ALBERT

Beschreibung: The accurate knowledge of the Earth’s orientation and rotation in space is essential for a broad variety of scientific and societal applications. Among others, these include global positioning, near-Earth and deep-space navigation, the realisation of precise reference and time systems as well as studies of geodynamics and global change phenomena. In this paper, we present a refined strategy for processing and combining Very Long Baseline Interferometry (VLBI), Satellite Laser Ranging (SLR), Global Navigation Satellite Systems (GNSS), and Doppler Orbitography and Radiopositioning Integrated by Satellite (DORIS) observations at the normal equation level and formulate recommendations for a consistent processing of the space-geodetic input data. Based on the developed strategy, we determine final and rapid Earth rotation parameter (ERP) solutions with low latency that also serve as the basis for a subsequent prediction of ERPs involving effective angular momentum data. Realising final ERPs on an accuracy level comparable to the final ERP benchmark solutions IERS 14C04 and JPL COMB2018, our strategy allows to enhance the consistency between final, rapid and predicted ERPs in terms of RMS differences by up to 50% compared to existing solutions. The findings of the study thus support the ambitious goals of the Global Geodetic Observing System (GGOS) in providing highly accurate and consistent time series of geodetic parameters for science and applications.

Beschreibung: BACKGROUND AND OBJECTIVES: Soil or rock types in a region are often interpreted qualitatively by visually comparing various geophysical properties such as seismic wave velocity and vulnerability, as well as gravity data. Better insight and less human-dependent interpretation of soil types can be obtained from a joint analysis of separated and independent geophysical parameters. This paper discusses the application of a neural network approach to derive rock properties and seismic vulnerability from horizontal-to-vertical seismic ratio and seismic wave velocity data recorded in Majalengka-West Java, Indonesia.METHODS: Seismic microtremors were recorded at 54 locations and additionally multichannel analyses of surface wave experiments were performed at 18 locations because the multichannel analyses of surface wave experiment needs more effort and space. From the two methods, the values of the average shear wave velocity for the upper 30 meters, peak amplitudes and the dominant frequency between the measurement points were obtained from the interpolation of those geophysical data. Neural network was then applied to adaptively cluster and map the geophysical parameters. Four learning model clusters were developed from the three input seismic parameters: shear wave velocity, peak amplitude, and dominant frequency. FINDINGS: Generally, the values of the horizontal to vertical spectral ratios in the west of the study area were low (less than 5) compared with those in the southeastern part. The dominant frequency values in the west were mostly low at around 0.1–3 Hertz, associated with thick sedimentary layer. The pattern of the shear wave velocity map correlates with that of the horizontal to vertical spectral ratio map as the amplification is related to the soil or rock rigidity represented by the shear wave velocity. The combination of the geophysical data showed new features which is not found on the geological map such as in the eastern part of the study area. CONCLUSION: The application of the neural network based clustering analysis to the geophysical data revealed four rock types which are difficult to observe visually. The four clusters classified based on the variation of the geophysical parameters show a good correlation to rock types obtained from previous geological surveys. The clustering classified safe and vulnerable regions although detailed investigation is still required for confirmation before further development. This study demonstrates that low-cost geophysical experiments combined with neural network-based clustering can provide additional information which is important for seismic hazard mitigation in densely populated areas.

Beschreibung: Tropical Lake Sentani in the Indonesian Province Papua consists of four separate basins and is surrounded by a catchment with a very diverse geology. We characterized the surface sediment (upper 5 cm) of the lake’s four sub-basins based on multivariate statistical analyses (principal component analysis, hierarchical clustering) of major element compositions obtained by X-ray fluorescence scanning. Three types of sediment are identified based on distinct compositional differences between rivers, shallow/proximal and deep/distal lake sediments. The different sediment types are mainly characterized by the correlation of elements associated with redox processes (S, Mn, Fe), carbonates (Ca), and detrital input (Ti, Al, Si, K) derived by river discharge. The relatively coarse-grained river sediments mainly derive form the mafic catchment geology and contribution of the limestone catchment geology is only limited. Correlation of redox sensitive and detrital elements are used to reveal oxidation conditions, and indicate oxic conditions in river samples and reducing conditions for lake sediments. Organic carbon (TOC) generally correlates with redox sensitive elements, although a correlation between TOC and individual elements change strongly between the three sediment types. Pyrite is the quantitatively dominant reduced sulfur mineral, monosulfides only reach appreciable concentrations in samples from rivers draining mafic and ultramafic catchments. Our study shows large spatial heterogeneity within the lake’s sub-basins that is mainly caused by catchment geology and topography, river runoff as well as the bathymetry and the depth of the oxycline. We show that knowledge about lateral heterogeneity is crucial for understanding the geochemical and sedimentological variations recorded by these sediments. The highly variable conditions make Lake Sentani a natural laboratory, with its different sub-basins representing different depositional environments under identical tropical climate conditions.

Beschreibung: Along the Northern Chilean active continental margin, the subducting Nazca plate is characterized by a rough sea floor topography that has been suggested to control the rupture behaviour of megathrust earthquakes. However, there is still debate of what structures exactly controlled the extent of the rupture of the Mw 8.12014 April 1st Iquique earthquake and why it only broke 1/3 of a large seismic gap that last ruptured completely in 1877. To better understand the seismotectonic segmentation of the northern Chilean convergent margin, we use datasets from different geophysical and geodetic studies in this area to produce a 3D model. We combine depth migrated images of the two northernmost multi-channel seismic reflection CINCA’95 (Crustal Investigations off- and onshore Nazca Plate/Central Andes) lines, bathymetry data, coseismic slip models, geodetic coupling, seismic b values, relocated seismic events and the morphology of the subduction interface from gravity modelling. The interface morphology shows a prominent surface relief that spacially correlates with the rupture process of the mainshock on April 1st and also for the largest aftershock on April 3rd. The main slip area exhibits a strong correlation with a large elongated topographic depression of the subducting slab. An elongated topographic high on the subducting plate to the south of that depression correlates with low pre-seismic locking and very likely acted as a barrier for rupture propagation for the main shock, as well as for the largest after shock. A subducted circular topographic high of 25 km in diameter located updip of the rupture area, possibly prevented coseismic slip to rupture all the way up to the trench axis. Thus, our observations support that subducting sea floor morphology plays an important role controlling rupture processes.

Beschreibung: Modern continental crust has evolved to a more potassic, granitic composition than early continental crust, which comprises largely sodic TTG-suite magmas. The present paradigm holds that the latter are largely “juvenile” (in the sense that the time from mantle extraction to felsic crust production is comparatively short, of the order 10–100 Ma) while the former represent recycled older crust of igneous or sedimentary composition. The data from high-Mg diorites, tonalites, granodiorites and potassic granites of the 125–115 Ma Menglian Batholith (SE Tibet) exemplify the modern situation and can therefore be used to constrain current crust formation processes. These rocks have higher concentrations of incompatible elements than magmatic rocks from typical continental arc settings, with a continuum of increasing K2O/Na2O ratios, SiO2, K2O, Rb, and Th concentrations juxtaposed with decreasing MgO, CaO, and Sr. They consistently record both higher zircon δ18O values than mantle values and decoupled Ndsingle bondHf isotope systems caused by the interaction of subducted sediments with the mantle wedge. Petrogenetic mechanisms that connect the suite include crystal fractionation within the diorites, melting of the lower crust induced by advection of heat and water by the diorites, and high-level fractionation of the tonalite-granodiorite suite to produce the high-silica granites. Therefore, this example of modern fertile continental crust had a five-stage evolution: (1) subduction-enrichment of the mantle source, (2) mantle melting to produce mafic magmas that pooled in or below the lower crust, (3) mafic magma differentiation to produce the tonalite-granodioritic magmas controlled by crystal-liquid equilibria, (4) crustal melting and admixture to the evolving felsic magmas and (5) final high-level fractionation and melt extraction to produce the silicic extreme, enriched in incompatible elements such as Rb, Th and K. This model could be a general mechanism for how modern mature continental crust evolves. Importantly, it indicates a significant role for mafic magmas and thence a more important role for juvenile additions than is generally accepted.

Beschreibung: Most tectonic models consider that the “Samail subduction zone” was the only subduction zone at the mid-Cretaceous convergent Arabian margin. We report four new Rb-Sr multimineral isochron ages from high-pressure (HP) rocks and a major shear zone of the uppermost Ruwi-Yiti Unit of the Saih Hatat window in the Oman Mountains of NE Arabia. These ages demand a reassessment of the intraoceanic suprasubduction-zone evolution that formed the Samail Ophiolite and its metamorphic sole in the Samail subduction zone. Our new ages constrain waning HP metamorphism of the Ruwi subunit at ∼99-96 Ma and associated deformation in the Yenkit shear zone between ∼104 and 93 Ma. Our ages for late stages of deformation and HP metamorphism (thermal gradients of ∼8–10°C km−1) overlap with published ages of ∼105-102 Ma for Samail-subduction-zone prograde-to-peak metamorphism (thermal gradients of ∼20–25°C km−1), subsequent decompressional partial melting of the metamorphic sole and suprasubduction-zone crystallization of the Samail Ophiolite (thermal gradients of ∼30°C km−1) between ∼100 and 93 Ma. Thermal considerations demand that two subduction zones existed at the mid-Cretaceous Arabian margin. High-pressure metamorphism of the Ruwi-Yiti rocks occurred in a mature, thermally equilibrated “Ruwi subduction zone” that formed at ∼110 Ma. Initiation of the infant, thermally unequilibrated and, thus, immature, outboard intraoceanic Samail subduction zone occurred at ∼105 Ma. The Samail Ophiolite and its metamorphic sole were then thrust over the exhuming Ruwi-Yiti HP rocks and onto the Arabian margin after ∼92 Ma, while the bulk of the Saih Hatat HP rocks below the Ruwi-Yiti Unit started to be underthrust in the Ruwi subduction zone.

Beschreibung: A massive landslide often causes long-lasting instability dynamics that need to be analyzed in detail for risk management and mitigation. Multiple satellite remote sensing observations, in-situ measurements, and geophysical approaches have been jointly implemented to monitor and interpret the life cycle of landslides and their failure mechanisms from various perspectives. In this work, we propose a framework where satellite optical and synthetic aperture radar (SAR) remote sensing techniques are combined with feature extractions using independent component analysis (ICA) and a mathematical relaxation model to assess the complete four-dimensional (4D) spatiotemporal patterns of post-failure slope evolution. The large, deep-seated Aniangzhai landslide in Southwest China that occurred on 17 June 2020 is comprehensively analyzed and characterized for its post-failure mechanism. Time series of Planet high-resolution optical images are first explored to derive the large horizontal motions for the first six months after the failure. Spatiotemporal dynamics of line-of-sight (LOS) displacement in the landslide body are then derived between November 2020 and February 2022 by combining 40 TerraSAR-X (TSX) High-resolution Spotlight (HS) images and 76 medium-resolution Sentinel-1 (S1) SAR datasets using Multi-temporal InSAR (MTI) method. The InSAR-derived results are subsequently analyzed with ICA to find common deformation components of points between optical and MTI results, indicating the same temporal evolution in the deformation pattern. Finally, the complete 4D deformation field for the whole post-failure period is modeled using a decaying exponential model representing stress relaxation after the failure by integrating multiple remote sensing datasets. Cross-correlation analysis of Planet imagery shows a decaying exponential pattern of post-failure displacements with an approximately 94% reduction in the deformation rate after six months with respect to the co-failure event. MTI analysis suggests a maximum LOS displacement rate of approximately 30 cm/year over the main failure body from November 2020 to February 2022; while the high-resolution TSX datasets show irreplaceable advantages in choosing the number of measurement points in MTI analysis with the number of measurement points being five times larger than those obtained by S1 datasets. The ICA analysis reveals three main types of kinematic patterns in the temporal evolution of post-failure deformation in MTI results, the dominant one being an exponential declining pattern similar to the results from Planet observations. Integrated 4D deformation modeling suggests that the most significant post-failure displacement mainly occurred toward the west, amounting to 28 m during the entire post-failure acquisitions from June 2020 until February 2022. Additionally, maximum displacements of 17 m and 19 m occurred in this period toward the north and downward, respectively.

Beschreibung: Planned decommissioning of coal-fired plants in Europe requires innovative technical and economic strategies to support coal regions on their path towards a climate-resilient future. The repurposing of open pit mines into hybrid pumped hydro power storage (HPHS) of excess energy from the electric grid, and renewable sources will contribute to the EU Green Deal, increase the economic value, stabilize the regional job market and contribute to the EU energy supply security. This study aims to present a preliminary phase of a geospatial workflow used to evaluate land suitability by implementing a multi-criteria decision making (MCDM) technique with an advanced geographic information system (GIS) in the context of an interdisciplinary feasibility study on HPHS in the Kardia lignite open pit mine (Western Macedonia, Greece). The introduced geospatial analysis is based on the utilization of the constraints and ranking criteria within the boundaries of the abandoned mine regarding specific topographic and proximity criteria. The applied criteria were selected from the literature, while for their weights, the experts’ judgement was introduced by implementing the analytic hierarchy process (AHP), in the framework of the ATLANTIS research program. According to the results, seven regions were recognized as suitable, with a potential energy storage capacity from 1.09 to 5.16 GWh. Particularly, the present study’s results reveal that 9.27% (212,884 m2) of the area had a very low suitability, 15.83% (363,599 m2) had a low suitability, 23.99% (550,998 m2) had a moderate suitability, 24.99% (573,813 m2) had a high suitability, and 25.92% (595,125 m2) had a very high suitability for the construction of the upper reservoir. The proposed semi-automatic geospatial workflow introduces an innovative tool that can be applied to open pit mines globally to identify the optimum design for an HPHS system depending on the existing lower reservoir.

