Type: Report , NonPeerReviewed
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  • 86
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    Stiftung Wissenschaft und Politik
    Publication Date: 2024-05-23
    Type: Book , NonPeerReviewed
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  • 87
    Publication Date: 2024-05-22
    Description: 〈title xmlns:mml="http://www.w3.org/1998/Math/MathML"〉Abstract〈/title〉〈p xmlns:mml="http://www.w3.org/1998/Math/MathML" xml:lang="en"〉Mineral dust is one of the most abundant atmospheric aerosol species and has various far‐reaching effects on the climate system and adverse impacts on air quality. Satellite observations can provide spatio‐temporal information on dust emission and transport pathways. However, satellite observations of dust plumes are frequently obscured by clouds. We use a method based on established, machine‐learning‐based image in‐painting techniques to restore the spatial extent of dust plumes for the first time. We train an artificial neural net (ANN) on modern reanalysis data paired with satellite‐derived cloud masks. The trained ANN is applied to cloud‐masked, gray‐scaled images, which were derived from false color images indicating elevated dust plumes in bright magenta. The images were obtained from the Spinning Enhanced Visible and Infrared Imager instrument onboard the Meteosat Second Generation satellite. We find up to 15% of summertime observations in West Africa and 10% of summertime observations in Nubia by satellite images miss dust plumes due to cloud cover. We use the new dust‐plume data to demonstrate a novel approach for validating spatial patterns of the operational forecasts provided by the World Meteorological Organization Dust Regional Center in Barcelona. The comparison elucidates often similar dust plume patterns in the forecasts and the satellite‐based reconstruction, but once trained, the reconstruction is computationally inexpensive. Our proposed reconstruction provides a new opportunity for validating dust aerosol transport in numerical weather models and Earth system models. It can be adapted to other aerosol species and trace gases.〈/p〉
    Description: Plain Language Summary: Most dust and sand particles in the atmosphere originate from North Africa. Since ground‐based observations of dust plumes in North Africa are sparse, investigations often rely on satellite observations. Dust plumes are frequently obscured by clouds, making it difficult to study the full extent. We use machine‐learning methods to restore information about the extent of dust plumes beneath clouds in 2021 and 2022 at 9, 12, and 15 UTC. We use the reconstructed dust patterns to demonstrate a new way to validate the dust forecast ensemble provided by the World Meteorological Organization Dust Regional Center in Barcelona, Spain. Our proposed method is computationally inexpensive and provides new opportunities for assessing the quality of dust transport simulations. The method can be transferred to reconstruct other aerosol and trace gas plumes.〈/p〉
    Description: Key Points: 〈list list-type="bullet"〉 〈list-item〉 〈p xml:lang="en"〉We present the first fast reconstruction of cloud‐obscured Saharan dust plumes through novel machine learning applied to satellite images〈/p〉〈/list-item〉 〈list-item〉 〈p xml:lang="en"〉The reconstruction algorithm utilizes partial convolutions to restore cloud‐induced gaps in gray‐scaled Meteosat Second Generation‐Spinning Enhanced Visible and Infrared Imager Dust RGB images〈/p〉〈/list-item〉 〈list-item〉 〈p xml:lang="en"〉World Meteorological Organization dust forecasts for North Africa mostly agree with the satellite‐based reconstruction of the dust plume extent〈/p〉〈/list-item〉 〈/list〉 〈/p〉
    Description: GEOMAR Helmholtz Centre for Ocean Research Kiel
    Description: University of Cologne
    Description: https://doi.org/10.5281/zenodo.6475858
    Description: https://github.com/tobihose/Masterarbeit
    Description: https://dust.aemet.es/
    Description: https://ads.atmosphere.copernicus.eu/cdsapp#!/dataset/cams-global-reanalysis-eac4?tab=overview
    Description: https://navigator.eumetsat.int/product/EO:EUM:DAT:MSG:DUST
    Description: https://navigator.eumetsat.int/product/EO:EUM:DAT:MSG:CLM
    Description: https://doi.org/10.5067/KLICLTZ8EM9D
    Description: https://disc.gsfc.nasa.gov/datasets?project=MERRA-2
    Description: https://doi.org/10.5067/MODIS/MOD08_D3.061
