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  • 1
  • 2
    Monograph non-lending collection
    Monograph non-lending collection
    Leiden : Nijhoff ; 1.2009 -
    Call number: IASS 17.92082
    Type of Medium: Monograph non-lending collection
    ISSN: 1876-8814
    Language: English
    Branch Library: IASS Library
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  • 3
    Monograph available for loan
    Monograph available for loan
    Garmisch-Partenkirchen : Institut für atmosphärische Umweltforschung der Fraunhofer- Gesellschaft
    Call number: MOP 44829 / Mitte
    Type of Medium: Monograph available for loan
    Pages: 25 S. , graph. Darst.
    Language: English
    Location: MOP - must be ordered
    Branch Library: GFZ Library
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  • 4
    Monograph available for loan
    Monograph available for loan
    [Edgecumbe, N.Z.] : A. Muller
    Call number: M 15.89146
    Description / Table of Contents: An account of the results of the 2 March 1987 earthquake in the eastern Bay of Plenty and the aftermath's effects on the people and places on the Rangitaiki Plains
    Type of Medium: Monograph available for loan
    Pages: 223 S., , Ill.
    Language: English
    Branch Library: GFZ Library
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  • 5
    Call number: Z 06.0500
    Type of Medium: Journal available for loan
    Pages: 30 cm
    ISSN: 1824-7741
    Former Title: Vorgänger Geologisch-paläontologische Mitteilungen, Innsbruck
    Language: German , English
    Note: Ersch. unregelmäßig , Beiträge teilweise in Englisch
    Branch Library: GFZ Library
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  • 6
    Monograph available for loan
    Monograph available for loan
    London : Penguin Books
    Type of Medium: Monograph available for loan
    ISBN: 9780141985206
    Language: English
    Branch Library: IASS Library
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  • 7
    Journal available for loan
    Journal available for loan
    Tübingen : Mohr Siebeck ; 1.1884 - 48.1931; N.F. 1.1932/33 - 10.1943/44(1945),3; 11.1948/49(1949) -
    Call number: ZS 22.95039
    Type of Medium: Journal available for loan
    Pages: Online-Ressource
    ISSN: 1614-0974 , 0015-2218 , 0015-2218
    Language: German , English
    Note: N.F. entfällt ab 57.2000. - Volltext auch als Teil einer Datenbank verfügbar , Ersch. ab 2000 in engl. Sprache mit dt. Hauptsacht.
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  • 8
    Monograph available for loan
    Monograph available for loan
    Stuttgart : Schweizerbart Science Publishers ; Volume 1, number 1 (1978)-
    Call number: M 18.91571
    Type of Medium: Monograph available for loan
    Pages: 134 Seiten
    ISSN: 2363-7196
    Series Statement: Global tectonics and metallogeny : special issue Vol. 10/2-4
    Classification:
    Tectonics
    Parallel Title: Erscheint auch als Global tectonics and metallogeny
    Language: English
    Location: Upper compact magazine
    Branch Library: GFZ Library
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  • 9
    Call number: 3/S 07.0034(2017)
    In: Annual report
    Type of Medium: Monograph available for loan
    Pages: 51 Seiten
    ISSN: 1865-6439 , 1865-6447
    URL: Volltext  (kostenfrei)
    Parallel Title: Annual report ... / Helmholtz Association of German Research Centres
    Language: English
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  • 10
    Publication Date: 2023-10-20
    Description: Trawl-fishing is broadly considered to be one of the most destructive anthropogenic activities toward benthic ecosystems. In this study, we examine the effects of bottom-contact fishing by otter trawls on the geochemistry and macrofauna in sandy silt sediment in an area of the Baltic Sea where clear spatial patterns in trawling activity were previously identified by acoustic mapping. We calibrated an early diagenetic model to biogeochemical data from various coring locations. Fitting measured mercury profiles allowed for the determination of the sediment mixing and burial velocity. For all sites, independent of the trawl mark density, good fits were obtained by applying the model with the same organic matter loading and parameter values, while iron fluxes scaled linearly with the burial velocity. A sensitivity analysis revealed that the fitted sulfate reduction rate, solid sulfur contents, ammonium concentration, and both the isotopic composition and concentration of dissolved inorganic carbon provided reliable constraints for the total mineralization rate, which exhibited a narrow range of variability (around ±20 % from the mean) across the sites. Also, the trawling intensity did not significantly correlate with total organic carbon contents in surficial sediment, indicating limited loss of organic matter due to trawling. The fits to the reactive iron, acid volatile sulfur, chromium(II) reducible sulfur contents, and porewater composition demonstrate that sediment burial and mixing primarily determine the redox stratification. The mixing depth did not correlate with trawling intensity and is more likely the result of bioturbation, as the analyzed macrofaunal taxonomy and density showed a high potential for sediment reworking. The extraordinarily long-lived Arctica islandica bivalve dominated the infaunal biomass, despite the expectation that trawling leads to the succession from longer-lived to shorter-lived and bigger to smaller macrofauna. Our results further suggest that a clear geochemical footprint of bottom-trawling may not develop in sediments actively reworked by tenacious macrofauna.