Beschreibung: The minor and trace element composition of minerals provides critical insights into a variety of geological processes. Multi-element mapping by laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) is an important technique applied for this purpose and although the method is rapidly advancing, there remains a fundamental compromise between spatial resolution, detection limit, and experiment duration when using sequential mass analyzers. To address the limitation of limited analyte selection for high spatial resolution maps imposed by the sequential nature of typical quadrupole (Q)-ICP-MS, we tested the Aerosol Rapid Introduction System (ARIS) for repeat mapping of the same area. The ARIS is a high-speed transfer tubing system that reduces aerosol washout times, permitting resolution of individual pulses at 40–60 Hz. Here, the ARIS was tested not for pulse resolution but with novel operating conditions optimized to perform fast, high spatial resolution mapping of minor and trace element distribution in pyrite and marcasite. For this purpose, ablation was conducted with a 5 µm beam aperture, a repetition rate of 50 Hz, and a continuous stage scan speed of 40 µm s−1. For each LA-Q-ICP-MS map, data were acquired for six elements with an acquisition time of 20 ms per element. This deliberately reduced the individual pulse resolution of the ARIS but instead exploited the spatial resolution and sensitivity gains afforded by the high-laser repetition rate combined with efficient aerosol transfer. The new method successfully mapped trace elements at single to double-digit parts per million levels, and the maps reveal fine-scale zoning of trace elements with an effective x and y resolution of 5 µm, while white light interferometry showed that for each experiment, only ca. 1 µm of the sample was removed. Repeated mapping of the same area showed excellent correspondence not only between element concentrations in successive experiments but also in the shape, dimension, and location of regions of interest defined by concentration criteria. The very good repeatability of the elemental maps indicates that for studies requiring more analytes, successive mapping of additional elements is possible. By contrast with conventional very small spot (i.e., 5 µm) analysis, fast repetition rate and stage scan speed mapping avoids down-hole fractionation effects and minimizes accidental analysis of buried invisible inclusions. Compared to conventional LA-ICP-MS mapping, the method reduces the experiment time by 4–8 times.

Beschreibung: This paper presents a series of surface experimental simulations of methane-oriented underground coal gasification using hydrogen as gasification medium. The main aim of the experiments conducted was to evaluate the feasibility of methane-rich gas production through the in situ coal hydrogasification process. Two multi-day trials were carried out using large scale gasification facilities designed for ex situ experimental simulations of the underground coal gasification (UCG) process. Two different coals were investigated: the “Six Feet” semi-anthracite (Wales) and the “Wesoła" hard coal (Poland). The coal samples were extracted directly from the respective coal seams in the form of large blocks. The gasification tests were conducted in the artificial coal seams (0.41 × 0.41 × 3.05 m) under two distinct pressure regimes - 20 and 40 bar. The series of experiments conducted demonstrated that the physicochemical properties of coal (coal rank) considerably affect the hydrogasification process. For both gasification pressures applied, gas from “Six Feet” semi-anthracite was characterized by a higher content of methane. The average CH4 concentration for “Six Feet” experiment during the H2 stage was 24.12% at 20 bar and 27.03% at 40 bar. During the hydrogasification of “Wesoła" coal, CH4 concentration was 19.28% and 21.71% at 20 and 40 bar, respectively. The process was characterized by high stability and reproducibility of conditions favorable for methane formation in the whole sequence of gasification cycles. Although the feasibility of methane-rich gas production by underground hydrogasification was initially demonstrated, further techno-economic studies are necessary to assess the economic feasibility of methane production using this process.

Beschreibung: Forest soils have large contents of carbon (C) and total nitrogen (TN), which have significant spatial variability laterally across landscapes and vertically with depth due to decomposition, erosion and leaching. Therefore, the ratio of C to TN contents (C:N), a crucial indicator of soil quality and health, is also different depending on soil horizon. These attributes can cost-effectively and rapidly be estimated using visible–near infrared–shortwave infrared (VNIR–SWIR) spectroscopy. Nevertheless, the effect of different soil layers, particularly over large scales of highly heterogeneous forest soils, on the performance of the technique has rarely been attempted. This study evaluated the potential of VNIR–SWIR spectroscopy in quantification and variability analysis of C:N in soils from different organic and mineral layers of forested sites of the Czech Republic. At each site, we collected samples from the litter (L), fragmented (F) and humus (H) organic layers, and from the A1 (depth of 2–10 cm) and A2 (depth of 10–40 cm) mineral layers providing a total of 2505 samples. Support vector machine regression (SVMR) was used to train the prediction models of the selected attributes at each individual soil layer and the merged layer (profile). We further produced the spatial distribution maps of C:N as the target attribute at each soil layer. Results showed that the prediction accuracy based on the profile spectral data was adequate for all attributes. Moreover, F was the most accurately predicted layer, regardless of the soil attribute. C:N models and maps in the organic layers performed well although in mineral layers, models were poor and maps were reliable only in areas with low and moderate C:N. On the other hand, the study indicated that reflectance spectra could efficiently predict and map organic layers of the forested sites. Although, in mineral layers, high values of C:N (≥ 50) were not detectable in the map created based on the reflectance spectra. In general, the study suggests that VNIR–SWIR spectroscopy has the feasibility of modelling and mapping C:N in soil organic horizons based on national spectral data in the forests of the Czech Republic

Beschreibung: We present a study to estimate the large-scale landscape history of a continental margin, by establishing a source-to-sink volume balance between the eroding onshore areas and the offshore basins. Assuming erosion as the primary process for sediment production, we strive to constrain a numerical model of landscape evolution that balances the volumes of eroded materials from the continent and that deposited in the corresponding basins, with a ratio imposed for loss of erosion products. We use this approach to investigate the landscape history of Madagascar since the Late Cretaceous. The uplift history prescribed in the model is inferred from elevations of planation surfaces formed at various ages. By fitting the volumes of terrigenous sediments in the Morondava Basin along the west coast and the current elevation of the island, the landscape evolution model is optimized by constraining the erosion law parameters and ratios of sediment loss. The results include a best-fit landscape evolution model, which features two major periods of uplift and erosion during the Late Cretaceous and the middle to late Cenozoic. The model supports suggestions from previous studies that most of the high topography of the island was constructed since the middle to late Miocene, and on the central plateau the erosion has not reached an equilibrium with the high uplift rates in the late Cenozoic. Our models also indicate that over the geological time scale, a significant portion of materials eroded from Madagascar was not archived in the offshore basin, possibly consumed by chemical weathering, the intensity of which might have varied with climate.

Beschreibung: The interpretation of low-temperature thermochronology (LTT) data in magmatic and metallogenic provinces requires a knowledge of the geothermal field through time. There, the challenge is differentiating rapid cooling following transient perturbations of the geotherms (reheating) from exhumational cooling induced by erosion during tectonic uplift or normal faulting. The Takab Range Complex (NW Iran) is a basement-cored range of the Arabia-Eurasia collision zone that experienced voluminous Eocene to Miocene magmatism and mineralization. Our new apatite and zircon (U-Th-Sm)/He and apatite fission track data, together with field observations, a dedicated numerical thermal model, and a re-evaluation of available geochronology data document the occurrence of a complex geological and thermal history including: (a) late Cretaceous-Paleocene exhumation possibly controlled by regional contractional deformation followed by Eocene deposition; (b) Oligocene to possibly early Miocene (29 to 22–20 Ma) exhumation of basement rocks from 13 to 8 km of depth, most likely through normal faulting during a thermal anomaly that led to migmatization and partial melting; (c) early to late Miocene (∼22–20 or earlier to 11–10 Ma) regional subsidence with deposition of an up to ∼2- to 3-km-thick Oligo-Miocene sedimentary sequence in association with the emplacement of shallow intrusions, which led to a partial to total reset of our LTT systems sometime between 18 and 13 Ma; and (e) erosional exhumation after 11–10 Ma with the development of a transpressional system and a master, right-lateral, strike slip fault (Chahartagh Fault). Our data highlights the impact of magmatic reheating on LTT ages in areas affected by intense magmatism.

Beschreibung: To share best practices and to foster the research data management (RDM) community within Helmholtz, the Helmholtz Open Science Office hosted its first "Helmholtz Open Science Practice Forum Research Data Management" virtually in February 2022. A follow-up event on October 20, 2022 has taken up and continued this theme. The following aspects were highlighted through presentations with ample time for discussion in the forum: - Thinking and linking data, text, and research software together - Data Stewards, Data Librarians, Research Data Managers, Data Curators... – Their profiles and roles in Helmholtz - Data Management Plans – DMPs as Living Documents - Monitoring data publications

Beschreibung: Improving and homogenizing time and space reference systems on Earth and, more specifically, realizing the Terrestrial Reference Frame (TRF) with an accuracy of 1 mm and a long-term stability of 0.1 mm/year are relevant for many scientific and societal endeavors. The knowledge of the TRF is fundamental for Earth and navigation sciences. For instance, quantifying sea level change strongly depends on an accurate determination of the geocenter motion but also of the positions of continental and island reference stations, such as those located at tide gauges, as well as the ground stations of tracking networks. Also, numerous applications in geophysics require absolute millimeter precision from the reference frame, as for example monitoring tectonic motion or crustal deformation, contributing to a better understanding of natural hazards. The TRF accuracy to be achieved represents the consensus of various authorities, including the International Association of Geodesy (IAG), which has enunciated geodesy requirements for Earth sciences. Moreover, the United Nations Resolution 69/266 states that the full societal benefits in developing satellite missions for positioning and Remote Sensing of the Earth are realized only if they are referenced to a common global geodetic reference frame at the national, regional and global levels. Today we are still far from these ambitious accuracy and stability goals for the realization of the TRF. However, a combination and co-location of all four space geodetic techniques on one satellite platform can significantly contribute to achieving these goals. This is the purpose of the GENESIS mission, a component of the FutureNAV program of the European Space Agency. The GENESIS platform will be a dynamic space geodetic observatory carrying all the geodetic instruments referenced to one another through carefully calibrated space ties. The co-location of the techniques in space will solve the inconsistencies and biases between the different geodetic techniques in order to reach the TRF accuracy and stability goals endorsed by the various international authorities and the scientific community. The purpose of this paper is to review the state-of-the-art and explain the benefits of the GENESIS mission in Earth sciences, navigation sciences and metrology. This paper has been written and supported by a large community of scientists from many countries and working in several different fields of science, ranging from geophysics and geodesy to time and frequency metrology, navigation and positioning. As it is explained throughout this paper, there is a very high scientific consensus that the GENESIS mission would deliver exemplary science and societal benefits across a multidisciplinary range of Navigation and Earth sciences applications, constituting a global infrastructure that is internationally agreed to be strongly desirable.

Beschreibung: Our understanding of continental rifting is, in large parts, derived from the stratigraphic record. This record is, however, incomplete as it does not often capture the geomorphic and erosional signal of rifting. New 3D seismic reflection data reveals a Late Permian-Early Triassic landscape incised into the pre-rift basement of the northern North Sea. This landscape, which covers at least 542 km2, preserves a drainage system bound by two major tectonic faults. A quantitative geomorphic analysis of the drainage system reveals 68 catchments, with channel steepness and knickpoint analysis of catchment-hosted palaeo-rivers showing that the landscape preserved a 〉2 Myrs long period of transient tectonics. We interpret that this landscape records punctuated uplift of the footwall of a major rift-related normal fault (Vette Fault) at the onset of rifting. The landscape was preserved by a combination of relatively rapid subsidence in the hangingwall of a younger fault (Øygarden Fault) and burial by post-incision sediments. As such, we show how and why erosional landscapes are preserved in the stratigraphic record, and how they can help us understand the tectono-stratigraphic evolution of ancient continental rifts.

Beschreibung: Very Long Baseline Interferometry (VLBI) experiments are organized within the geodetic, astrometric and astronomical communities for different applications, requiring different observation strategies adopted in scheduling. Currently, the next- generation geodetic and astrometric VLBI Global Observing System (VGOS) is being established. Over the last years, evidence was presented that the delays introduced by the angular structure of the geodetic radio sources contribute significantly to the VGOS observable error budget. Consequently, correcting these structure delays through imaging will play an important part in the future, requiring a different scheduling approach. Within this work, a new source-centric VLBI scheduling approach is presented for improved imaging capabilities of geodetic observations. The algorithm is tested for a seven- and nine-station network and compared with classical geodetic schedules. Monte Carlo simulations are utilized to determine the expected geodetic and astrometric parameter precision, and two independent processing pipelines are used to assess the potential for astronomical source imaging. Based on the simulation results, it is revealed that with the new scheduling approach twice as many sources can be properly imaged. Furthermore, the precision of the Earth orientation parameter estimates is improved on average by 15%, while the source position coordinate estimates are on average improved by 50%. Tests with two VGOS networks of twelve and 29 antennas further reveal that the scheduling approach is also applicable to future VGOS networks.