    Description: https://doi.org/10.5067/MODIS/MYD08_D3.061
    Description: https://doi.org/10.5281/ZENODO.8278518
    Keywords: ddc:551.5 ; mineral dust ; North Africa ; MSG SEVIRI ; machine learning ; cloud removal ; satellite remote sensing
    Language: English
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  • 88
    Publication Date: 2024-05-22
    Description: 〈title xmlns:mml="http://www.w3.org/1998/Math/MathML"〉ABSTRACT〈/title〉〈p xmlns:mml="http://www.w3.org/1998/Math/MathML" xml:lang="en"〉During the Middle Devonian, reef growth reached an acme, and corals and stromatoporoids colonized depositional niches commonly considered unfavourable for reefal organisms. This paper documents the detailed facies architecture and palaeoecology of a stratigraphically thin (〈italic toggle="no"〉ca〈/italic〉 12 m, ‘carpet reef’), lower Givetian reefal body exposed along the walls and ceilings of the labyrinthine passages in the Klutert Cave in western Germany. The cave exposures (〈italic toggle="no"〉ca〈/italic〉 26 000 m〈sup〉2〈/sup〉 of rock surface) and data from short cores, neighbouring caves and outcrops document the growth and demise of an autoparabiostrome. The reef forms part of a parasequence with a lower carbonate and an upper clastic unit, bounded by flooding surfaces. Despite the comparatively small study area (〈italic toggle="no"〉ca〈/italic〉 1 km〈sup〉2〈/sup〉), the exceptional exposure quality reveals facies changes over relatively short distances both vertical and lateral. The sedimentary matrix of the reefal build‐up contains between 20 to 95 wt.‐% of clay and quartz of silt to sand fraction. Based on this observation, the corals and stromatoporoids thrived in murky waters and under sediment‐stressed conditions. Stromatoporoids, for example, display irregular ragged flanks, a feature that is in agreement with a sediment‐stressed environment. No evidence of reduced growth rates, decreased calcification rates, or lower numbers of species is found. In fact, coral diversity and density are highest within one of the two biostromal units that show peak clastic matrix values, indicating a remarkable adaptation of reef builders to sediment‐stressed conditions. The initial settlement of rugose phaceloid corals took place on a mixed clastic–carbonate substrate (the basal flooding surface). Up‐section, a succession of coral–stromatoporoids is present that is here described in great detail. Reef collapse occurred when much of the accommodation space was filled, and argillaceous sediments suffocated stromatoporoids and corals in a protected, low‐energy environment.〈/p〉
    Description: Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659
    Keywords: ddc:560 ; Biostrome ; corals ; Givetian ; mixed clastic–carbonate system ; reef model ; stromatoporoids
    Language: English
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  • 89
    Publication Date: 2024-05-22
    Description: 〈title xmlns:mml="http://www.w3.org/1998/Math/MathML"〉Abstract〈/title〉〈p xmlns:mml="http://www.w3.org/1998/Math/MathML" xml:lang="en"〉The movement of active dunes is tightly linked to climatic conditions (e.g., wind regime, temperature and precipitation) as well as human influence (e.g., grazing, dune fixation and greening). Dune migration rates can be studied to draw conclusions of changing wind conditions over time. The Gonghe Basin (GB), located on the north‐eastern Tibetan Plateau (TP), offers a good testing ground for these assumptions. The intramontane basin is highly influenced by two major wind regimes: the mid‐latitude Westerlies and the East Asian summer monsoon. To investigate environmental changes, this study combines optical remote sensing techniques with climatic datasets. High‐resolution satellite images of the last five decades, such as CORONA KH‐4B, are used to map dunes and calculate their respective migration rates. Further, height information was extracted as well. Climatic changes from the ERA‐5 reanalysis dataset and normalized difference vegetation index (NDVI) values were processed alongside. Relating the dunes' surface processes to climate model data shows an accordance between slowing migration, expanding vegetation and a decrease in sand drift potential. From 1968 to present time, an average dune migration rate of 7.3 m a〈sup〉−1〈/sup〉 was extracted from the satellite images, with an overall reduction of −1.81 m a〈sup〉−1〈/sup〉. The resultant drift potential (RDP) values for the GB are calculated to be below 10 m〈sup〉3〈/sup〉 s〈sup〉−3〈/sup〉 with a spatial decrease, following a direction from the NW to the SE, fitting well with a corresponding decrease in the migration rates. Our results indicate a good agreement between the development of aeolian landforms and the ERA‐5 climate reanalysis model data, even in a high‐altitude setting with complex topography, which is known to influence such datasets.〈/p〉