    Language: English
    Type: info:eu-repo/semantics/article
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  • 11
    Publication Date: 2023-01-12
    Description: 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.
    Language: English
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  • 12
    Publication Date: 2023-01-12
    Description: 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.
    Language: English
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  • 13
    Publication Date: 2023-01-09
    Description: 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.
    Language: English
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  • 14
    Publication Date: 2023-01-10
    Description: 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.
    Language: English
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  • 15
    Publication Date: 2023-01-10
    Description: Earth observation satellite data acquired in recent years and decades provide an ideal data basis for accurate long-term monitoring and mapping of the Earth's surface and atmosphere. However, the vast diversity of different sensor characteristics often prevents synergetic use. Hence, there is an urgent need to combine heterogeneous multi-sensor data to generate geometrically and spectrally harmonized time series of analysis-ready satellite data. This dissertation provides a mainly methodical contribution by presenting two newly developed, open-source algorithms for sensor fusion, which are both thoroughly evaluated as well as tested and validated in practical applications. AROSICS, a novel algorithm for multi-sensor image co-registration and geometric harmonization, provides a robust and automated detection and correction of positional shifts and aligns the data to a common coordinate grid. The second algorithm, SpecHomo, was developed to unify differing spectral sensor characteristics. It relies on separate material-specific regressors for different land cover classes enabling higher transformation accuracies and the estimation of unilaterally missing spectral bands. Based on these algorithms, a third study investigated the added value of synthesized red edge bands and the use of dense time series, enabled by sensor fusion, for the estimation of burn severity and mapping of fire damage from Landsat. The results illustrate the effectiveness of the developed algorithms to reduce multi-sensor, multi-temporal data inconsistencies and demonstrate the added value of geometric and spectral harmonization for subsequent products. Synthesized red edge information has proven valuable when retrieving vegetation-related parameters such as burn severity. Moreover, using sensor fusion for combining multi-sensor time series was shown to offer great potential for more accurate monitoring and mapping of quickly evolving environmental processes.
    Description: Die in den letzten Jahrzehnten aufgenommenen Satellitenbilder zur Erdbeobachtung bieten eine ideale Grundlage für eine genaue Langzeitüberwachung und Kartierung der Erdoberfläche und Atmosphäre. Unterschiedliche Sensoreigenschaften verhindern jedoch oft eine synergetische Nutzung. Daher besteht ein dringender Bedarf heterogene Multisensordaten zu kombinieren und als geometrisch und spektral harmonisierte Zeitreihen nutzbar zu machen. Diese Dissertation liefert einen vorwiegend methodischen Beitrag und stellt zwei neu entwickelte Open-Source-Algorithmen zur Sensorfusion vor, die gründlich evaluiert, getestet und validiert werden. AROSICS, ein neuer Algorithmus zur Co-Registrierung und geometrischen Harmonisierung von Multisensor-Daten, ermöglicht eine robuste und automatische Erkennung und Korrektur von Lageverschiebungen und richtet die Daten an einem gemeinsamen Koordinatengitter aus. Der zweite Algorithmus, SpecHomo, wurde entwickelt, um unterschiedliche spektrale Sensorcharakteristika zu vereinheitlichen. Auf Basis von materialspezifischen Regressoren für verschiedene Landbedeckungsklassen ermöglicht er nicht nur höhere Transformationsgenauigkeiten, sondern auch die Abschätzung einseitig fehlender Spektralbänder. Darauf aufbauend wurde in einer dritten Studie untersucht, inwieweit sich die Abschätzung von Brandschäden aus Landsat mittels synthetischer Red-Edge-Bänder und der Verwendung dichter Zeitreihen, ermöglicht durch Sensorfusion, verbessern lässt. Die Ergebnisse zeigen die Effektivität der entwickelten Algorithmen zur Verringerung von Inkonsistenzen bei Multisensor- und Multitemporaldaten sowie den Mehrwert einer geometrischen und spektralen Harmonisierung für nachfolgende Produkte. Synthetische Red-Edge-Bänder erwiesen sich als wertvoll bei der Abschätzung vegetationsbezogener Parameter wie z. B. Brandschweregraden. Zudem zeigt die Arbeit das große Potenzial zur genaueren Überwachung und Kartierung von sich schnell entwickelnden Umweltprozessen, das sich aus einer Sensorfusion ergibt.
    Language: English
    Type: info:eu-repo/semantics/doctoralThesis
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  • 16
    Publication Date: 2023-01-10
    Description: 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.
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  • 17
    Publication Date: 2023-01-13
    Description: 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.