Beschreibung: Biotite plays an important role in controlling Nb/Ta fractionation during subduction-related, dehydration reactions. It is probable that Nb–Ta-bearing minerals and Nb–Ta oxides could form from Nb–Ta-rich biotite as a result of fluid-aided alteration. However, the mechanism by how this alteration occurs is not well understood. In this study, a Nb-rich, Li-bearing biotite (up to 1232 ppm Nb) with REE-bearing inclusions (e.g., bastnäsite) is altered using pure H2O, as well as HCl-, NaOH-, NaF-, KF-, and MnF2-bearing solutions in a rapid-quench, cold-seal pressure vessel at 200 MPa, and 300 to 600 °C. A set of Nb-Ta-Ti alteration products (titanomagnetite, ilmenite, Nb-rutile, fergusonite, and aeschynite) formed successively over a series of temperatures, i.e., Nb-rutile + aeschynite formed first at 600 °C, followed by fergusonite + titanomagnetite ± ilmenite at 400 to 500 °C, and lastly titanomagnetite at 300 °C. The results from this study indicate that Nb–Ta-bearing oxides (titanomagnetite and ilmenite) and Nb–Ta oxides (Nb-rutile, fergusonite and aeschynite) can form via metasomatic reactions between Nb-rich, Li-bearing biotite and a variety of low pH, high pH, and F-bearing fluids. The formation of Nb-rutile with much higher Nb/Ta ratios (76.60) compared with Nb-rich, Li-bearing biotite (Nb/Ta: 24.79 in average), provides new insight into explaining the “missing high Nb/Ta reservoir”. Formation of Nb-rutile (Nb2O5: up to 31.71 wt%), fergusonite (Nb2O5: up to 42.62 wt%), and aeschynite (Nb2O5: up to 36.48 wt%) from Nb-bearing biotite indicates that metasomatic processes can lead to Nb mineralization in the form of oxides.

Beschreibung: Understanding the future fate of the Greenland Ice Sheet (GIS) in the context of anthropogenic CO2 emissions is crucial to predict sea level rise. With the fully coupled Earth system model of intermediate complexity CLIMBER-X, we study the stability of the GIS and its transient response to CO2 emissions over the next 10 Kyr. Bifurcation points exist at global temperature anomalies of 0.6 and 1.6 K relative to pre-industrial. For system states in the vicinity of the equilibrium ice volumes corresponding to these temperature anomalies, mass loss rate and sensitivity of mass loss to cumulative CO2 emission peak. These critical ice volumes are crossed for cumulative emissions of 1,000 and 2,500 GtC, which would cause long-term sea level rise by 1.8 and 6.9 m respectively. In summary, we find tipping of the GIS within the range of the temperature limits of the Paris agreement.

Beschreibung: Every year, millions of deaths are associated with the increased spread of antimicrobial resistance genes (ARGs) in bacteria. With the increasing urbanization of the global population, the spread of ARGs in urban bacteria has become a more severe threat to human health.

Beschreibung: Deliverable D2.3 reports the work performed in task 2.3 “Metal complexation and mineral precipitation” within the Reflect project. The task is divided into the subtasks 2.3.1 “Mineral solubility and precipitation kinetics”, 2.3.2 “Mineral precipitation by impedance spectroscopy” and 2.3.3 “Modelling mineral solubility”. A combination of experimental design, performed experiments and numerical modelling have increased the knowledge of mineral solubility and precipitation at high salinity condition in geothermal fluids.

Beschreibung: Naxos in the Greek Cyclades preserves a type example of polymetamorphism. The southern and northern parts of the island record different Tertiary P–T histories between Eocene and Miocene times, including a blueschist facies event, one or more amphibolite/greenschist facies overprint(s) and contact metamorphism. Age attributions for these events are inconsistent in the literature. Here, we propose a new approach that combines electron probe microanalyzer (EPMA) characterization of the white mica (WM) with 39Ar-40Ar–Rb-Sr multichronometry. Textural–petrographic–compositional observations reveal that the polygenetic WM consists of five different generations: pre-Eocene relicts, paragonite, high-Si phengite, low-Si phengite and muscovite. EPMA mapping of four WM samples, previously analysed by Rb-Sr, reveals major element compositions heterogeneous down to the μm scale. Each WM consists of chemically distinct generations, documenting submicron-scale retrogression of high-pressure (HP) phengite grains to muscovite. Four WM samples from a N-S traverse across the island were analysed by 39Ar-40Ar stepheating, comparing coarse and fine sieve size fractions to obtain overdetermined K-Ar systematics. Fine sieve fractions are richer in Cl than coarse ones. Linear arrays in Cl/K-age isotope correlation diagrams show two predominant WM generations (one Cl-poor at ca. 38 Ma and one Cl-rich at 〈20 Ma). A lower-grade sample from southern Naxos was less pervasively recrystallized, provides older ages and preserves at least three WM generations, including a relict WM with a pre-Palaeocene K-Ar age, consistent with the high Ar retentivity of WM in the absence of complete recrystallization. The age of the Cl-poor end-member WM approximates the age of the HP event, 38 Ma. Ar inheritance in Cretaceous mica relicts is heterogeneous at the single-grain scale. Comparing the degassing rates of the WM fractions rules out ‘multidomain’ diffusion. As no sample is monomineralic, the degassing rate of each polygenetic mica is instead controlled by the mass balanced sum of the unrelated rate constants of its constituent minerals. Given the commonness of zoned and composite micas, the approach detailed here is potentially useful for reconstructing polyphase metamorphic histories worldwide.

Beschreibung: Wetlands are the largest natural source of methane (CH4) to the atmosphere. The eddy covariance method provides robust measurements of net ecosystem exchange of CH4, but interpreting its spatiotemporal variations is challenging due to the co-occurrence of CH4 production, oxidation, and transport dynamics. Here, we estimate these three processes using a data-model fusion approach across 25 wetlands in temperate, boreal, and Arctic regions. Our data-constrained model—iPEACE—reasonably reproduced CH4 emissions at 19 of the 25 sites with normalized root mean square error of 0.59, correlation coefficient of 0.82, and normalized standard deviation of 0.87. Among the three processes, CH4 production appeared to be the most important process, followed by oxidation in explaining inter-site variations in CH4 emissions. Based on a sensitivity analysis, CH4 emissions were generally more sensitive to decreased water table than to increased gross primary productivity or soil temperature. For periods with leaf area index (LAI) of ≥20% of its annual peak, plant-mediated transport appeared to be the major pathway for CH4 transport. Contributions from ebullition and diffusion were relatively high during low LAI (〈20%) periods. The lag time between CH4 production and CH4 emissions tended to be short in fen sites (3 ± 2 days) and long in bog sites (13 ± 10 days). Based on a principal component analysis, we found that parameters for CH4 production, plant-mediated transport, and diffusion through water explained 77% of the variance in the parameters across the 19 sites, highlighting the importance of these parameters for predicting wetland CH4 emissions across biomes. These processes and associated parameters for CH4 emissions among and within the wetlands provide useful insights for interpreting observed net CH4 fluxes, estimating sensitivities to biophysical variables, and modeling global CH4 fluxes.

Beschreibung: The quality of groundwater resources in the Pra Basin (Ghana) is threatened by ongoing river pollution from illegal mining. To date, there are very limited data and literature on the hydrochemical characteristics of the basin. For the first time, we provide regional hydrochemical data on surface water and groundwater to gain insight into the geochemical processes and quality for drinking and irrigation purposes. We collected 90 samples from surface water (rivers) and groundwater (boreholes) and analysed them for their chemical parameters. We performed a water quality assessment using conventional water quality rating indices for drinking water and irrigation. Cluster and factor analysis were performed on the hydrochemical data to learn the chemical variations in the hydrochemical data. Bivariate ion plots were used to interpret the plausible geochemical processes controlling the composition of dissolved ions in surface water and groundwater. The water quality assessment using Water Quality Index (WQI) revealed that 74% of surface water and 20% of groundwater samples are of poor drinking quality and, therefore, cannot be used for drinking purposes. For irrigation, surface water and groundwater are of good quality based on Sodium Adsorption Ratio (SAR), Wilcox diagram and United States Salinity (USSL) indices. However, Mn and Fe (total) concentrations observed in most surface water samples are above the acceptable limit for irrigation and therefore require treatment to avoid soil acidification and loss of availability of vital soil nutrients. Manganese and iron (total) are identified as the main contaminants affecting the basin’s water quality. The hierarchical cluster analysis highlights the heterogeneity in the regional hydrochemical data, which showed three distinct spatial associations based on elevation differences. Groundwater composition chemically evolves from a Ca–HCO3 to a Na–HCO3 and finally to a Na–Cl water type along the flow regime from the recharge to the discharge zone. The bivariate ion plot and the factor analysis underscore silicate weathering, carbonate dissolution and ion exchange as the most likely geochemical processes driving the hydrochemical evolution of the Pra Basin groundwater. Going forward, geochemical models should be implemented to elucidate the dominant reaction pathways driving the evolution of groundwater chemistry in the Pra Basin.

Beschreibung: Carbonate rocks are highly reactive and can have higher ratios of chemical weathering to total denudation relative to most other rock types. Their chemical reactivity affects the first-order morphology of carbonate-dominated landscapes and their climate sensitivity to weathering. However, there have been few efforts to quantify the partitioning of denudation into mechanical erosion and chemical weathering in carbonate landscapes such that their sensitivity to changing climatic and tectonic conditions remains elusive. Here, we compile bedrock and catchment-averaged cosmogenic calcite–36Cl denudation rates and compare them to weathering rates derived from stream water chemistry from the same regions. Local bedrock denudation and weathering rates are comparable, ∼20–40 mm ka−1, whereas catchment-averaged denudation rates are ∼2.7 times higher. The discrepancy between bedrock and catchment-averaged denudation is 5 times lower compared to silicate-rich rocks, illustrating that elevated weathering rates make denudation more spatially uniform in carbonate-dominated landscapes. Catchment-averaged denudation rates correlate well with topographic relief and hillslope gradients, and moderate correlations with runoff can be explained by concurrent increases in weathering rates. Comparing denudation rates with weathering rates shows that mechanical erosion processes contribute ∼50 % of denudation in southern France and ∼70 % in Greece and Israel. Our results indicate that the partitioning between largely slope-independent chemical weathering and slope-dependent mechanical erosion varies based on climate and tectonics and impacts the landscape morphology. This leads us to propose a conceptual model whereby in humid, slowly uplifting regions, carbonates are associated with low-lying, flat topography because slope-independent chemical weathering dominates denudation. In contrast, in arid climates with rapid rock uplift rates, carbonate rocks form steep mountains that facilitate rapid, slope-dependent mechanical erosion required to compensate for inefficient chemical weathering and runoff loss to groundwater systems. This result suggests that carbonates represent an end member for interactions between climate, tectonics, and lithology.

Beschreibung: Marine heatwaves (MHWs) are prolonged extreme oceanic warm water events, that can cause substantial and sometimes devastating impacts on marine ecosystems. Our knowledge of regional and remote drivers, teleconnections, and local-scale processes underpinning large-scale and iconic MHWs has improved significantly over the past decade because of focused research efforts around the world. Dynamical knowledge of MHW drivers, including those from remote sources such as modes of climate variability and their teleconnections, coupled with local MHW amplification or decay processes, is critical to the process-based understanding of MHW predictability. However, the key development needed for effective adaptation and mitigation efforts by marine conservation and fisheries managers is better MHW prediction skill. MHW predictability depends on multiple factors including how we define MHWs, the regions in which they occur – e.g., coastal versus offshore, western boundary versus eastern boundary regions –, the spatial and temporal scales of the events, atmospheric heat flux versus ocean advection-driven events, and driver persistence. This presentation will explore MHW predictability on various timescales, focusing on the physical processes that offer a prediction. Some significant MHW events around Australia will be central to this discussion.

Beschreibung: It is possible to measure ocean wave data by drifting buoys even at far locations from the land and in the presence of strong currents such as the western boundary current. The author assessed how much the discrepancy between ERA5 wave data and drifting buoy wave data depended on the surface current speeds evaluated from the locations of the drifting buoys. The difference between ERA5 wave height and buoy wave height increases with increasing surface current speed. When the current is in the opposite direction from the mean wave direction, the ERA5 wave height is noticeably underestimated, and when the current is in the opposite direction from the mean wave direction, the wave height is overestimated. The maximum difference was about 20%. In the case of opposing and following currents, the wave periods from the ERA5 data and the drifting buoy also differ, mostly because of the Doppler shift.

Beschreibung: Northeast Japan is one of the world's most active subduction zones, having great earthquakes and volcanic eruptions, such as the M9.1 Tohoku Earthquake in 2011. Efforts to understand the subsurface structure via magnetotelluric studies have been extensive because electrical resistivity is sensitive to fluids in the crust and upper mantle. As a result, the deep, regional resistivity structure has been obtained beneath the northern and central parts of Northeast Japan (Ogawa et al., 1986; Ichiki et al., 2015). In this study, we aimed to image the southern part. This area has quaternary volcanoes on the backbone range and the back-arc side, active deformation regions, and shallow to deep seismic activities. Such activities are generally viewed to be caused by fluids in the crust and upper mantle that originated from the subducting slab (e.g., Iwamori, 1998; Wallace, 2005). So, we performed a wide-band magnetotelluric study by deploying electromagnetic field recording stations on three parallel NW-SE profile lines across the island arc. Each line consists of about 15 stations with nearly 10 km intervals. We estimated the MT impedance, vertical magnetic field transfer function (VMTF), and inter-station horizontal magnetic field transfer function (HMTF) at periods 0.03 - 13,000 seconds using the BIRRP code (Chave and Thomson, 2004). FEMTIC inversion code (Usui, 2015; Usui et al., 2017) was used for three-dimensional inversion because it can jointly invert the three response functions. In the presentation, we discuss the resulting resistivity structure and its correlation with active volcanoes and seismic activities.