    Description: 〈p xmlns:mml="http://www.w3.org/1998/Math/MathML" xml:lang="en"〉We investigate climatic changes of the past 5 decades in the Gonghe Basin by using a wide range of remote sensing data. Era‐5 data is compared with dune migration rates. The dunes' behaviour is very well represented within the ERA‐5 data and shows a slowing migration over the past five decades. This fits well to climatic developments, like increasing precipitation and temperature. Sand drift potential was calculated and interpolated to pinpoint resultant drift potential (RDP) values to individual barchans. 〈boxed-text position="anchor" content-type="graphic" id="esp5651-blkfxd-0001" xml:lang="en"〉 〈graphic position="anchor" id="jats-graphic-1" xlink:href="urn:x-wiley:01979337:media:esp5651:esp5651-toc-0001"〉 〈/graphic〉 〈/boxed-text〉〈/p〉
    Description: Federal Ministry of Education and Research of Germany (BMBF)
    Description: National Key Research and Development Program of China http://dx.doi.org/10.13039/501100012166
    Keywords: ddc:551.3 ; climate change ; CORONA KH‐4B ; dunes ; ERA‐5 ; satellite remote sensing ; Tibetan Plateau
    Language: English
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  • 90
    Publication Date: 2024-05-22
    Description: 〈title xmlns:mml="http://www.w3.org/1998/Math/MathML"〉Abstract〈/title〉〈p xmlns:mml="http://www.w3.org/1998/Math/MathML" xml:lang="en"〉Erzgebirge ultrahigh‐pressure (UHP) garnet peridotite includes scarce layers of garnet pyroxenite, nodules of garnetite and, very rarely, of eclogite. Peridotite‐hosted eclogite shows the same subalkali‐basaltic bulk rock composition, mineral assemblage and peak conditions as gneiss‐hosted eclogite present in the same UHP unit. Garnetite has considerably more Mg, moderately enhanced Ca and Fe and significantly lower contents of Na, Ti, P, K and Si than eclogite, whereas Al is very similar. In addition, the compatible trace elements (Ni, Co, Cr, V) are elevated and most incompatible elements (Zr, Hf, Y, Sr, Rb and rare Earth elements [REE]) are depleted in garnetite relative to eclogite. In contrast to other large ion lithophile elements (LILEs), Pb (+121%) and Ba (+83%) are strongly enriched. The REE patterns of garnetite are characterized by depletion of light and heavy REE and a medium REE hump indicative of metasomatism, features being absent in eclogite. An exceptional garnetite sample shows an REE distribution similar to that of eclogite. Garnetite is interpreted to have formed from the same, but metasomatically altered, igneous protolith as eclogite. Except for Ba and Pb, the chemical signature of garnetite is explained best by metasomatic changes of its basaltic protolith caused by serpentinization of the host peridotite. Garnetite is chemically similar to basaltic rodingite/metarodingite. Although rodingite is commonly more enriched in Ca, there are also examples with moderately enhanced Ca matching the composition of Erzgebirge garnetite. Limited Ca metasomatism is attributed to the preservation of Ca in peridotite during hydrous alteration. This can be explained by incomplete serpentinization favouring metastable survival of the original clinopyroxene. In this case, most Ca is retained in peridotite and not available for infiltration and metasomatism of the garnetite protolith. This inescapable consequence is supported by the fact that clinopyroxene is part of the garnet peridotite UHP assemblage, which would not be the case if Ca had been removed from the protolith prior to high‐pressure metamorphism. The enrichment of compatible elements in garnetite is attributed to decomposition of peridotitic olivine (Ni, Co) and spinel (Cr, V) during serpentinization. Enrichment of Ba and Pb contrasts the behaviour of other LILEs and is ascribed to dehydration of the serpentinized peridotite (deserpentinization). This requires two separate stages of metasomatism: (1) intense chemical alteration of the basaltic garnetite precursor, together with serpentinization of peridotite at the ocean floor or during incipient subduction; and (2) prograde metamorphism and dehydration of serpentinite during continued subduction, thereby releasing Pb–Ba‐rich fluids that reacted with associated metabasalt. Finally, subduction to >100 km and UHP metamorphism of all lithologies led to formation of garnetite, eclogite and garnet pyroxenite hosted by co‐facial garnet peridotite as observed in the Erzgebirge.〈/p〉