    Language: English
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  • 18
    Publication Date: 2023-01-16
    Description: This data set includes overviews depicting the surface evolution (time-lapse photography, topography analysis, digital image correlation [DIC] analysis), as well as and progressive physical cross-section analysis of 18 laboratory experiments (analogue models) testing the influence of rheologically weak layers (i.e. layers with [a component of] viscous behaviour) and basal fault kinematics on deformation in the weak layer’s overburden. This model set-up was inspired by the geological situation in the Swiss Alpine Foreland. All experiments were performed at the Tectonic Modelling Laboratory of the University of Bern (UB). Detailed descriptions of the model set-up preparation and results, as well as the monitoring techniques can be found in Zwaan et al. (in review).
    Language: English
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  • 19
    Publication Date: 2022-12-05
    Description: The EUREF Permanent GNSS Network (EPN) provides a unique atmospheric dataset over Europe in the form of Zenith Total Delay (ZTD) time series. These ZTD time series are estimated independently by different analysis centers, but a combined solution is also provided. Previous studies showed that changes in the processing strategy do not affect trends and seasonal amplitudes. However, its effect on the temporal and spatial variations of the stochastic component of ZTD time series has not yet been investigated. This study analyses the temporal and spatial correlations of the ZTD residuals obtained from four different datasets: one solution provided by ASI (Agenzia Spaziale Italiana Centro di Geodesia Spaziale, Italy), two solutions provided by GOP (Geodetic Observatory Pecny, Czech Republic), and one combined solution resulting from the EPN’s second reprocessing campaign. We find that the ZTD residuals obtained from the three individual solutions can be modeled using a first-order autoregressive stochastic process, which is less significant and must be completed by an additional white noise process in the combined solution. Although the combination procedure changes the temporal correlation in the ZTD residuals, it neither affects its spatial correlation structure nor its time-variability, for which an annual modulation is observed for stations up to 1,000 km apart. The main spatial patterns in the ZTD residuals also remain identical. Finally, we compare two GOP solutions, one of which only differs in the modeling of non-tidal atmospheric loading at the observation level, and conclude that its modeling has a negligible effect on ZTD values.
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  • 20
    Publication Date: 2023-01-18
    Language: English
    Type: info:eu-repo/semantics/lecture
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  • 21
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    Publication Date: 2023-01-18
    Language: English
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  • 22
    Publication Date: 2023-01-18
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  • 23
    Publication Date: 2023-01-18
    Description: 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.
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  • 24
    Publication Date: 2023-01-18
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  • 25
    Publication Date: 2023-01-18
    Description: 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.
    Language: English
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  • 26
    Publication Date: 2023-01-23
    Description: 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.
    Language: English
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  • 27
    Publication Date: 2023-01-23
    Description: 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.
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  • 28
    Publication Date: 2023-01-23
    Language: English
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  • 29
    Publication Date: 2023-01-23
    Description: 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
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  • 30
    Publication Date: 2023-01-23
    Description: 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.
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  • 31
    Publication Date: 2023-01-27
    Description: 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.
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  • 32
    Publication Date: 2023-01-27
    Description: 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
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  • 33
    Publication Date: 2023-01-27
    Description: 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.
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  • 34
    Publication Date: 2022-11-14
    Description: The Pan-African belts of Malawi contain a largely unexplored endowment of gem bearing pegmatites. We present U–Pb in zircon (LA-ICPMS) and Rb–Sr mineral isochron geochronological and isotope data from pegmatites across Malawi. The pegmatites contain tourmaline, beryl, aquamarine, zircon, amethyst and sunstone as gemstone species. Two zircon bearing pegmatites in southern Malawi intruded early in the Pan-African orogenic cycle at 719 ± 5 Ma and 729 ± 4 Ma and are associated with the emplacement of alkaline rocks that formed during an intra-continental rifting episode in the eastern part of former Rodinia. One further zircon pegmatite containing inherited zircon of a similar age (746 ± 44 Ma) was emplaced at 598 ± 15 Ma, after the assembly of Western and Eastern Gondwana and the formation of the East African Orogen (EAO). The majority of the analysed pegmatites, however, are significantly younger. The ∼550 Ma pegmatites were emplaced during the Kuunga Orogeny, correlating with the collision of northern and southern Gondwana cratonic entities. During a prolonged post-collisional period, possibly related to crustal collapse and extension, further gem-mineralised pegmatites formed at ∼520 ± 6 Ma and ∼500–485 Ma. The youngest pegmatite intruded in the southern Malawian Ntcheu area in the Middle Ordovician at ∼460 Ma. A large spread in 87Sr/86Sr initial isotopic ratios between 0.70556 and 0.79018 suggests a variety of magma sources for the Kuunga-related pegmatites with a variably strong crustal affinity.