Beschreibung: The mid-latitude ocean front has a considerable impact on the local climate and that the representation of the atmospheric structure was well reproduced for simulations using finer SST resolutions with models driven by SST with different resolutions. Although the mid-latitude oceanic front would play a role in improving the accuracy of seasonal forecasts, the impact on forecast accuracy is still poorly understood. Thus, in this study, we investigate the influence of the mid-latitude oceanic front on forecasting using the latest seasonal forecasting system of the Japan Meteorological Agency. Here, we focus on intra-seasonal predictions (mainly 3-4th week predictions) in the North Atlantic region in winter, by comparing hindcast experiments with different ocean model resolutions in 30 years of 1991-2020. It is found that the low-resolution model shows SST cooling south of the mid-latitude oceanic front and the weakening of local lower tropospheric circulation in response to the SST, consistent with previous studies. The accuracy of the predicted SST is high for the low-resolution model at the 100-km order scale, whereas the high-resolution model is more accurate for the region-averaged SST at the 1000-km scale. This accuracy deterioration for the finer scales is probably caused by the phase shift of oceanic eddies. There are high correlations of variabilities between the mid-latitude oceanic frontal region-wide averaged SST (40-75W, 35-45N) and atmospheric variables near the frontal zone. We also confirm that their ACCs are improved by about 0.1-0.2.

Beschreibung: Heat waves with higher frequencies and longer durations are spreading across the world, posing higher human health risks such as heatstroke, especially for outdoor pedestrians and workers. Particularly in subtropical and tropical cities, the concurrence of high temperature and high humidity can be deadly. In this study, we developed a street-level human thermal stress prediction system in Hong Kong, a subtropical megacity, by embedding a human heat balance model named HEATS into a mesoscale Weather Research and Forecasting (WRF) model with fine-resolution land utilization datasets from world urban database (WUDAPT) and Planning Department of Hong Kong SAR, China. First, the spatiotemporal patterns of air temperature and humidity during a typical heat wave period were simulated and validated against observations over the whole city, with mechanisms explained from different characteristics of local climate zones, anthropogenic emissions, sea-land breeze, and mountain barrier effect. Then hotspots of extreme heat stress along different streets in the most densely populated region of the city were evaluated during heatwave periods, which show different patterns compared to normal periods. In particular, the extra heat risk of older adults and the additional heat stress due to mask wearing were also examined over Hong Kong, where 95% people wearing facemasks outdoor during the COVID-19 pandemics since 2020, among which 20% of the population are aged over 65 or above. Our results can provide significant references for public health and urban planning to foster the development of a walkable, pedestrian-friendly, and healthy city.

Beschreibung: In the southern Chile subduction zone, the Nazca plate is subducting beneath the South American plate. This region was recently struck by great megathrust earthquakes and is characterized by the existence of a volcanic chain. In this study, we calculated the three-dimensional thermal structure in the southern Chile subduction zone associated with the subduction of the Nazca plate by using numerical simulations. Based on the obtained temperature distribution, we determined the temperature ranges for the coseismic slips of the two megathrust earthquakes and temperatures at the hypocentres of the interplate earthquakes. In addition, the distributions of the water content and dehydration gradient were calculated by using the phase diagrams and were compared with the location of the volcanic chain. As a result, we found that coseismic slips occurred only at temperatures lower than the 350 °C isotherm. This finding occurs because the effective friction coefficient increases as the slip velocity increases at the plate boundary where the temperature is higher than 350 °C. In addition, the hydrous minerals in and above the slab release fluids through dehydration reactions, which decrease the melting point of the mantle wedge, contributing to the formation of the volcanic chain.

Beschreibung: The 2011 Tohoku-Oki earthquake with M 9 occurred on March, 11, 2011. Many remarkable changes of crustal activity were observed in Japan after the earthquake. The Iwaki area, northeastern Japan, is one of the places that the seismic activity increased drastically. The high seismic activity area is located in a triangle area with one side length of about 50 km. The two boundaries at the depth of around 30 km and 15-23 km were detected in this area by the analysis of waveforms (Usuda et al., 2022). The two boundaries were identified as Moho and mid-crustal boundaries. It was suggested that the mid-crustal boundary was related to crustal fluid. The relationship between the time sequence of the seismicity (data of Japan Meteorological Agency) and the reflector of the mid-crustal boundary (Usuda et al., 2022) is researched in this study. The mid-crustal boundary dips northeast direction. The seismic activity began at just above the mid-crustal reflector at the southern part of the reflector. The seismicity spread to wide area on and around the mid-crustal reflector. The seismicity gap was found at the central part of the area. The large intraplate earthquake, 2011 Hamadoori earthquake (Mw 6.6), occurred on April 11, 2011 at the seismicity gap. The active seismicity area formed large triangle area. In Japan, it has been suggested that the source of large earthquake is related to crustal fluid. It is considered that the crustal earthquakes in Iwaki area are also related to the crustal fluid.

Beschreibung: Iceberg calving is a key process of mass loss at lake-calving glaciers, but there is uncertainty about implementing this process into glacier evolution models. An eight-year timeseries of images from a fixed camera near the terminus of Haupapa/Tasman Glacier is used to derive timeseries of (a) terminus position, (b) ice velocity, (c) height of the terminal ice cliff, and (d) height above flotation. Our results show that the terminus retreated 968 ± 5 m between 2013 and 2021. Ice velocity at the moving terminus averaged 43 ± 2 m/a. Seven large calving events (each greater than 10〈sup〉6〈/sup〉 m〈sup〉3〈/sup〉) accounted for 46% of the retreat of the glacier, while the rest resulted from sub-aerial calving and terminus melt. Buoyancy-driven calving events are associated with terminus uplift of up to 5.2 m over 2-3 days before calving, but the timing of calving is not related to the height of the terminal ice cliff. Repeat bathymetry shows that a sub-aqueous ice-ramp intermittently forms in front of the terminus, increasing the buoyancy of the terminus. We hypothesise that a small height above flotation is a necessary, but not sufficient, condition for calving. Another factor, i.e. an ice ramp or basal crevassing, is needed to initiate calving. The height above flotation stays within a narrow range (0-9%), which is used as a terminus boundary condition for a glacier evolution model to examine how sensitive the future state of the glacier is to details of the terminus boundary condition, and its parameters.

Beschreibung: Mirror modes are a universal plasma process, which has been observed across diverse plasma environments such as planetary magnetospheres, comets, and the solar wind. Their growth is due to free energy from anisotropies in the pressure and they play a pivotal role in constraining the plasma to marginal stability. In this study, Solar Orbiter was used to analyze trains of mirror mode structures in the solar wind and inside solar wind structures across heliocentric distances between 0.5-1 AU. These types of mirror modes are called mirror mode storms and differ from the more isolated, higher amplitude, and larger-scale structures that are more typically observed in these regions. We have investigated several fundamental properties of mirror mode storms: their dependence on heliospheric distance, association with local plasma properties, temporal/spatial scale, amplitude, and connections with larger-scale solar wind transients such as CMEs and SIRs. The main findings are that mirror mode storms can approach local ion scales and deviate from the typically assumed long-wavelength limit. They are frequently observed close to current sheets and on occasion found downstream of interplanetary shocks. The relative occurrence of these events is low and appeared to be observed during moderate-slow solar wind speeds.

Beschreibung: Convectively coupled equatorial Rossby waves (CCERWs) are an intrinsic part of the spectrum of tropical weather systems, and can bring extreme precipitation to tropical locations. They are usually interpreted as modified versions of the theoretical dry equatorial Rossby wave solutions of the shallow water equations. However, the structure and dynamics of CCERWs are rather different to their theoretical cousins. Here, a vorticity budget is presented for both theoretical equatorial Rossby waves and for CCERWs (based on reanalysis data). The different strengths of the vorticity budget terms between the theoretical waves and CCERWs gives insights into CCERW propagation and growth mechanisms, and provides a focus and testbed for future model and forecast improvements.

Beschreibung: Electromagnetic ion cyclotron (EMIC) emissions in the Earth’s inner magnetosphere are a significant driver of relativistic electron precipitation into the atmosphere. The amplitudes of EMIC waves often exceed 1 nT, introducing nonlinear effects not included in the diffusive quasi-linear theory. While the nonlinear effects have been previously studied analytically and by test-particle simulations, most studies focus on parallel-propagating monochromatic waves. Here we present results from test-particle simulations of relativistic electrons interacting with EMIC waves of different amplitudes and wave normal angles. Diffusive and advective components of pitch-angle scattering are analyzed, highlighting the important effect of harmonic resonances on both co-streaming and counter-streaming electrons. Backward-in-time simulations are used to obtain the perturbed phase space density distribution and study the loss-cone electron population. It is demonstrated that the net effect of advective and diffusive motion during one quarter-bounce results in near isotropization of the distribution unless the nonlinear phase-trapping effects become dominant. It is further revealed that particles below the fundamental resonance energy experience not only nonresonant scattering caused by the amplitude modulations but also fractional-resonant scattering stemming from nonlinearly perturbed trajectories. Finally, the simple monochromatic wave model with constant obliquity is replaced with a full-wave model based on finite-difference time-domain simulations initialized with waveforms from spacecraft measurements. Differences between the two models are discussed, assessing the limitations of monochromatic models in the analysis of relativistic electron scattering and precipitation.

Beschreibung: Hydrometeorological impacts, like floods, heat waves or droughts, affect many aspects of daily life and economic sectors in Central Europe such as health, water supply, agriculture, hydropower or transport. Within the last decade, the transport along the major European waterways heavily suffered from multiple droughts leading to remarkable low flow events resulting in disruptions in industrial production, limitations in fuel supply and significant economic losses. Future climate change is expected to lead to prolonged, more intense and more frequent low flow situations.In this context, the Federal Institute of Hydrology (BfG) developed and implemented multiple operational services providing hydrological information for the waterways in Germany on different time-scales: (1) An observation-based nationwide low flow information system is being developed, which will merge the multitude of information in order to facilitate a consistent evaluation and classification of low flow situations. (2) The well-established short-range water level forecasts are complemented by probabilistic medium-range to sub-seasonal forecasts for relevant gauges. Flow and water-level forecasts up to 6 weeks ahead are already operational (https://www.elwis.de/), forecasts on seasonal and decadal time scales are subject of current research. (3) On the multidecadal- to centennial time scale, BfG provides projections of future river flow, water levels, water temperatures and further ecological parameters. This service is part of a national “core service climate and water" supporting the German adaptation strategy since 2020 (https://ws-klimaportal.bafg.de/). The combination of these services supports operational and strategical decision making and contributes to an increased resilience of waterway transport with regards to hydrological hazards.

Beschreibung: 〉New results on Southern Ocean heat exchange and wind forcing are presented with a focus on zonal asymmetry between surface ocean heat gain in the Atlantic/Indian sector and heat loss in the Pacific sector. The asymmetry arises from an intersector variation in the humidity gradient between the sea surface and near surface atmosphere. This gradient increases by 60% in the Pacific sector enabling a 20 Wm〈sup〉-2〈/sup〉 stronger latent heat loss compared to the Atlantic/Indian sector. A new zonal asymmetry metric is used for intercomparison of atmospheric reanalyses and CMIP6 climate simulations. CMIP6 has weaker Atlantic/Indian sector heat gain compared to the reanalyses primarily due to Indian Ocean sector differences. The potential for surface flux buoys to provide an observation-based counterpart to the asymmetry metric is explored. Over the past decade, flux buoys have been deployed at two sites (south of Tasmania and upstream of Drake Passage). The data record provided by these moorings is assessed and an argument developed for a third buoy to sample the Atlantic/Indian sector of the asymmetry metric. In addition, we assess evidence that the main westerly wind belt has strengthened and moved southward in recent decades using the ERA5 reanalysis. We find only marginal evidence of a southward broadening of the belt in the Atlantic /Indian sector and northward broadening in the Pacific sector and that the latitude of maximum wind speed remains essentially unchanged.

Beschreibung: While 12 years have already passed since the 2011 Tohoku-oki earthquake (M9.0), postseismic deformation of the earthquake is still ongoing. In order to detect the postseismic deformation of the Tohoku-oki earthquake, we have been performing repeating observations at seafloor sites for the GNSS-Acoustic (GNSS-A) geodetic observation technique since 2012 using both manned research vessels and an unmanned surface vehicle, called Wave Glider (WG), as a sea surface platform. We developed and tested a system to conduct the GNSS-A observations using the WG in 2019 and have continuously operated the system twice a year since 2020, visiting many (around 15) observation sites. Based on the observation data collected using research vessels and the WG, we estimated the displacement time series of the seafloor transponder array of each site. The spatio-temporal variations in seafloor crustal deformation after the 2011 Tohoku-oki earthquake indicate that the viscoelastic relaxation is the primary cause of the westward motion around the main rupture area of the M9 event, while the afterslip on the shallow plate interface played an important role in producing eastward displacements in the region south to the main rupture area. With respect to the region north to the main rupture area, no distinct spatial deformation pattern has been observed. This implies that multiple factors, i.e., viscoelastic relaxation, afterslip, interplate locking, and episodic slow slip events, are responsible for the complicated spatial deformation in this region. We will also report the current conditions of the equipment for GNSS-A observations in the presentation.

Beschreibung: 〉Glaciers in West Antarctica are accelerating extremely rapidly and discharging enormous quantities of ice into the ocean, adding to global sea level. However, while ice loss factors in this region are important to consider, the other side of the mass balance equation – accumulation - also has a strong bearing on overall ice mass. In this study, we examine extreme accumulation events over the West Antarctic region focusing on the Thwaites and Pine Island glaciers. Several regional climate models (MetUM, HCLIM and Polar-WRF) are used to dynamically downscale ERA5 reanalysis to 12 km, 3 km and 1 km resolution and we compare against AMIGOS snow accumulation data to validate and add value to the model simulations. In this work we will explore the characteristics of extreme precipitation events and evaluate how enhanced resolution impacts the quality of simulations.