    Description: Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659
    Keywords: ddc:552.4 ; Erzgebirge ; garnetite ; rodingitization ; serpentinization ; UHP metamorphism
    Language: English
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  • 91
    Publication Date: 2024-05-22
    Description: 〈title xmlns:mml="http://www.w3.org/1998/Math/MathML"〉Abstract〈/title〉〈p xmlns:mml="http://www.w3.org/1998/Math/MathML" xml:lang="en"〉Due to the inherently fluid‐mobile nature of W, the 〈sup〉182〈/sup〉W record of the early Earth may have been obscured by fluid‐induced mobilization of W. To investigate W mobilization in Archean greenstone sequences, we analyzed 〈sup〉182〈/sup〉W isotope systematics and major and trace element concentrations in samples from the 3.53 Ga old Onverwacht Group of the Kaapvaal Craton (South Africa) and the >3.51 Ga old Badampahar Group of the Singhbhum Craton (India). Our results for mafic and ultramafic metavolcanic rocks show W/Th ratios significantly higher than primary magmatic values, which suggests fluid‐induced W enrichment. Samples least affected by secondary W enrichment (W/Th 〈 0.26) show no resolvable W isotope anomalies from modern mantle values in both cratons. Samples from the Kaapvaal Craton with elevated W/Th exhibit deficits in 〈sup〉182〈/sup〉W as low as −8.1 ± 4.3 ppm compared to the modern mantle. Covariations of μ〈sup〉182〈/sup〉W with W/Th, and Ce/Pb suggest that negative isotope signatures were introduced during secondary fluid‐mediated processes. The enrichment of W is most evident in altered ultramafic rocks comprising serpentine, resulting in additional covariations between MgO, LOI, and W/Th. The W isotope composition of serpentinized komatiites reflects the composition of younger intruding granitoids. We therefore infer the latter as a possible source of W‐rich fluids. The Badampahar Group samples exhibit little W isotope variability. A well‐resolved 〈sup〉182〈/sup〉W deficit of −6.2 ± 2.9 ppm was determined in a single komatiite sample, which indicates an unknown fluid source, currently not represented in any other unit of the Singhbhum Craton.〈/p〉
    Description: Plain Language Summary: The tungsten (W) isotope composition of ancient rocks can be used to trace processes that occurred during Earth's early evolution. However, interactions between rocks and fluids may alter the W concentration and therefore influence the interpretation of W isotope data. To identify the source of such fluids and the processes by which they affect the W isotope composition of rocks, we analyzed ancient rock samples from South Africa and India. The isotope composition of rocks with a low W concentration reflects that of the modern Earth. Therefore, they do not trace the processes that occurred during Earth's early evolution. Samples from South Africa with untypically high W concentrations show a different isotopic composition. The variation in the W isotope signature correlates with other chemical indices that are susceptible to modification by fluid‐related processes. This shows that the W within the rocks is derived from an external fluid source and not from their original magmatic source. Samples with the highest W enrichment have a similar isotope composition as spatially associated intrusive rocks. By inference, the latter likely represent the source of W‐rich fluids. The samples from India show similar enrichment in W, indicating similar fluid‐related processes and W sources at both localities.〈/p〉
    Description: Key Points: 〈list list-type="bullet"〉 〈list-item〉 〈p xml:lang="en"〉The magmatic sources of metavolcanic rocks from the Onverwacht Group and the Badampahar Group do not exhibit W isotope anomalies〈/p〉〈/list-item〉 〈list-item〉 〈p xml:lang="en"〉Negative W isotope signatures in the Onverwacht Group are likely derived from fluids sourced from younger intrusive granitoids〈/p〉〈/list-item〉 〈list-item〉 〈p xml:lang="en"〉Felsic intrusive rocks are a major source of W‐rich fluids in Paleoarchean greenstone units〈/p〉〈/list-item〉 〈/list〉 〈/p〉