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  • 35
    Publication Date: 2022-11-14
    Description: Fault zones often serve as the major fluid pathways in a variety of geo-energy systems, such as deep geothermal systems. However, injection-induced instability of faults can sometimes lead to large-magnitude earthquakes. Cyclic injection has thus been proposed as an alternative injection protocol to better manage and mitigate the associated seismic risks. The risks of injection-induced seismicity depend primarily on the extent and magnitude of the fluid pressure perturbation. When fluid is injected into a fault zone, the local fault permeability will be enhanced, which in turn promotes the migration of fluid along the fault. This nonlinear process is further complicated during cyclic injection via alternating the injection pressure. In this study, both numerical and analytical modeling are conducted to investigate cyclic fluid injection into a fault zone with pressure sensitive permeability, in which the local fault permeability changes as a function of the local effective stress. The match with laboratory-scale experimental and field-scale analytical results of cyclic fluid injection verifies the accuracy of the numerical model. The parametric study reveals that the injection pressure attenuation, quantified by the amplitude ratio and phase shift, is enhanced by a lower initial fault permeability, a smaller stress sensitivity coefficient, and a shorter period of pressure cycle (i.e. a higher frequency). Besides, the amplitude of the pressure cycle has a negligible effect on the injection pressure attenuation. We also discuss the implications of our results for the less amenable far-field seismic hazard and post shut-in seismicity.
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  • 36
    Publication Date: 2022-12-14
    Description: Ilmenite and olivine megacrysts from the 89 Ma Monastery kimberlite (Kaapvaal Craton, South Africa) captured abundant and large melt inclusions containing quenched Si-Mg-rich melt, calcite, spinel, perovskite, phlogopite, and serpentine. Textural observations and 3D X-ray tomography of ilmenite and olivine megacrysts show melt inclusion shapes, sizes and distribution patterns indicative of melt capture during primary crystal growth near the base of the subcontinental lithospheric mantle (SCLM). Patterns supporting secondary melt injection along fractures or veins, such as planar arrays of melt inclusions, are absent. Melt inclusions in olivine, in some examples reaching the dimension of centimetres, likely were captured in skeletal voids forming in fast growing, up to decimetre-sized olivine megacrysts. These large melt inclusions commonly decrepitated, forming apophyses, radial fractures, and veins, along which residual volatile- and Si-Mg-rich melt was extracted. We attribute the decrepitation of melt inclusions in olivine to the rapidly increasing difference between the melt pressure in the inclusions, captured at mantle depth, and the decreasing confining stress to which the host olivines were exposed during magma ascent and after emplacement. In ilmenite, melt inclusions up to ∼ 6 mm in diameter remained commonly intact during the kimberlite ascent from its mantle source to the shallow crust. The quenched silicate melt in olivine- and ilmenite-hosted melt inclusions, in some places preserved as unaltered hydrous and CO3-bearing glass, shows systematic major element compositional variations that suggest that this melt formed by similar fractionation and depletion processes, irrespective of the hosting megacryst phase. Apparent modal variations in quenched silicate melt, calcite, and oxide contents suggest that the melt batches captured as inclusions in ilmenite and olivine either record different evolution stages in the megacryst magma, or document compositional heterogeneities in this magma at the time of megacryst growth.
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  • 37
    Publication Date: 2023-08-02
    Description: The study of Electro Magnetic Ion Cyclotron (EMIC) wave-induced electron precipitation has a legacy in early work suggesting EMIC waves could precipitate relativistic electrons. As such, EMIC waves represent a significant loss process for the Outer Radiation Belt, and deposit high energy electron precipitation flux deep into the atmosphere. Here we present an analysis of an example of EMIC-induced electron precipitation observed by two satellites in Low Earth Orbit, combined with EMIC wave signatures in ground-based magnetometers in Finland, and Antarctica. Electron precipitation spectral information is provided by satellite data which considers the energy range of scattered electrons during the potential EMIC wave event. We investigate the high energy resolution DEMETER IDP electron measurements in the 80 keV - 2 MeV range, when the detector was looking into the bounce-loss-cone, i.e., flying over the North Atlantic region. In order to assess the effect of potential proton precipitation contamination of the IDP detector we use nearby POES proton flux measurements, compensating for the IDP protective aluminium foil through a calculation of the attenuation of the proton spectrum using the integrated MULASSIS transport code. Our results are considered in the context of recent work indicating a wide energy range of non-relativistic electron precipitation is present in EMIC-induced precipitation in addition to the relativistic energy electrons suggested from the original theoretical suggestions. Our confirmation of non-relativistic energy ranges in EMIC-induced precipitation events supports the atmospheric chemical modelling analysis undertaken recently which showed that EMIC-induced precipitation is capable of causing notable composition changes.