Beschreibung: With the strong rise of the current solar cycle 25 also the number of solar eruptions, like solar flares and coronal mass ejections (CMEs), increases. These solar events have the capability to trigger geomagnetic storms, which may disrupt and damage satellites in space as well as technical infrastructure on Earth. The forecasting tool SODA (Satellite Orbit DecAy) is based on an interdisciplinary analysis of geodetic observations and solar wind in-situ measurements, and was developed in cooperation between the University of Graz and the Graz University of Technology. It allows the prediction of the impact of CME events on the altitude of low Earth orbiting satellites with a lead time of 15 hours. To calculate the storm induced orbit decay we analyzed 299 CME events over a period of 15 years. Appropriated variations in the thermospheric neutral mass density, were derived from measurements of the CHAMP, GRACE and SWARM satellite missions. In addition we investigated deviations in the magnetic field component Bz measured by the ACE and the DSCOVR spacecraft at the L1 point. The analysis of the CME induced orbit decays and the interplanetary magnetic field showed a strong correlation as well as a time delay between the CME and the associated thermospheric response. This correlation is implemented in the real time forecasting tool SODA, which is implemented in the ESA Space Safety Program (Ionospheric Weather Expert Service Center).

Beschreibung: Lentic small water bodies (LSWB) are widespread globally. They fulfill a variety of ecohydrological tasks and are of central importance for biodiversity in rural areas. Due to their size and location, they interact with their environment in complex ways not found in other types of water bodies. Plant protection products (PPP) and their transformation products (TP) pose a particular risk to them. However, the database of their contamination is low and inhomogeneous and transport pathways have not been sufficiently investigated so far. This study focuses on two LSWB in northern Germany that were monitored for their PSM/TP contamination and hydrological connectivity in a high-resolution measurement campaign from 10/1/20 to 10/31/21. Surface runoff, lateral flow, groundwater, drainage water, and surface water of the LSWB were analyzed for 26 PPP/TP. Based on recorded hydrological data and tracer experiments, water balances were established. Results show multiple findings of up to eight PPP/TP in all samples. In addition, several input and output pathways as well as different temporal dynamics of the various PPP/TP concentrations were identified. A pronounced interaction between the LSWB and the shallow groundwater enabling a PPP/TP exchange was observed. LSWB and shallow groundwater showed a constant and high load of the non-applied TP metazachlor-ESA. Metazachlor-ESA was measured with the highest concentrations of up to 11.66 µg L〈sup〉-1〈/sup〉 in the shallow groundwater and loads of up to 3.12 g in a single inflow per month. For one of the LSWB, a drainage system was a major input pathway for PPP/TP.

Beschreibung: We revisit observed zonal wind trends using 40 years of satellite-era reanalysis products and find evidence that general poleward shifts are emerging, often with low significance but notable similarity across different seasons and hemispheres. While much recent work has focused on the jet response to amplified Arctic warming, the observed trends are more consistent with the known sensitivity of the circulation to tropical warming. The circulation trends are within the range of historical model simulations but are relatively large compared to the models when the accompanying trends in upper tropospheric temperature gradients are considered. The balance between tropical warming and jet shifts should therefore be closely monitored in the near future. We also present a new hypothesis concerning the sensitivity of the circulation response to tropical heating which may be one factor affecting this balance.

Beschreibung: Sea-level rise, changes in storminess and population growth are increasing the risks of coastal flooding. The impacts are amplified in coastal cities due to the high concentration of inhabitants, infrastructure and services. Storm surge barriers can provide flood protection in these low-lying areas with long exposed coastlines. Maintenance is vital to ensure these complex and unique structures remain reliable and comply with legal protection standards. To ensure safe working conditions, water level thresholds above which maintenance work must stop are defined. This study evaluates the changes in past and future water levels exceeding the maintenance threshold to inform management, maintenance and operation strategies of storm surge barriers. The Maeslant barrier in the Netherlands is used as a case study. Results show that 13% of maintenance threshold exceedances occurred during the maintenance season. The effect of sea-level rise and natural inter-annual tidal cycles on future threshold exceedances is also assessed. Findings reveal that the maintenance window will shift earlier in the year and narrow until exceedances occur regularly all year-round. As sea-levels rise, tides play an increasingly dominant role in maintenance threshold exceedances, which in turn will significantly influence maintenance work. This analysis highlights that maintenance strategies at the Maeslant barrier need to be adapted for the barrier to remain operational until its design life of 2100. This analysis can be applied to other existing barriers to assess future intervention points and for barriers in the design phase to verify the implications of design decisions on planned maintenance

Beschreibung: The abyssal ocean circulation is a key component of the global meridional overturning circulation, cycling heat, carbon, oxygen and nutrients throughout the world ocean. The strongest historical trend observed in the abyssal ocean is warming at high southern latitudes, yet it is unclear what processes have driven this warming, and whether it is linked to a slowdown in the ocean's overturning circulation. Furthermore, future change in the abyssal overturning remains uncertain, with the latest CMIP6 projections not accounting for dynamic ice-sheet melt. In this talk I will present new transient forced high-resolution coupled ocean – sea-ice model simulations to show that under a high emissions scenario, abyssal warming is set to accelerate over the next 30 years. We find that meltwater input around Antarctica drives a contraction of Antarctic Bottom Water (AABW), opening a pathway that allows warm Circumpolar Deep Water greater access to the continental shelf. The reduction in AABW formation results in warming and ageing of the abyssal ocean, consistent with recent measurements. In contrast, projected wind and thermal forcing has little impact on the properties, age, and volume of AABW. These results highlight the critical importance of Antarctic meltwater in setting the abyssal ocean overturning, with implications for global ocean biogeochemistry and climate that could last for centuries.

Beschreibung: Heat waves are among the deadliest climate hazards. Yet the relative importance of the physical processes causing their near-surface temperature anomalies (′)—advection of air from climatologically warmer regions, adiabatic warming in subsiding air and diabatic heating—is still a matter of debate. Here we quantify the importance of these processes by evaluating the ′ budget along air-parcel backward trajectories. We first show that the extreme near-surface ′ during the June 2021 heat wave in western North America was produced primarily by diabatic heating and, to a smaller extent, by adiabatic warming. Systematically decomposing ′ during the hottest days of each year (TX1day events) in 1979–2020 globally, we find strong geographical variations with a dominance of advection over mid-latitude oceans, adiabatic warming near mountain ranges and diabatic heating over tropical and subtropical land masses. In many regions, however, TX1day events arise from a combination of these processes. In the global mean, TX1day anomalies form along trajectories over roughly 60 h and 1,000 km, although with large regional variability. This study thus reveals inherently non-local and regionally distinct formation pathways of hot extremes, quantifies the crucial factors determining their magnitude and enables new quantitative ways of climate model evaluation regarding hot extremes.

Beschreibung: The Sun has an obvious quasi-11-year cycle and numerous short-term eruptive activities. From the aspect of energy, there are four processes of energy transmission in the effectuation chain of solar forcing to the climate system: the solar energy input to the atmosphere, the atmospheric absorption to the input energy, the transformation of the absorbed energy to dynamic and thermodynamic responses in the atmosphere, and the coupling among all the layers affected by solar forcings. However, the four processes have not been discussed in their entirety. In this present paper, studies in recent decade on how the solar radiation varies during the solar cycle as well as the eruptions, and correspondingly how the terrestrial atmosphere absorbs the input solar energy are reviewed.

Beschreibung: Hybrid simulations of tail dynamics created with the Auburn Global Hybrid Code in 3-D (ANGIE3D) suggest that tail flows caused by reconnection events are closely related to the dynamics of Alfvén waves propagating from the magnetotail to the ionosphere. To understand the dynamical coupling process described by the simulations, we consider a simulated time series of plasma sheet structures associated with tail flows. As these structures drift inward, they appear to cause responses in the Poynting flux into the ionosphere. We utilize transfer entropy to identify causal, non-linear relationships between the tail flows and the Poynting flux into the ionosphere. We present 2-D and 3-D plots showing these relationships over time and the locations at which they occur. Results suggest that flows in the plasma sheet are the primary driver of the Poynting flux, which is consistent with expectations. They also illustrate the behaviors and relative locations of simulated structures on small and large timescales. This work demonstrates how system science tools such as transfer entropy can be used in conjunction with complex simulations to describe the underlying system dynamics and provide a framework for understanding the interrelated components, functions, and causalities in the system.

Beschreibung: 〉While near-freezing precipitation events have large impacts on human and natural systems, fundamental challenges remain in our ability to adequately observe, diagnose, simulate, and predict these events. The Winter Precipitation Type Research Multiscale Experiment (WINTRE-MIX) was designed to study the multiscale processes influencing the variability and predictability of p-type (rain, drizzle, freezing rain, freezing drizzle, wet snow, ice pellets, and snow) as well as the precipitation accumulation under near-freezing surface conditions. The experiment was conducted in February-March 2022 in the vicinity of Montreal. The field campaign utilized operational networks (New York State Mesonet, Canada Foundation of Innovation Climate Sentinels) and research instruments like the NRC Convair-580 research aircraft with a suite of in-situ and remote sensors, one C-band on Wheels (COW), two X-band Doppler on Wheels (DOWs) radars, mobile sounding systems, and manual p-type observation stations. We will analyze the variability of mesoscale cloud and precipitation structures and mesoscale flow during near-freezing surface conditions. Small-scale vertical motions within clouds (convective generating cells, coherent wave motions, and shear-driven turbulence) are shown to enhance the formation of ice in supercooled clouds, leading to the enhancement of surface snow or rain. Mesoscale precipitation bands, produced by either convergence of mesoscale terrain-channeled flows or by embedded disturbances within synoptic storms, locally enhance vertical motion, increase cloud depth, and intensify precipitation rates.

Beschreibung: 〉The Atlantic meridional overturning circulation (AMOC) is crucial in regulating the global climate, and understanding its potential changes under climate change is important. There is growing concern about the impact of natural processes, such as Antarctic meltwater discharge, that are not accounted for in current climate models on a global scale. In this study, we hence carried out idealized experiments to investigate the AMOC's response to Antarctic meltwater input, finding a non-monotonic response of AMOC. The meltwater-instigated cold SST propagates globally, ultimately strengthening the AMOC through enhanced convection in the subpolar northern Atlantic. However, in the early stages, a tropical SST pattern excites an atmospheric teleconnection, weakening the convection, and resulting in even weaker AMOC. This non-monotonic impact highlights the importance of the atmosphere in pole-to-pole interactions and raises the possibility of abrupt climate change in the future.

Beschreibung: On January 2023, NASA's Parker Solar Probe (PSP) mission had completed 14 of its scheduled 24 orbits around the Sun, with the closest approach (i.e., perihelion) of 13.28 solar radii from the Sun's center. PSP's primary science goal is to determine the structure and dynamics of the Sun's coronal magnetic field, understand how the solar corona and wind are heated and accelerated, and determine what processes accelerate energetic particles. The science data returned by PSP led to significant discoveries and potential breakthroughs, yielding more than 700 peer-reviewed publications. The first four years of the prime mission were mainly during the solar cycle minimum. With the rise of solar activity, PSP will explore solar wind variability as the cycle progress to its maximum. I will present an overview of the major scientific discoveries by PSP and the mission's outlook.

Beschreibung: 〉The improvement of GRACE-FO monthly gravity field models requires, on the one hand, updated observation data and background force models, and on the other hand refined data processing strategies. In this contribution, we investigate the impact of different accelerometer and orbit data processing strategies on the quality of gravity field models recovered from GRACE-FO L1B data using the classical dynamic approach. For accelerometer modeling, various calibration parameterizations and different transplant products, i.e., those produced by JPL (ACT and ACH) and TU Graz, are compared. Our results indicate that heavy parameterizations, e.g., daily scale parameters, tend to have unfavorable effects on gravity field solutions, especially for resonant spherical harmonics, which can be attributed to the fact that the GRACE-D accelerometer uses transplanted instead of real data. For orbit modeling, the issues of spectral sensitivities, sampling rates, optimal weights, and stochastic modeling are systematically discussed in terms of both numerical simulations and real data cases, which tries to address the long-standing concern, that is, how to optimally use orbit data in GRACE/GRACE-FO gravity field recovery.

Beschreibung: The North China Craton (NCC) is one of the oldest craton in the world. Since the Cenozoic, the NCC has experienced strong lithospheric thinning, accompanied by extensive tectonic deformation and volcanic activities. To better constrain the geodynamic processes and mechanisms of the lithospheric deformation, we used a linear damped least squares method to inverse simultaneously Rayleigh wave phase velocity and azimuthal anisotropy at periods of 10-80 s with teleseismic data recorded by 388 permanent stations in the NCC and its adjacent areas. The results reveal that the anomalies of Rayleigh wave phase velocity and azimuthal anisotropy are in good agreement with the tectonic domains in the NCC. The whole lithosphere of the Ordos block shows a high-phase velocity and rotated fast axis, which is related to the well-preserved thick lithospheric root and counterclockwise rotation of the Ordos block. The horizontal extension of the upwelling materials within the lower crust under the Datong volcano contributes to the regional rotation pattern of the fast axis direction of Rayleigh wave together with a distinct low-velocity anomaly. A NW-SE trending azimuthal anisotropy and a low-velocity anomaly originated from the Datong volcano at atop of the asthenosphere are revealed to be subparallel to the Zhangbo fault zone. This observation may be caused by the upwelling magma of the Datong volcano flow into the asthenosphere of the eastern NCC, which also provides new insights into the understanding of the lithospheric thinning of the eastern NCC.