    Description: Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659
    Description: https://doi.org/10.5880/digis.2023.005
    Keywords: ddc:551.9 ; fluid‐mobility ; Kaapvaal ; Singhbhum ; 182W ; tungsten isotopes
    Language: English
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  • 92
    Publication Date: 2024-05-22
    Description: 〈title xmlns:mml="http://www.w3.org/1998/Math/MathML"〉Abstract〈/title〉〈p xmlns:mml="http://www.w3.org/1998/Math/MathML" xml:lang="en"〉Coastal protection in the form of dike constructions has a long history at the German North Frisian coast dating back to the High Middle Ages. As the vast majority of the dikes built prior to the devastating storm surges of the Middle Ages have been irretrievably destroyed, mostly sparse remains and only a few well preserved of these medieval dikes are found along the German North Frisian coast and within the Wadden Sea. Not all details of their construction and dimensions are yet understood. In the present case study, we investigate the historical Schardeich on the island of Pellworm in the German North Sea in a noninvasive way using shear waves (SH‐waves). For the data interpretation, we applied a combination of seismic full waveform inversion and classical seismic reflection imaging to determine the interior structure of the dike and its underlying layers at the highest possible resolution. The results obtained on land are compared with dike remains found in the tidal flats. These remains show up in marine seismic sections as characteristic reflections, which probably represent a compaction layer caused by the load of the former dike. For ground truthing, we compare the seismic results with internal dike structures found in nearby excavations. The comparison highlights that FWI is a reliable tool for near‐surface archaeological prospecting. We find that SH‐wave FWI provides decimetre‐scale velocity and density models that allow, together with the seismic reflection section, to determine distinct construction phases of the dike. The investigated dike further shows a depression at base level of about 0.75 m, which is of the same order as observed for the dike base reflections in the tidal flats. Transferring these findings to the dike remains mapped in the tidal flats, we derive a height of the former dike from 2.2 to 4.4 m.〈/p〉
    Description: Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659
    Keywords: ddc:622.1592 ; archaeogeophysics ; high‐resolution seismic reflection imaging ; seismic full waveform inversion ; shear‐wave seismic
    Language: English
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  • 93
    Publication Date: 2024-05-22
    Description: 〈title xmlns:mml="http://www.w3.org/1998/Math/MathML"〉Abstract〈/title〉〈p xmlns:mml="http://www.w3.org/1998/Math/MathML" xml:lang="en"〉Regardless of the steady increase of computing power during the last decades, numerical models in a 3D spherical shell are only used in specific setups to investigate the thermochemical convection in planetary interiors, while 2D geometries are typically favored in most exploratory studies involving a broad range of parameters. The 2D cylindrical and the more recent 2D spherical annulus geometries are predominantly used in this context, but the extent to how well they reproduce the 3D spherical shell results in comparison to each other and in which setup has not yet been extensively investigated. Here we performed a thorough and systematic study in order to assess which 2D geometry reproduces best the 3D spherical shell. In a first set of models, we investigated the effects of the geometry on thermal convection in steady‐state setups while varying a broad range of parameters. Additional thermal evolution models of three terrestrial bodies, namely Mercury, the Moon, and Mars, which have different interior structures, were used to compare the 2D and 3D geometries. Our investigations show that the 2D spherical annulus geometry provides results closer to models in a 3D spherical shell compared to the 2D cylindrical geometry. Our study indicates where acceptable differences can be expected when using a 2D instead of a 3D geometry and where to be cautious when interpreting the results.〈/p〉