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  • 38
    Publication Date: 2023-08-02
    Description: In Germany, climate resilient tree species are increasingly used in the process of forest conversion towards climate-change adapted stands. However, information on the impact of this conversion on groundwater resources is scarce. To fill this gap, the joint project “Effects of climate-adapted tree species selection on groundwater recharge” of the Federal Institute for Geosciences and Natural Resources (BGR) and the Northwest German Forest Research Institute (NW-FVA), funded by the Forest Climate Fund (WKF), aims at better understanding processes of groundwater recharge at six forest sites. The study sites comprise monoculture forest stands of European beech, Norway spruce, Douglas fir, Scots pine, red oak and pedunculate oak. To assess groundwater recharge rates, we performed D2O-tracer experiments on four sites since December 2022. At each site one plot of 4 m² was irrigated with 5 mm of D2O-labelled water (δ2H: 110 000 – 140 000 ‰). We will present the results of the tracer peak displacement until spring 2023 for each plot together with groundwater recharge estimates based on soil gravimetric water content and bulk dry density data. In addition, at two sites (red oak and Scots pine), these results will be compared to natural seasonal signals of stable isotopes in the soil water. Preliminary results of the red oak lowland forest site show that during summer 2022 seasonal signals reached down to 4 m depth and that gravimetric water contents dropped below 4 % for the entire mineral soil profile reaching down to the capillary fringe at 6.50 m.
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  • 39
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    In:  XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG)
    Publication Date: 2023-08-02
    Description: The flow dependent impact of multiple sources of uncertainty on convective precipitation is investigated in a consolidated way using the operational convection permitting ICON-D2 model in ensemble mode. Two model uncertainties -- microphysics (MP) and planetary boundary layer (PBL) turbulence --are considered in the presence of initial and lateral boundary condition uncertainties. The case studies are stratified based on the strength of synoptic control on convection. We found that model uncertainties act on different processes and spatiotemporal scales. MP uncertainty hardly has an impact on precipitation amounts at small spatiotemporal scales but influences daily accumulations. In contrast, the physically-based stochastic perturbations (PSP) in the PBL directly impact the diurnal cycle of precipitation. MP uncertainty only weakly impacts scales of O(100km), whereas the uncertainty in PBL significantly changes the spatial distribution at smaller scales at certain times. Those impacts on amounts and spatial distributions are more sensitive during weak synoptic control. The combination of various uncertainties adds further variability to forecast distributions and is potentially beneficial for improving the underdispersion of forecast spread of precipitation, especially during weak synoptic control.
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  • 40
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    In:  XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG)
    Publication Date: 2023-08-02
    Description: Recent years have seen an increase in the use of non-contact methods of river discharge estimation, which calls for the measurement of surface velocity in the top portion of the cross-section utilizing non-contact doppler radar sensors like Handheld or Mounted radars. Given the constrained and probabilistic character of the flow, these radars can be utilized to predict discharge based on the entropy theory. Additionally, a river section can be utilized to measure surface velocity at several predetermined verticals using the traditional area-velocity approach. One of the major prerequisites for the estimation of discharge through non-contact techniques is the characterization of the nature of the surface velocity profile at the section. The problem arises when the flow experiences large turbulence due to sidewall effects and other characteristics of the channel, especially in narrow mountainous channels. This study compares different velocity profiles for the measured surface velocity at several predefined verticals at two cross-sections of Bhagirathi and Ganga, two significant Himalayan rivers having widths of 30m and 60m respectively. . Three velocity profiles i.e. Elliptic, Parabolic, and Polynomial profiles obtained through the curve-fitting technique were compared based on error distribution and uncertainty analysis using Forecast Range Error Estimate method. Further, to determine which profile would be optimal for the selected segments, the measured mean velocity of current-meter was compared to the estimated mean velocity for each profile. The study offers a straightforward method for choosing the ideal surface velocity profile for a river by just measuring the surface velocity at predetermined verticals.
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  • 41
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    In:  XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG)
    Publication Date: 2023-08-02
    Description: The present study investigates the interannual variability of the tropical Indian Ocean (IO) based on the transfer routes of wave energy in a set of 61-yr hindcast experiments using a linear ocean model. To understand the basic feature of the IO dipole mode, this paper focuses on the 1994 pure positive event. Two sets of westward transfer episodes in the energy flux associated with Rossby waves (RWs) are identified along the equator during 1994. One set represents the same phase speed as the linear theory of equatorial RWs, while the other set is slightly slower than the theoretical phase speed. The first set originates from the reflection of equatorial Kelvin waves at the eastern boundary of the IO. On the other hand, the second set is found to be associated with off-equatorial RWs generated by southeasterly winds in the southeastern IO, which may account for the appearance of the slower group velocity. A combined empirical orthogonal function (EOF) analysis of energy-flux streamfunction and potential reveals the intense westward signals of energy flux are attributed to off-equatorial RWs associated with predominant wind input in the southeastern IO corresponding to the positive IO dipole event.