Beschreibung: Sustaining phytoplankton primary production requires the physical supply of nutrients to the thermocline and the mixed layer. In the extensive downwelling regions of the subtropical gyres, the pathways of this nutrient supply remain unclear. Global estimates of mesoscale eddy mixing and internal-wave driven diapycnal mixing and climatological nitrate, salinity, and temperature data are combined to explore the relative importance of microscale turbulence and eddy stirring in supplying nutrients to phytoplankton in the North Atlantic subtropical gyre. The nutrient fluxes by eddy stirring and microscale turbulence are estimated in terms of their advective and diffusive transfers associated with the evolution of a nutrient. Mesoscale eddy stirring and microscale turbulence together supply an average of 0.10 mol N m〈sup〉-2〈/sup〉 yr〈sup〉-1〈/sup〉 to the mixed layer over the gyre. There is substantial spatial variation in the relative importance of the eddy- and turbulence-driven supplies across the gyre, where eddy stirring dominates over microscale turbulence in the northern and south-western gyre and vice versa in the south-eastern gyre. Given the combined nitrate supply by eddy stirring and microscale turbulence to the mixed layer falls short of nitrate export over 90% of the gyre, we suggest that mesoscale eddy stirring and microscale turbulence does not sustain phytoplankton primary production in the subtropical gyres alone. Other mixing mechanisms such as time-varying eddy circulations and double diffusion by salt fingers are expected to be important.

Beschreibung: The accumulation and export of microplastics compose growing negative socio-environmental impacts, which are intensified in coastal and estuarine areas. The Santos Estuarine System set the most populous estuarine region, and with the largest seaport in Brazil, where the movement and accumulation of microplastics is an integrated effect of diverse hydrodynamic conditions. In order to identify the vulnerability of pollution by microplastics, in extreme conditions of elevation and depression of the sea surface in this complex estuarine region, the coupling between Lagrangian and Eulerian modeling was used, an approach that has become popular in the study of movements in the ocean. The trajectories of microplastics from potential sources were modeled using Opendrift, forced by currents from the Eulerian model ECOM, and waves from Wavewatch III. Particle concentrations and three-dimensional stochastic probability of contact with the continent were evaluated, demonstrating that, regardless of the sea surface elevation condition, microplastics are more exported to the South Brazilian Bight than accumulated on the margins and/or bottom of the system. During higher elevations of the sea surface there is greater accumulation of microplastics on the estuary margins, especially in neap tide, but with spring promoting faster transport. Although the entire coastline of Santos and adjacent beaches are prone to the largest accumulations, portions further to the Northeast of the estuary have not shown propensity to be contaminated with microplastics released into estuarine channels. The highest concentrations are actively drifting in the system's water column. This approach used is a pioneer in Brazilian estuarine systems.

Beschreibung: The abundance of airborne iron-bearing particles in anthropogenic settings makes an ideal use case for applying environmental magnetism techniques. The sensitivity of magnetic techniques to mineral composition, oxidation state, morphology, and grain size in the range 10–10〈sup〉4〈/sup〉 nm means that, in principle, it is possible to unmix and distinguish different sources of air pollution. The magnetic properties of particles change fundamentally across this size range and, given the known health risks associated with exposure to iron oxide particulate matter (PM), magnetic methods offer a potentially powerful way to detect and monitor the presence of iron-oxide nanoparticles that may be poorly characterised by traditional methods. Here we show the utility of a range of magnetic techniques—both experimental and modelling. High-resolution room-temperature (RT) and low-temperature (LT) first-order reversal curves (FORCs) are sensitive to grain size, mineralogy, and domain state. We also show the application of thermal fluctuation tomography (TFT) to characterise the grain size distribution in the superparamagnetic (SP) and single-domain (SD) range and the use micromagnetic simulations on PM electron tomography data to ground truth experimental results. We believe complementing environmental magnetism techniques with microscopy (TEM, SEM, and tomography) can give us a greater insight into the characteristics of iron oxide PM. We illustrate these methods using recent case studies from various urban microenvironments — traffic related pollution in Lahore, Pakistan, abrasion related pollution in the London Underground, and the potential use of green infrastructure to reduce child exposure to particulate matter pollution in a school playground in Manchester.

Beschreibung: 〉Hailstorms and climate changeHail is a dangerous phenomenon that regularly causes significant damage and high insured losses around the world. Hailstorms are expected to be affected by climate change, yet the exact nature of these changes remains difficult to quantify and therefore highly uncertain globally. Broadly, a warmer atmosphere would be expected to have higher instability, leading to stronger updrafts that can support larger hailstones; a higher melting-level height, leading to increased melting of smaller hailstones; and reduced overall vertical wind shear, affecting hailstone sizes and storm severity. However, observations and modelling studies worldwide show large geographical variability in these changes and therefore a range of hailstorm responses. Hailstorms, being small-scale and relatively rare, are difficult to observe and to model, meaning there are few long-term datasets suitable for temporal trend analysis, and few projections for future scenarios. There are also gaps in process understanding that complicate efforts to predict changes in hailstorm frequency or severity from changes in other atmospheric variables. In this talk I will present an overview of the current state of knowledge on climate change effects on hailstorms. I will explain how climate change is expected to affect the three factors of instability, microphysical processes, and vertical wind shear. I will review previous results on observed and modelled changes to hailstorms by world region, and explain why uncertainties exist. Finally, I will show recommendations for future study on this important topic.

Beschreibung: We deployed a propulsion system-aided glider in a high current environment off the Florida shelf fitted with an ADCP, a CTD, and optics channel sensors to obtain measurements of current velocities, salinity, temperature, pressure, dissolved organic matter (DOM), chlorophyll, and backscatter. We also used a wave-powered profiling platform, a Wirewalker, fitted with both an ADCP and a CTD to obtain measurements at a 120-m isobath. ADCP velocities from both devices were validated using glider coordinates and overlapping temporal windows for comparisons between dives. Processing of the datasets motion-corrected velocity measurements from both devices. Additionally, the glider optics channels were used to assess differences in particle distributions through time. Wirewalker velocity measurements qualitatively coincided with the glider’s ADCP overall, albeit not perfectly quantitatively. This was partly dependent on whether the upcast or downcast for each dive was compared, as well as distance from the glider. Both ADCPs’ velocity measurements show clear evidence of a southward flowing intermittent undercurrent jet previously reported by Soloviev et al. (2017). The glider’s optics channels also show evidence of the undercurrent, and a possible influx of water from Port Everglades. The volume transport by the southward flow is relatively small compared to the Florida Current’s transport. Nevertheless, the processes that maintain and account for the variability of the southward flow are important for a number of practical applications including the propagation of pollution and genetic information against the Florida Current.

Beschreibung: Predictive uncertainty in hydrological modelling is quantified by using post-processing methods or Bayesian statistical models. The former methods are not straightforward because they combine two models of different nature while the latter methods are not distribution-free. Moreover, calibration of hydrological models is largely based on the squarer error scoring function, or related skill scores and efficiency metrics (e.g. the Nash-Sutcliffe (NSE) and the Kling-Gupta (KGE) efficiencies) that are appropriate when one aims to issue predictions of the mean functional of the probability distribution of the model’s response. To remedy preceding limitations, we propose to move beyond the mean by calibrating and assessing hydrological models with consistent scoring functions. The proposed method is non-parametric, thus the specification of probability distributions in Bayesian settings is not necessary. Furthermore, predictive uncertainty can be estimated directly by calibrating the hydrological model using quantile (or expectile) scoring functions, consequently post-processing residual errors with statistical models is not required. By varying the quantile (or expectile) level of the quantile (expectile) scoring function one can directly simulate pre-specified quantiles (expectiles) of the predictive distribution of the hydrological model’s response. We apply our method to three airGR hydrological models at 511 river basins in the contiguous US. We illustrate the predictive quantiles and expectiles and we show how an honest assessment of the predictive performance of the hydrological models can be made by using consistent scoring functions.

Beschreibung: Kelvin-Helmholtz vortices frequently develop at the magnetopause boundary of planetary magnetospheres where there is a shear in the flow. The nonlinear development of vortices involves coalescence, where smaller vortices combine into larger vortices in an inverse cascade. Simulations also show that in the later stages, the vortex structures are unstable due to the Rayleigh-Taylor instability caused by density gradients, and the coalescing structures can fragment into small scales in a forward cascade. This study examines the nonlinear cross-scale coupling in MHD and hybrid simulations of Kelvin-Helmholtz instability and characterizes the cascade directionality using transfer entropy. We view the polar spectral densities of the simulations to identify the timescales and directionalities of the cascade dynamics. We then perform a windowed transfer entropy analysis of the spectral densities to show how the dynamics of the cascades evolve over time. For each simulation we analyzed, the transfer entropy consistently displayed the inverse and forward cascade interactions we expected from the polar spectral densities, while also highlighting properties of the interactions that were not otherwise apparent. This study provides evidence that nonlinear coupling across scales is important in the turbulent process and demonstrates the usefulness of transfer entropy as a method of analyzing such processes.

Beschreibung: 〉Identifying how energy transfer proceeds from macroscales down to micro-scales in collisionless plasmas is at the forefront of astrophysics and spacephysics. It provides information on the evolution of involved plasma systemsand the generation of high-energy particles in the universe. Here we report twocross-scale energy-transfer events observed by NASA’s Magnetospheric Mul-tiscale spacecraft in Earth’s magnetosphere. In these events, hot ions simul-taneously undergo interactions with macroscale (~105 km) ultra-low-frequencywaves and microscale ( ~ 103 km) electromagnetic-ion-cyclotron (EMIC) waves.The cross-scale interactions cause energy to directly transfer from macro-scales to microscales, and finally dissipate at microscales via EMIC-wave-induced ion energization. The direct measurements of the energy transfer ratein the second event confirm the efficiency of this cross-scale transfer process,whose timescale is estimated to be roughly ten EMIC-wave periods about(1 min). Therefore, these observations experimentally demonstrate thatsimultaneous macroscale and microscale wave-ion interactions provide anefficient mechanism for cross-scale energy transfer and plasma energization inastrophysical and space plasmas

Beschreibung: Appropriate land use policy is essential for flood risk reduction in addition to infrastructure especially under increasing risk due to climate change. In case land use restriction is unavailable, more relaxed approaches are preferred such as subsidies or development of desirable areas; however, their flood risk reduction is harder to assess because demands on such incentives are typically unknown. To quantify the impacts of urban planning policies on people’s migration to safer areas and on the corresponding flood risk reduction, we developed an agent-based model (ABM) of house location choice in a case study of Kyoto, Japan. The ABM simulates the decision making of residence of each household (an agent) and house supply by developers. By quantifying the attractiveness of different areas by available public transportation, the model well represented the market house prices. Using the constructed ABM, the impact of railway development at different locations with different transportation convenience and flood risk on the change of 1000-year flood damage was tested. The result showed that development of low-risk areas fairly attracted and gathered people in safer area, reducing 1000-year flood damage, while the impact was smaller when it comes to low-income people. Developing less convenient area with lower original house price guided low-income people better than developing more convenient area. We demonstrate that careful consideration of development location affects resulting flood risk.

Beschreibung: Rewetting previously drained peatlands restores the critical function of peatlands as long-term carbon storages and sinks currently threatened by climate change and additional human-induced disturbances. Understanding and projecting the restoration process by rewetting, however, currently face a pressing challenge, the lack of consistent and gap-free records of important carbon cycling indicators of peatlands such as the gross primary production (GPP) over long term. In this study, we reconstructed the GPP in a rewetted peatland called Zarnekow (Fluxnet-ID: DE-Zrk) in Germany from 2000 to 2020 by combining long-term satellite observations and limited-term tower-based eddy covariance (EC) measurements based on Random Forest regression models. The R2 between the reconstructed data and EC data was 0.6. The reasonable reconstruction of long-term GPP enabled trend analysis that identified two distinct periods of decreasing/increasing in GPP due to rewetting and droughts. Rewetting in the winter of 2004 and 2005 stabilized GPP after a decreasing period. A drought in 2018 significantly increased GPP, and GPP remained high over the following two years. Furthermore, the month-specific trends show significant seasonality at this site, specifically, an increasing trend over the 21 years in the growing-season months of June to August and a decreasing trend in the other months. The most important variables for satellite-based estimates of GPP at this site include total evapotranspiration, land surface temperature, enhanced vegetation index and near-infrared reflectance vegetation index. Long-term analyses of carbon fluxes through the combination of satellite observations and EC measurements provide crucial insights into the restoration of carbon sequestration functions in rewetted peatlands.

Beschreibung: Fold-and-thrust belts (FTBs) develop widely in and around active orogenic belts on Earth. With the accumulation of structural shortening, thrust-related folds can grow by increasing their amplitudes and lengths, providing insights into the structural evolution of FTBs. Investigations of fold growth patterns and landscape responses through time and space have important implications for hydrocarbon exploration and geo-hazard assessment. Evidence for lateral fold propagation (i.e., increase in length) usually comes from geochronological constraints based on differences in onset timings along strike. However, these traditional methods are time consuming and economically costly. Alternatively, previous studies have proposed the use of geomorphic features to investigate the lateral fold propagation, including spatial variations in the patterns and densities of river channels, the configuration of the topographic profile along the fold crest, and the occurrence of wind gaps. However, such analyses are based on morphological features of present-day landscapes, which still need process-based validations. Here, we conduct a series of landscape evolution models to reproduce fold growth and their associated geomorphic adjustments. Our results show that deflected rivers and inflected fold-crest elevation profile with decreasing gradient are reliable evidence of lateral fold propagation. The location of propagation is in accordance with the distribution of crest-profile slope breaks and the position where river deflection began. Then, we apply these findings to two natural examples located at the deformation fronts of the Tian Shan (NW China). Results suggest that 1) the Kashi anticline has experienced lateral propagation both westwards and eastwards; and 2) that the Yaken anticline has experienced accelerated tectonic uplift as well as eastwards propagation. These findings are supported by the constraints from geochronological dating and quantitative structural analysis. Future work that integrates folding mechanisms may provide novel insights into landscape response to complex deformation in active FTBs.