    Description: Plain Language Summary: In geodynamic modeling, numerical models are used in order to investigate how the interior of a terrestrial planet evolves from the earliest stage, after the planetary formation, up to present day. Often, the mathematical equations that are used to model the physical processes in the interior of rocky planets are discretized and solved using geometric meshes. The most commonly applied geometries are the 3D spherical shell, the 2D cylinder, and the 2D spherical annulus. While being the most accurate and realistic, the 3D geometry is expensive in terms of computing power and time of execution. On the other hand, 2D geometries provide a reduced accuracy but are computationally faster. Here we perform an extensive comparison between 2D and 3D geometries in scenarios of increasing complexity. The 2D spherical annulus geometry shows much closer results to the 3D spherical shell when compared to the 2D cylinder and should be given preference in 2D modeling studies.〈/p〉
    Description: Key Points: 〈list list-type="bullet"〉 〈list-item〉 〈p xml:lang="en"〉Interior dynamics models using the 2D spherical annulus geometry match the results of a 3D spherical shell better than the 2D cylinder〈/p〉〈/list-item〉 〈list-item〉 〈p xml:lang="en"〉The difference between 2D and 3D geometries decreases when models are heated from below by the core and from within by radioactive elements〈/p〉〈/list-item〉 〈list-item〉 〈p xml:lang="en"〉The 2D spherical annulus shows negligible differences to 3D for the thermal evolution of Mercury and the Moon, and acceptable values for Mars〈/p〉〈/list-item〉 〈/list〉 〈/p〉
    Description: Ministry of Science, Research and the Arts Baden‐Württemberg
    Description: Federal Ministry of Education and Research
    Description: https://doi.org/10.5281/zenodo.8047757
    Keywords: ddc:523 ; mantle convection ; thermal evolution ; spherical annulus ; Mars ; Moon ; Mercury
    Language: English
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  • 94
    Publication Date: 2024-05-22
    Description: 〈title xmlns:mml="http://www.w3.org/1998/Math/MathML"〉Abstract〈/title〉〈p xmlns:mml="http://www.w3.org/1998/Math/MathML" xml:lang="en"〉As projected by multiple climate models, short‐duration heavy precipitation events (SDHPEs) are expected to intensify particularly quickly under the changing climate posing substantial risk to natural and human systems. Yet over the years, SDHPEs have received less scientific attention than long‐duration heavy precipitation events (LDHPEs), mainly due to the limitations of measurement systems. Our aim is to provide insight into spatial and temporal variability of SDHPEs detected by the radar network of the 〈italic toggle="no"〉Deutscher Wetterdienst〈/italic〉 (DWD) in Germany from 2001 to 2020 as well as to explore their links to circulation patterns (CPs). The study is based on the Catalogue of Radar‐based heavy Rainfall Events (CatRaRE) generated using reprocessed gauge‐adjusted data of the DWD radar network as well as a new numerical method for classifying CPs over Central Europe called “〈italic toggle="no"〉Großwetterlagen〈/italic〉 for Reanalyses” (GWL‐REA). The results have demonstrated that SDHPEs, which are defined based on either locally valid precipitation values with a return period of 5 years (CatRaRE T5) or absolute precipitation values equal to DWD Warning Level 3 (CatRaRE W3), are common phenomena occurring most frequently in the afternoon hours of the summer season. They constitute up to 90% of all heavy precipitation events included in the catalogues covering relatively small areas—the median area of SDHPEs ranges from 22 km〈sup〉2〈/sup〉 (CatRaRE T5) to 24 km〈sup〉2〈/sup〉 (CatRaRE W3), while the median area of LDHPEs ranges from 175 km〈sup〉2〈/sup〉 (CatRaRE W3) to 184 km〈sup〉2〈/sup〉 (CatRaRE T5). As compared to LDHPEs, SDHPEs are generated by a wider spectrum of circulation conditions, including not only cyclonic but also anticyclonic CPs. In the warm season, the anticyclonic CPs, often accompanied by air mass advection from the south, can induce high thermal instability leading to the development of relatively small, isolated convective cells, which often cannot be captured by rain gauge stations.〈/p〉
    Description: Federal Ministry for Digital and Transport (BMDV)
    Description: https://www.dwd.de/DE/leistungen/catrare/catrare.html
    Keywords: ddc:551.6 ; CatRaRE ; circulation patterns ; GWL‐REA ; heavy precipitation events ; long‐duration precipitation ; radar data ; short‐duration precipitation
    Language: English
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  • 95
    Publication Date: 2024-05-22