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  • 42
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    In:  XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG)
    Publication Date: 2023-08-02
    Description: Over the past years, with the rapid progress of Global Navigation Satellite System Interferometric Reflectometry (GNSS-IR) technique, near-shore geodetic GNSS receivers have been attempted to retrieve dynamic sea-level variation induced by storm surges and tsunamis. As the largest event since 1939, the 2023 M7.8 Turkiye earthquake not only caused terrifying building collapses on land but also generated observable tsunamis in the sea as recorded by coastal tide gauges. In this study, we thus try to verify the performance of GNSS-IR sea-level retrieval for tsunami monitoring based on GNSS data from IGS and TPGN(Turkish Permanent GNSS Network). Our preliminary findings show that, in spite of a continental strike-slip rupture, a tsunami with 30 cm wave height, following days of ocean resonance, is clearly seen by GNSS-IR, consistent with nearby tide gauge records. Furthermore, we also perform a finite source inversion to explore whether a submarine landslide contributes to the tsunami. Our work demonstrates the capability of GNSS-IR for detecting medium and small tsunamis accurately. In fact, such geodetic GNSS receivers have been now well-deployed for co-seismic displacement monitoring and fast earthquake source characterizing for tsunami early warning in many places in the world. If more receivers can be installed near-shore, without extra operational costs, such a network will extend our tsunami observation power and improve the robustness of the tsunami early warning system.
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  • 43
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    In:  XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG)
    Publication Date: 2023-08-02
    Description: On 30 October 2020 at 11:51 UT, a magnitude 7.0 earthquake occurred in the Dodecanese sea (37.84°N, 26.81°E, 10 km depth), that generated a tsunami with an observed run-up of more than 1 meter on the Turkish coasts. Both the earthquake and the tsunami produced acoustic and gravity waves that propagated upward, triggering co-seismic and co-tsunamic ionospheric disturbances. This paper presents a multi-instrumental study of the ionospheric impact of the earthquake and related tsunami based on ionosonde data, ground-based and Swarm-based GNSS receivers, and Jason3/DORIS [L1] receivers in the Mediterranean region. Our study focuses on the Total Electron Content derived from the European GNSS network, Swarm, and Jason3, to describe the propagation of Medium Scale Travelling Ionospheric Disturbances (MSTIDs), possibly related to gravity waves triggered by the earthquake and tsunami. We use simultaneous vertical ionosonde soundings to study the interactions between the upper and lower atmosphere. The results of this study provide a detailed picture of the Litosphere-Atmosphere-Ionosphere coupling in the scarcely investigated area that is the Mediterranean region.
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  • 44
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    In:  XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG)
    Publication Date: 2023-08-02
    Description: The tropical Angolan upwelling system (tAUS) is a highly productive ecosystem with a distinct seasonal variability with productivity peaking in austral winter. The tAUS is connected to equatorial dynamics via the propagation of equatorial and coastal trapped waves (CTWs). We use hydrographic, ocean turbulence and satellite data to investigate the role of CTWs in controlling the seasonal cycle of productivity in the tAUS. During austral winter associated with the passage of an upwelling CTW, the nitracline is displaced upward by about 50 m. Through this vertical advection nitrate-rich waters passes onto the shelf. Due to the elevated mixing rates on the shelf, this movement of the nitracline results an increased vertical nitrate flux into the ocean mixed layer. Our analysis further shows that interannual variability in the strength of the austral winter net primary production correlates with the amplitude of the seal level anomaly signal of the corresponding upwelling CTW. The signal of sea level depression leads the maximum productivity signal by about 40 days. It is suggested that this time lag arises, among other factors, from the vertical structure of the CTWs arriving in the tAUS. While the sea level anomaly is dominated by the faster low-baroclinic mode CTWs, the displacement of the nitracline is mainly influenced by the slower high-baroclinic mode CTWs that arrive later in the tAUS. Our results highlight the crucial role CTWs play for the productivity in the tAUS. The strong connection between equatorial dynamics and productivity further introduces a possibility for predicting interannual variability.
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  • 45
    Publication Date: 2023-08-02
    Description: The recent global MHD simulation code (REPPU code by Tanaka [2015]) successfully reproduces even observed phenomena such as the auroral breakup of the substorm. We judge that the simulation code correctly reproduces the physical processes of the magnetosphere and ionosphere from the fact that the phenomenon is reproduced realistically. REPPU code employs several empirical parameters expressing the non-MHD mechanisms. We tried to determine the optimal values of the parameters by using the data assimilation technique. For this purpose, we improve the REPPU code to include both the effect of the inclined rotation axis of the Earth and the effect of the discrepancy between the rotational axis and the magnetic axis. Next, we apply the data assimilation technique to determine the ionospheric conductivity distribution which is given as empirical parameters in the original REPPU code. For this purpose, we use the ionospheric electric potential determined by SuperDARN and AE indices. We employed the ensemble variational method as the assimilation technique to obtain the optimal values of the parameters. As a result, we obtained that the ionospheric conductivities are enhanced compared with the empirical results. At the same time, modification of the ionospheric conductivity does not change significantly the magnetosphere. The simulation data become the “reanalysis data” of the space weather which is useful for space weather research. Our future goal is to provide a database of the reanalysis data for space weather.