Beschreibung: Understanding ENSO diversity and its response to external climate forcings is not only critical for accurate prediction of global ENSO impacts but can also be used as a tool to constrain future global climate projections. Considering model skill in simulating ENSO diversity can reduce model uncertainty in both ENSO response and the mean state of the tropical Pacific, as well as the associated impacts on precipitation patterns, tropical cyclones, extratropical circulation, etc. (Karamperidou et al. 2017; Wyman, Conroy & Karamperidou, 2020). However, groundtruthing model simulations of ENSO diversity is challenged by the short length of the instrumental record, which necessitates using paleoclimate proxy records from across the Pacific and interpreting them within the context of ENSO diversity (Karamperidou et al., 2020; Karamperidou & DiNezio, 2022). In this talk, I will present a series of studies that explore the dynamics of ENSO flavors across climates (Karamperidou & DiNezio, 2022), including coastal El Nino events (Zhao & Karamperidou, 2022), and their impacts on extreme hydroclimate phenomena (Kiefer & Karamperidou, 2019; McKenna & Karamperidou, 2023). These studies use a multi-resolution and hierarchical approach and combine dynamical with statistical and machine learning approaches for improving understanding of past and future ENSO behavior and the complexity of its global impacts.

Beschreibung: Geomagnetically induced currents (GICs) are induced in electrical power transmission networks during geomagnetic disturbances, driven by storm-induced geoelectric fields. Understanding the magnitude and duration of the GIC expected during worst-case extreme storm scenarios is vital for future planning. In this study we utilize the magnetic field time-variation measured during three large geomagnetic storms and scale them to expected worst case extreme storm magnitudes, based on the UK realistic worst case scenario. Multiple methods are used to simulate the varying magnitude of the magnetic, and hence geoelectric fields across the different latitudes of New Zealand. Our modelling approach produces geoelectric fields which have been scaled to reproduce observed GIC in tens of different transformers and substations over a wide range of the country. Modelled GIC is produced for nine extreme storm scenarios, each covering 1-1.5 days in duration. Our industry partners, Transpower New Zealand Ltd provided GIC magnitude and duration levels which represent a risk to their transformers. Using these thresholds various extreme storm scenarios predict between 44 and 115 New Zealand transformers (13-35%) are at risk of damaging levels of GIC. The transformers at risk are largely independent of the extreme storm time-variations, but depend more on the latitude variation scenario. We show that these at-risk transformers are not localized to any specific region of New Zealand but extend across all latitudes. We believe this is one of the first studies to combine a reasonable worst-case extreme geomagnetic storm with validated GIC modelling and industry-provided GIC risk thresholds.

Beschreibung: Contemporary general circulation models (GCMs) and Earth system models (ESMs) are developed by a large number of modeling groups globally. They use a wide range of representations of physical processes, allowing for structural (code) uncertainty to be partially quantified with multi-model ensembles (MMEs). Many models in the MMEs of the Coupled Model Intercomparison Project (CMIP) have a common development history due to sharing of code and schemes. This makes their projections statistically dependent and introduces biases in MME statistics. Previous research has focused on model output and code dependence, and model code genealogy of CMIP models has not been fully analyzed. We present a full reconstruction of CMIP3, CMIP5 and CMIP6 code genealogy of 167 atmospheric models, GCMs, and ESMs (of which 114 participated in CMIP) based on the available literature, with a focus on the atmospheric component and atmospheric physics. We identify 12 main model families. We propose family and code weighting methods designed to reduce the effect of model structural dependence in MMEs. We analyze weighted effective climate sensitivity (ECS), climate feedbacks, forcing, and global mean near-surface air temperature, and how they differ by model family. Models in the same family often have similar climate properties. We show that weighting can partially reconcile differences in ECS and cloud feedbacks between CMIP5 and CMIP6. The results can help in understanding structural dependence between CMIP models, and the proposed code and family weighting methods can be used in MME assessments to ameliorate model structural sampling biases.

Beschreibung: Freshwater - a fragile resource - is essential for life, development, and the environment. The Senegal River is a strategic region for the socio-economic development of these countries. The Senegal River's water management in time and space is possible thanks to the existing and future hydropower reservoirs. Hydropower is the world's largest and most widely used renewable energy source. In the future, hydropower is expected to be profoundly impacted due to the changes in river flow caused by climate change. This study examined the impact of climate change on the hydropower potential in the Senegal River basin for the periods P2 (2035-2065) and P3 (2065-2095) compared to P1 (1984-2014) under ssp 126 and ssp 370. We found that for P2, compared to P1, an increase of 6% in the annual flow would lead to an increase of 3% in annual hydropower generation for the ssp 126. A decrease of -1% in annual flow would reduce -0.7% in annual hydropower generation for the ssp 370. For P3 compared to P1, a reduction of annual flow by -6% and -13% would cause a decrease of -8% and -14% in annual hydropower, respectively, for ssp 126 and ssp 370. The planned reservoirs would increase the surface water storage, but it would cause a loss of -11% of the hydropower of the existing reservoir. Therefore, it is crucial to develop new adaptation techniques by combining hydro, solar and wind energy to mitigate the effects of climate change.

Beschreibung: There is significant and growing interest in the coupling of radiation belt electrons into the upper atmosphere through energetic electron precipitation (EEP). As well as being one of the competing processes driving the dynamic radiation belts, EEP has been linked to significant changes in the chemical composition of the stratosphere and mesosphere potentially playing a role in regional climate variability. Because of these findings, recent efforts have been made to incorporate EEP into climate modelling codes and to better understand electron precipitation measurements from spacecraft and ground-based instruments. As one might expect, the most accurate EEP forcing in such climate chemistry modelling codes comes from directly incorporating satellite measurements of EEP fluxes. However, this approach is strongly limited by the time periods in which such satellite observations have existed, as well as characteristics of the flux measurements (particularly energy resolution and sensitivity). As such, a number of researchers have made use of geomagnetic proxies to produce empirical EEP forcing representations suitable for incorporation in the modelling codes - allowing periods outside the current era to be modelled. We make use of 3 different satellite datasets (DEMETER, POES, and SAMPEX) to examine the suitability of different geomagnetic and solar wind proxies to represent EEP fluxes. While some of those datasets are globally limited to drift loss cone fluxes, we focus on observations made in the North Atlantic where the fluxes measured are locally precipitating.

Beschreibung: The frequency of large-scale anomalous precipitation events associated with heavy precipitation has been increasing in Japan. However, it is unclear if the increase is due to anthropogenic warming or internal variability. Also, it is challenging to develop an objective methodology to identify anomalous events because of the large variety of anomalous precipitation cases. In this study, we applied a deep learning technique to objectively detect anomalous precipitation events in Japan for both observations and simulations using high-resolution climate models. The results show that the observed increases in anomalous heavy precipitation events in Western Japan during 1977–2015 were not made only by internal variability but the increases in anthropogenic forcing played an important role. Such events will continue to increase in frequency this century. The increases are attributable to the increasing frequency of tropical cyclones and enhanced frontal rainbands near Japan. These results highlight the mitigation challenge posed by the increasing occurrence of unprecedented precipitation events in the future.

Beschreibung: A severe flooding hit the region of central east China to southern Japan in summer 2020. It is found that the extremely strong rainfall experienced pronounced subseasonal variation, dominated by a quasi-biweekly oscillation (QBWO) mode. The analysis of streamfunction of water vapor flux demonstrates that a large amount of water vapor eastward zonal transport from the Bay of Bengal and Indo-China and northward transport from the South China Sea provided the background moisture supply for the rainfall. The quasi-biweekly anomalies of potential and divergent component of vertically integrated water vapor flux played an important role in maintaining the subseasonal variability of extreme rainfall. The diagnosis of moisture tendency budget shows that the enhanced moisture closely related to the quasi-biweekly fluctuated rainfall was primarily attributed to the moisture convergence. Further analysis of time-scale decomposition in the moisture convergence indicates that the convergence of background mean specific humidity by the QBWO flow and convergence of QBWO specific humidity by the mean flow played dominant roles in contributing to the positive moisture tendency. In combination with adiabatic ascent over the rainfall region induced by the warm temperature advection, the boundary layer moisture convergence strengthened the upward transport of water vapor to moisten the middle troposphere, favoring the persistence of rainfall. The vertical moisture transport associated with boundary layer convergence was of critical importance in causing low-level tropospheric moistening.

Beschreibung: Methanogenic archaea are a diverse, polyphyletic group of strictly anaerobic prokaryotes capable of producing methane as their primary metabolic product. It has been over three decades since minimal standards for their taxonomic description have been proposed. In light of advancements in technology and amendments in systematic microbiology, revision of the older criteria for taxonomic description is essential. Most of the previously recommended minimum standards regarding phenotypic characterization of pure cultures are maintained. Electron microscopy and chemotaxonomic methods like whole-cell protein and lipid analysis are desirable but not required. Because of advancements in DNA sequencing technologies, obtaining a complete or draft whole genome sequence for type strains and its deposition in a public database are now mandatory. Genomic data should be used for rigorous comparison to close relatives using overall genome related indices such as average nucleotide identity and digital DNA–DNA hybridization. Phylogenetic analysis of the 16S rRNA gene is also required and can be supplemented by phylogenies of the mcrA gene and phylogenomic analysis using multiple conserved, single-copy marker genes. Additionally, it is now established that culture purity is not essential for studying prokaryotes, and description of Candidatus methanogenic taxa using single-cell or metagenomics along with other appropriate criteria is a viable alternative. The revisions to the minimal criteria proposed here by the members of the Subcommittee on the Taxonomy of Methanogenic Archaea of the International Committee on Systematics of Prokaryotes should allow for rigorous yet practical taxonomic description of these important and diverse microbes.

Beschreibung: Process-based numerical models of sediment yields from river basins rely on an accurate representation of hillslope sediment supply and transport processes, both of which are driven by dynamic climatic forcing (precipitation and temperature). The complex relations between climatic forcing and sediment mobilization at the basin scale result in predictions of sediment yield that are highly uncertain, at times enhancing, then dampening environmental signals, such as effects of climate change. Here, we present what we think are two main challenges in the prediction of sediment yields in a future climate – the unknown effect of sediment supply and the non-uniqueness that appears due to many sediment sources. Using two geomorphic models – a conceptual sediment cascade model and a distributed physically-based hydrology-sediment model – in an Alpine environment, we show that (a) sediment supply is likely to be a critical factor for sediment yield estimation, and how future climate affects this supply may be much more important than the effects of hydrologic forcing on sediment transport in some geomorphic systems; and (b) very similar sediment yields may be generated by completely different combinations of sediment sources, leading to difficulties in model validation. We lay out some ideas for how to solve these problems, e.g. by recognizing sediment supply limitations in simulations, by tracing sediment provenance from distinct sources in models, and also by new types of field observations. We are convinced such challenges need to be taken up by modelers to improve the confidence in sediment predictions under climate change.

Beschreibung: Flood damages are linked to the maximum water elevation and extension that they can reach. These characteristics depend on streamflows and spatial configuration of the water body and floodplain. Flood studies often assume bathymetry as a permanent characteristic, yet it varies through natural processes, which can generate uncertainties in flood estimations. This research uses four bathymetry instances of a lake, distributed over three decades, to analyse their effect on water levels and extension during flood events. We use six past flood events at the study site (Trois-Lacs) in the form of hydrographs obtained with Hydrotel, a distributed physics-based hydrological model. We then used Telemac2D to run unsteady flow simulations with the different bathymetries. Results show water level differences between bathymetries under 0.13m for peak flows (exceedance probability under 0.04%), while for regular flows (exceedance probability between 32% and 68%) differences can be as great as 0.46m. Variations in flooded areas for peak flows show up to 2% differences, and for regular flows differences amount to 13%. This shows that different bathymetries produce considerable variations on water levels and flooded areas during periods of average flows, and less so for maximum flows. These results indicate that modifications of the bed of the water body should be considered when performing flow simulations and related studies, since they can convey larger flood extents during periods of normal (non-extreme) meteorological conditions. This could provide users and decision makers with more robust information about the uncertainties and probable variations of floods.

Beschreibung: In north Greenland, which holds more than 2.7 m of sea level equivalent, the ice flows through ice shelves, as in Antarctica. These floating platforms are the most vulnerable parts of the ice sheets as the advection of warm, salty ocean waters increases basal melting, which can trigger an increase in ice flow into the ocean. Here we study the recent dynamic and geometric changes of all present and former ice shelves along the north coast of Greenland. We document the evolution of the surface elevation using data from the GIMP project, from NASA's instruments (ICESat-1/2, ATM, LVIS, GLISTIN-A) and generate DEMs using ASTER imagery between 2000-present. We also monitor changes in surface ice velocity and grounding zone evolution using a combination of optical and radar data. We use the elevation time series to monitor the temporal evolution of the ice shelves volumes and combine them with the surface flow velocity to calculate basal melt rates in a Lagrangian framework at unprecedented level of resolution. Finally, we compare our observations with nearby CTD measurements, the TOPAZ4b reanalysis of Arctic ocean physics provided by Copernicus Marine Service and model outputs from the Modèle Atmosphérique Régoinal. We show that basal melting, grounding line retreat and fracturing are rapidly increasing and is followed by an increase in ice discharge into the ocean. These observations demonstrate that significant changes are occuring in a region that has long been considered stable, which may have dramatic consequences for the ice sheet contribution to sea level rise.