    Description: Most seals (pinnipeds) disperse from centralised terrestrial haul out sites to forage at sea which results in great intraspecific competition for prey. This competition may be reduced by gender-specific differences in depth use, something which should be enhanced by sexual dimorphism because diving ability is a function of body size. This thesis discusses the sex-specific behaviour of harbour seals (Phoca vitulina) in the North Sea. The aim was to determine the extent to which this species might have gender-dependent foraging strategies and, where apparent, to identify possible causes. The diving behaviour of six males and six females was analysed using animal-attatched data loggers (dead reckoners). With a weight of 73 kg (SD = 10) the equipped males were approx. 30 % heavier than females at 55 kg (SD = 8). All seals spent most of their time at sea (males 75.8 %, females 88.1 %) and perfmmed mainly U-shaped dives (ea. 80 %). The maximum recorded dive depth was 43 m for the males and 28 m for the females. Maximum dive duration lasted to 10 minuntes for females and 16 minutes for males. Mean trip duration was 44.1 h (SD = 65.5) for males and 46.8 h for females (SD = 35). Both genders showed significant correlations between dive duration and dive depth, as well as the durations of the descent, bottom and ascent phase and dive depth. However, there were no significant differences either in diving capabilities or in the foraging efficiency of the two sexes. An effect of body size on the diving capabilities of the seals could not been demonstrated. This indicates that the seals' diving capabilities in the North Sea are mainly determined by the bathymetry. Possible sex-specific differences might not be revealed because the seals do not reach their physiological limits in the shallow North Sea. Also, the large variance in the data as well as the small sample size mad it difficult to identify gender-specific differences. Tests of statistical power reveal that data from a total of 262 seals would be needed as an adequate sample size to determine with any certainty whether inter-sex differences occur.
    Type: Thesis , NonPeerReviewed
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  • 96
    Publication Date: 2024-05-22
    Description: Orbital cyclicity is a fundamental pacemaker of Earth’s climate system. The Newark–Hartford Basin (NHB) lake sediment record of eastern North America contains compelling geologic expressions of this cyclicity, reflecting variations of climatic conditions in tropical Pangea during the Late Triassic and earliest Jurassic (~233 to 199 Ma). Climate modeling enables a deeper mechanistic understanding of Earth system modulation during this unique greenhouse and supercontinent period. We link major features of the NHB record to the combined climatic effects of orbital forcing, paleogeographic changes, and atmospheric p CO 2 variations. An ensemble of transient, orbitally driven climate simulations is assessed for nine time slices, three atmospheric p CO 2 values, and two paleogeographic reconstructions. Climatic transitions from tropical humid to more seasonal and ultimately semiarid are associated with tectonic drift of the NHB from ~ 5 ° N to 20 ° N . The modeled orbital modulation of the precipitation–evaporation balance is most pronounced during the 220 to 200 Ma interval, whereas it is limited by weak seasonality and increasing aridity before and after this interval. Lower p CO 2 at around 205 Ma contributes to drier climates and could have led to the observed damping of sediment cyclicity. Eccentricity-modulated precession dominates the orbitally driven climate response in the NHB region. High obliquity further amplifies summer precipitation through the seasonal shifts in the tropical rainfall belt. Regions with other proxy records are also assessed, providing guidance toward an integrated picture of global astronomical climate forcing in the Late Triassic and ultimately of other periods in Earth history.
    Type: Article , PeerReviewed
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  • 97
    Publication Date: 2024-05-22
    Description: Data is an important foundation of scientific progress. It allows us to contrast hypotheses with observational evidence. Sharing and providing data openly have a long tradition in paleoenvironmental research, supported by repositories such as WDS-Paleo, PANGAEA,and Neotoma.