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  • 46
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    In:  XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG)
    Publication Date: 2023-08-02
    Description: Climatology, also named the "Climate Normal" by World Meteorological Organization (WMO), is critical for characterizing historical or near-future weather and climate states, and is usually calculated for a uniform 30-year period according to the WMO definitions. However, in addition to external forcing changes, climatology can be impacted by internal climate variabilities on multi-decadal and longer time scales. Here we introduce a simple sampling model and conduct three equilibrium climate sensitivity experiments using a Global Climate Model EC-Earth to quantify the potential uncertainties in estimating equilibrium climate change. We take into account the effect of multi-centennial variability in the climate system, which has been identified in paleo-climate proxy records and long climate model simulations. For the time series that contain multi-centennial oscillation, the estimate of climate change refers to the difference between two equilibrium climate states that may have significant uncertainty due to random selection of the phase location of the sampling. Our exercises with EC-Earth experiments show that such uncertainties are significant at high latitudes where low-frequency oscillations dominate. The accuracy of the estimated climate state at mid-to-high latitudes in the Northern Hemisphere is mainly impacted by the multi-centennial oscillation, while the uncertainty in mid-to-high Southern Hemisphere is affected by the oscillation on multi-centennial to millennial time scales. We show that applying quasi-periodic sampling in calculating the equilibrium climate state can significantly reduce such uncertainties. This work reminds us that the potential uncertainties induced by multi-centennial climate variability cannot be ignored when the length of sampling data is limited.
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  • 47
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    In:  XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG)
    Publication Date: 2023-08-02
    Description: The study examines the interannual relationship between the variability of sea ice extent in the Indian Ocean sector (20–90oE) and Indian summer monsoon rainfall under the influence of Mascarene High. Sea ice extent during April-May-June (AMJ) appears to have a significant correlation with the summer monsoon rainfall over the Peninsular India region during June-July-August-September from 1979 to 2013. We utilized reanalysis, satellite, and in-situ observation data from 1979 to 2013. The empirical orthogonal function (EOF) and correlation analysis show that the first and third modes of principal component (PC1 and PC3) of SIE in the Indian Ocean sector during April-May-June (AMJ) are significantly correlated with the second mode of principal component (PC2) of Indian summer monsoon rainfall. The reanalysis data revealed that the changes in the SIE in the Indian Ocean sector excite meridional wave train responses along the Indian Ocean for both principal component modes. Positive (negative) SIE anomalies based on first and third EOFs (EOF1 and EOF3) contribute to the strengthening (weakening) of the Polar, Ferrel, and Hadley cells, inducing stronger (weaker) convective activity over the Indian latitudes. The weak (strong) convective activity over the Indian region leads to less (more) rainfall over the region during low (high) sea ice phase years. Furthermore, a weaker (stronger) polar jet during the low (high) sea ice phase is also noted.
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  • 48
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    In:  XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG)
    Publication Date: 2023-08-02
    Description: Frequency of extreme rainfalls and snowfalls has been increasing these years, and those events severely affect human lives and properties. It has been considered that tropical ocean and atmosphere variability as well as the warming climate, remotely influences mid-latitude extreme weather/climate, while the mid-latitude ocean is passive to atmospheric variability. Recent high-resolution ocean/atmospheric data analyses, however, have revealed that mid-latitude ocean also influences atmospheric circulations and their variability. Rediscovering strong warm current and associated strong ocean frontal zones as “climate hotspot”, we have elucidated mechanisms of ocean-atmosphere interactions. The research progress has prompted a new crucial task: application of such new knowledge to predictions of extreme rainfalls/snowfalls and climate variability. For the new task, in the five-year research project called “Climatic Hotspot2” from 2019, we have conducted studies to further our understandings of mid-latitude ocean-atmosphere interaction processes. In the project, several observation campaigns and also oceanic and atmospheric high-resolution numerical modeling studies have been conducted. Those studies have revealed crucial influence of ocean currents and oceanic structures on climate extreme events. In this presentation, we introduce results of the projects, including predictability of the Kuroshio Extension and Gulf Stream jet speeds and eddy activities around them. This presentation is co-authored with the Climatic Hotspot2 group.
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  • 49
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    In:  XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG)
    Publication Date: 2023-08-02
    Description: Direct observations of sunspots exist for the past four centuries while proxy based reconstructions exist for thousands of years. Over a significant fraction of the past century, records of sunspot tilt angles and areas have also been collected. These observations provide a means to understand the physics of long-term solar variability by discriminating between various models of the solar cycle. In this talk, I shall discuss how the synergy of solar surface flux transport modelling, dynamo modelling and solar activity observations have led us to the conclusion that the primary driver for decadal-scale variability in the solar cycle is imbibed in the Babcock-Leighton mechanism for poloidal field generation which is governed by the emergence of tilted bipolar sunspot pairs and their subsequent evolution driven by flux transport processes. I shall also highlight what this emergent understanding implies for solar cycle 25 forecasts.