Beschreibung: We have studied the high-pressure vibrational and structural behavior of bulk graphite and graphene nanoplatelets at room temperature by means of high-pressure Raman spectroscopic and x-ray diffraction probes. We have detected a clear pressure-induced structural transition in both materials, evidenced by the appearance of new Bragg peaks and Raman features, deviating from the starting hexagonal graphitic structure. The high-pressure phase is identified as a partially disordered orthorhombic structure, consisting of mixed sp2- and sp3-type bonding. Our experimental findings serve as direct evidence for the existence of a metastable transient modification in cold compressed carbon, lying between the sp2-type graphite and sp3-type diamond allotropes.

Beschreibung: The Mediterranean Sea is well-known for its sensitivity to climate change, leading to extensive efforts in monitoring the basin as a whole. However, the Mediterranean is composed of individual sub-basins that exhibit different roles in its conveyor belt’s function. Additionally, impacts on societies and ecosystems have been shown to depend primarily on local manifestation of global-scale changes. Thus, sufficient risk assessment and the development of feasible adaptation strategies require regional studies, especially in sub-basins with high population density along their coastlines. The Tyrrhenian basin, one of the main mixing areas of the Mediterranean, is among the most densely populated semi-enclosed basins, yet it remains the least investigated. This work addresses this issue and provides new regional products, implementing information about the state, long-term variability, and changes in the surface and sub-surface layers of the Tyrrhenian Sea, while considering the potential role of local forcing as well as large-scale climatic patterns. Essential surface monitoring indicators, such as sea surface temperature, sea level anomaly, geostrophic currents, and air-sea interactions, were assessed using satellite, reanalysis, and in-situ data over the last four decades. Corresponding sub-surface indicators, including ocean heat and salt contents and water mass physical properties, were also computed based on more than 750000 hydrographic stations. A dedicated website was created to distribute these indicators, the regional dataset and the corresponding climatologies in order to respond to the increasing needs for directly usable regional products and to provide a reference baseline for the Tyrrhenian Sea.

Beschreibung: Magnetotail is one of the most critical regions of the Earth’s magnetosphere. Its dynamics are controlled by the external solar wind and IMF conditions, the coupling with the ionosphere, and the transport and energization of particles from the solar wind and ionosphere. It provides the main particle sources for the inner magnetosphere. This presentation reviews advances made in the last two years from observations and simulations in our understanding of the magnetotail dynamics. The topics include, but not limited to, large-scale magnetotail structures, mesoscale disturbances, tail reconnection physics, substorms, ionospheric outflows, and connection with the inner magnetosphere.

Beschreibung: Bering Strait transport is a key source of heat, freshwater, and nutrients for the Arctic. Moored observations indicate that transport has been increasing over the last decades. Recently, Danielson et al. (2020) have proposed a feedback mechanism by which increased sea surface temperatures (SST) in the Chukchi Sea would drive stronger ocean to atmosphere heat fluxes in fall, leading to anomalously strong winds to the North over the Bering Strait, and thus increased Bering Strait heat and volume fluxes. We investigate this hypothesis with a combination of observations and modeling. First, we inspect reanalysis products to interrogate whether the observed trends support the proposed feedback mechanism. Next we investigate the response of an ocean model to reanalysis forcing, looking for evidence of whether this response can be detected for such simulations. Results indicate that the proposed increase in northward wind stress over the Bering Strait is highly localized in space and only significant in October, despite robust trends in SST and surface heat fluxes. Simulations do not replicate the positive trend in Bering Strait volume transport and raise the question as to whether increases in local winds are indeed responsible? To test this hypothesis, the same ocean model is forced with additional localized northward wind perturbations to determine the strength and persistence of surface forcing required to reproduce the observed trend in Bering Strait ocean transport. The transport response to a range of wind perturbation experiments will be presented and the limitations and implications of this research will be discussed.

Beschreibung: The Southern Ocean, which covers one-third of the total ocean area, is a primary sink for anthropogenic heat and carbon globally. Since 1960, an obvious freshening signal in the Southern Ocean has been observed and is suggested to be driven by anthropogenic climate change. The physical drivers and processes responsible for these salinity changes, however, are poorly understood, owing to sparse observations in the Southern Ocean. In this study, we conduct perturbation experiments based on a global ocean sea ice model to separate the roles of surface forcing (i.e., freshwater flux, heat flux and wind stress) in the Southern Ocean salinity changes since 1960. Moreover, we decomposed salinity into its heave and spiciness components to understand the salinity changes along and across isopycnals, under different atmospheric forcing. The result shows the surface freshwater flux freshens the surface ocean, reduces vertical mixing and ventilation, and dominates the structure of freshening between 45〈sup〉o〈/sup〉-65〈sup〉o〈/sup〉S. Poleward-intensifying winds, on the contrary, increase mixing, strengthen deep water ventilation and mode water formation, and therefore promote upwelling of saltier subsurface water that can offset the freshening driven by freshwater flux. This study provides a quantitative estimate of distinct impacts of individual surface forcing on ocean salinity, helping to better understand the observed and projected salinity changes in the Southern Ocean. Further research is needed to understand the different processes that dominate different ocean sections.

Beschreibung: To calibrate airborne gravity gradiometers under development in China, it is urgent to build an airborne gravity gradiometer test site. The site’s selection depends on the preknowledge of high-resolution gravity and gradient structures. The residual terrain modelling (RTM) technique is generally applied to recover the short-scale gravity field signals. Limited by the quality and resolution of density models, RTM terrain generally assumes a constant density. This would involve great errors over areas with large density anomalies, such as volcano areas. This study determines a high-resolution gravity field by combining the long-wavelength signals generated by EGM2008, short-scale signals of RTM with constant density, and gravity signals of density anomalies. The density anomalies are obtained through the equivalent source method (EQS) from sparse terrestrial gravity measurements. Compared to the recovery rate of 54.62% using the classical RTM method, the recovery rate increases to 86.22% after involving density anomalies. With this method, the gravity field signals over Wudalianchi Volcano Field (WVF) on the Earth's surface and at a flight height of 100 m above terrain are investigated. The contribution of each part and their attenuation characters are studied. The 5 km*5 km area around Bijiashan and Wohushan volcanos shows a strong gravity signature which is recommended for the test site. This study gives the location of the airborne gravity gradiometer test site which is an essential step in the instruments’ development. Besides, the method in this study will provide an initial foundation methodology for future data processing over the test site.

Beschreibung: Taiwan is located on a convergent boundary of the Eurasian Plate and the Philippine Sea Plate. It is one of the countries that have experienced the most earthquakes worldwide. The eastern region of Taiwan is directly above the collision zone and is the most frequent and active with domestic earthquake activity. The areas also have dense dynamic fault systems which located in the Yilan, Hualien, and Taitung areas. Those areas record huge amount of earthquakes yearly. Since seismic b-value has been investigated in different periods throughout Taiwan in the past, they have not yet to study the b-value of the eastern region of Taiwan in detail. Therefore, this study uses the earthquake catalog integrated by the Central Weather Bureau to analyze the spatial-temporal variations of b-values in east Taiwan. The seismic events recorded from January 1996 to June 2019 are adopted. Areas with a low seismic b-value often represent potential areas where major earthquakes are likely to occur. Our results indicate that in eastern Taiwan, the overall b-value has generally demonstrated a decreasing trend in recent years. The rapid re-accumulation of internal stress possibly caused by the compression of the two plates and the ongoing seismogenic behavior. The potential for a catastrophic earthquake is exceptionally high. Therefore, we should act appropriately at any time.

Beschreibung: On Saturday the 1〈sup〉st〈/sup〉 of September 1923 at a few minutes to noon, when the Kanto earthquake occurred, the foreign population of the harbor of Yokohama reached 2,500 people of different nationalities, and a similar presence was in Tokyo, which as the capital hosted the officers of embassies, consulates and trade companies. These foreign residents left impressive records of the earthquake occurrence, as well as the fire and tsunami that followed. As far as we could ascertain, their accounts have not been used yet to compile either the official reports or the published monographs on social and scientific aspects, works that mostly relied on and referenced the news press and official Japanese statements. To add a different viewpoint to the overall understanding of this earthquake, we concentrated on the considerable quantity of documents now stored at The National Archives (Kew Gardens, UK) and at the Affaires Etrangers-Archives Diplomatique (La Corneuve, Paris, France) produced by British and French diplomats as well as foreign residents of different nationalities who were in Yokohama and Tokyo at the time of the earthquake. The most significant testimonies from both cities are presented and compared, and the role in the relief actions of the British Royal Navy and of ships of other countries are put in the foreground. The immediacy of the descriptions they contain and the details they supply bring us back to the shaking and shocking moments experienced by the people living in Yokohama and Tokyo one hundred years ago.

Beschreibung: We investigated the variability in Equatorial electrojet (EEJ) and Counter electrojet (CEJ) characteristics at Indian equatorial station Tirunelveli (TIR) using low-latitude geomagnetic conjugate sites Hyderabad (HYB) and GAN Island (GAN) from the northern and southern hemispheres respectively. A significant difference in the amplitudes, more than 10nT for 43% of the days, is observed between the EEJ extracted at TIR using the TIR-HYB pair and the TIR-GAN pair, similarly, a difference of more than 40% in the total numbers of CEJs is noted. Further, the strong correlation coefficient of 0.9 obtained from the monthly mean peaks of diurnal variations in H between TIR and GAN implies the seasonal pattern of the total current at these sites is similar compared to TIR and HYB, where the correlation coefficient is reduced to 0.66. The correlation coefficient from the first principal components of H, at these sites shows variability with seasons, a good correlation is observed between TIR and GAN except for northern winter, for which good correlations are observed for the TIR and HYB pair; this indicates that the total current at the equatorial region is coupled with Sq of either the northern or southern hemisphere and varies with seasons. The present study confirms that the extraction of EEJ/CEJ using Sq from only one hemisphere will lead to biased results and most suitable Sq approximation at equatorial sites should be decided based on the similarity in the seasonal pattern.

Beschreibung: Recently, there has been a surge in the utilization of machine learning algorithms in the field of reservoir characterization studies, reflecting a growing interest in the area. The development and application of novel machine-learning methods are crucial for optimizing production by addressing complex reservoir challenges. Here, an attempt is made to shed light on the application of novel machine learning algorithms to infer permeability, a vital property of reservoir rock. Case examples of a few different reservoir systems will be discussed to critically analyze the performance of machine learning tools and their predictability in petrophysical attribute characterization using wireline log data. Further, parametric sensitivity analysis is conducted to identify the influential predictor variable most relevant for the efficient predictive model. This study aims to benefit readers by highlighting existing gaps in reservoir characterization studies and the potential application of machine learning algorithms for reservoir rock property estimation with much accuracy.

Beschreibung: Glaciers in the Tien Shan mountains supply meltwater for irrigation, industry and drinking to the arid lowlands of among others Kyrgyzstan and Kazakhstan. When snowmelt is depleted and precipitation is absent, the proportion of meltwater from ice masses to river discharge can reach more than 50% (typically in July). Therefore, it is crucial to understand how ice masses in the Tien Shan are reacting to climate change and how they will evolve in the future. For individual glaciers, detailed 3D ice flow models can be calibrated and applied. For regional studies, and because necessary detailed input data is largely lacking, flowline models that rely on various parametrisations, such as GloGEMflow, are used to model glaciers. However, only a limited number of in-depth studies have been performed to assess the accuracy and applicability of such large-scale models. In this study, we compare the glacier evolution for six well-studied ice masses as modelled with (i) a 3D ice flow model and (ii) the large-scale GloGEMflow model. Our analysis suggests that differences in ice volume obtained by 2100 from the 3D HO-model and GloGEMflow are generally limited and that these can mainly be explained by the calibration data.

Beschreibung: Decompression in the magma chamber due to rapid magma extraction triggers caldera collapse. The roof rock overlying the magma chamber is detached by the development of a ring fault, and then it subsides into the magma chamber by the differential pressure between the lithostatic in the roof and magmatic in the chamber. The subsidence of caldera blocks into the magma chamber causes rapid magma extrusion from the magma chamber resulting the eruption of voluminous ignimbrite. Therefore, magma chamber decompression is the key to understanding the evolution of caldera-forming eruptions (CFE). Here, we examine the decompression process of the magma chamber during CFE based on the sequential variation of the volatile contents in the glass inclusions in the products of several CFEs. We find that some CFEs experienced large magma chamber decompression toward the caldera collapse, whereas some start to collapse with minor decompression in the magma chamber. This variation may represent differences in the fracture strength of the roof rock of the magma chamber. Shallow magma chambers with thin roof rock will collapse with small decompression, whereas deep magma chambers with thick roof rock require larger decompression for caldera collapse. Since the decompression of the magma chamber depends on the volume fraction of magma erupted before the caldera collapse, the structure of the magma chamber, such as the thickness of the roof rock, may be used to predict the variation in the eruption patterns towards the onset of caldera collapse and the eruption of voluminous ignimbrites.