    Type: Article , NonPeerReviewed
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  • 98
    Publication Date: 2024-05-22
    Type: Article , NonPeerReviewed
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  • 99
    Publication Date: 2024-05-22
    Description: Observation‐based quantification of ocean carbon dioxide (CO 2 ) uptake relies on synthesis data sets such as the Surface Ocean CO 2 ATlas (SOCAT). However, the data collection effort has dramatically declined and the number of annual data sets in SOCATv2023 decreased by ∼35% from 2017 to 2021. This decline has led to a 65% increase (from 0.15 to 0.25 Pg C yr −1 ) in the standard deviation of seven SOCAT‐based air‐sea CO 2 flux estimates. Reducing the availability of the annual data to that in the year 2000 creates substantial bias (50%) in the long‐term flux trend. The annual mean CO 2 flux is insensitive to the seasonal skew of the SOCAT data and to the addition of the lower accuracy data set available in SOCAT. Our study highlights the need for sustained data collection and synthesis, to inform the Global Carbon Budget assessment, the UN‐led climate negotiations, and measurement, reporting, and verification of ocean‐based CO 2 removal projects. Plain Language Summary The Surface Ocean CO 2 ATlas (SOCAT) data set plays a crucial role in estimating the ocean carbon sink component of the Global Carbon Budget. However, the number of data sets available in SOCAT each year has drastically decreased since 2017. This study shows that the uncertainty in the data‐based ocean CO 2 flux estimate has increased by 65% due to this decline in data availability. The estimated fluxes, especially the long‐term flux trend, are remarkably affected by the data availability in SOCAT, reducing the reliability of ocean CO 2 uptake estimates in years and regions with sparse observations. Key Points Lower surface ocean f CO 2 data availability leads to higher uncertainty in data‐based estimates of ocean CO 2 uptake The long‐term trend in the ocean CO 2 flux increases by 1.5 times for subsequent years if the data availability is reduced to that in 2000 The annual mean CO 2 flux is not sensitive to the seasonal skew in the data and to the addition of low accuracy data
    Type: Article , PeerReviewed
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  • 100
    Publication Date: 2024-05-22
    Description: Ocean warming and species exploitation have already caused large‐scale reorganization of biological communities across the world. Accurate projections of future biodiversity change require a comprehensive understanding of how entire communities respond to global change. We combined a time‐dynamic integrated food web modeling approach (Ecosim) with previous data from community‐level mesocosm experiments to determine the independent and combined effects of ocean warming, ocean acidification and fisheries exploitation on a well‐managed temperate coastal ecosystem. The mesocosm parameters enabled important physiological and behavioral responses to climate stressors to be projected for trophic levels ranging from primary producers to top predators, including sharks. Through model simulations, we show that under sustainable rates of fisheries exploitation, near‐future warming or ocean acidification in isolation could benefit species biomass at higher trophic levels (e.g., mammals, birds, and demersal finfish) in their current climate ranges, with the exception of small pelagic fishes. However, under warming and acidification combined, biomass increases at higher trophic levels will be lower or absent, while in the longer term reduced productivity of prey species is unlikely to support the increased biomass at the top of the food web. We also show that increases in exploitation will suppress any positive effects of human‐driven climate change, causing individual species biomass to decrease at higher trophic levels. Nevertheless, total future potential biomass of some fisheries species in temperate areas might remain high, particularly under acidification, because unharvested opportunistic species will likely benefit from decreased competition and show an increase in biomass. Ecological indicators of species composition such as the Shannon diversity index decline under all climate change scenarios, suggesting a trade‐off between biomass gain and functional diversity. By coupling parameters from multilevel mesocosm food web experiments with dynamic food web models, we were able to simulate the generative mechanisms that drive complex responses of temperate marine ecosystems to global change. This approach, which blends theory with experimental data, provides new prospects for forecasting climate‐driven biodiversity change and its effects on ecosystem processes.
    Type: Article , PeerReviewed
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