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  • 50
    Publication Date: 2023-08-02
    Description: Upper-ocean fronts are dynamically active features of the global ocean that have significant implications for air-sea interactions, vertical mass and heat transfers, stratification and phytoplankton production and export. Their small dimensions and short duration have limited our capacity of observing, modelling and understanding fully these processes and their impact. To address this challenge, five Saildrones - which are uncrewed platforms instrumented to measure the air-sea interface – were deployed during the EUREC4A-OA/ATOMIC field experiment in the Northwest Tropical Atlantic in winter 2020. This region is strongly affected by the outflow of the Amazon River, leading to the generation of fine-scale horizontal thermohaline gradients with the stirring of this freshwater input by large anticyclonic eddies. Very intense gradients, including at the smaller spatial scales, were measured. The coherence of temperature and salinity fronts was estimated by a wavelet transform analysis which revealed large-scale density fronts are primarily controlled by salinity but with increasing temperature-salinity coherence at the small scales range of the spectrum (O (0.1 km)) for strong gradients whereas they are poorly correlated for weaker fronts. Our study shows that processes such as the mixed layer depth, the diurnal cycle, and air-sea exchanges are strongly affected by these small-scale frontal regimes. The parallel and quasi synchronous tracks of a 4-Saildrone formation provide a detailed picture of the upper ocean vorticity, divergence, and strain from their ADCP current measurements. Overall the methodology developed could be extended on other datasets to assess the phenomenology of fine-scale structures in other dynamical regions.
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  • 51
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    In:  XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG)
    Publication Date: 2023-08-02
    Description: Localized disturbances within the altitude range of lower ionospheric D-region, related to precipitation of energetic electrons from radiation belts, causes perturbations of VLF signal propagation parameters during nocturnal conditions within Earth-ionosphere waveguide. Based upon Very Low Frequency (VLF) signal perturbations through the remote sensing technique, indirect conclusions regarding some of the features of such Localized Ionospheric Enhancements (LIEs) can be obtained. In this work, several dozens of Lightning-induced Electron Precipitation (LEP) type VLF signal perturbations were analyzed as case studies, with the goal to get insight into similarities and differences between related LIEs formed in mid-latitude lower ionosphere over the west and central European region, using VLF recordings from two ground-based receiving systems, stationed at the Institute of Physics Belgrade (Serbia). Inspected cases included LEP events from period 2003 – 2011, with notable amplitude and phase changes compared to unperturbed ionospheric conditions. As input data for numerical simulations, amplitude and phase perturbations monitored on signals emitted from major European and American transmitters, were used. Subionospheric VLF signal propagation was modeled using the LWPCv21 program routine, relying on Wait's theory and by employing parameters sharpness and reflection edge height, for nighttime Great Circle Path (GCP) sections. Obtained electron density height profile changes along observed GCPs according to Belgrade VLF data, place the size as main common feature of considered LIEs, as less than: 1000 km in length and 500 km in width, with significant differences regarding their internal structure and position.
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  • 52
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    In:  XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG)
    Publication Date: 2023-08-02
    Description: The dynamic behavior of saline water intrusion along coastal areas affects groundwater resources adversely. For the assessment of such problems, the present study deals with time-lapse electrical resistivity monitoring. The study observed changes in subsurface resistivity with time constraints to locate the saline zones in aquifers. Resistivity data was collected using Dipole-Dipole and Wenner-Schlumberger arrays for getting optimum resolution. The damping factor was chosen for the time-lapse inversion algorithm according to the noise present in field data. 2D images of subsurface conditions were interpreted according to the percentage variation in resistivity values. It was observed that saline clay layers were present in multiple depths ~12m and 39m below ground level. Further, different attributes can be retrieved from the time-lapse inversion results as desaturation percentage and resistivity ratio, which can give a brief idea about the movement of contaminants inside the subsurface.
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  • 53
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    In:  XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG)
    Publication Date: 2023-08-02
    Description: In this study, we re-examine the use of an existing theoretical model for predicting the time-variable large-scale circulation along contours of constant ambient potential vorticity, given by f/H, in the Nordic Seas and Arctic Ocean. The theoretical model is an integral relation derived from the linear depth-averaged shallow water equations, and assumes that the circulation is driven by surface stresses and regulated by bottom drag. By applying this simplified model to a high-resolution numerical simulation, we assess its ability to accurately predict the circulation. Improvements from earlier examinations include better parametrization of stresses in ice-covered regions and higher resolution in the numerical simulation. Our results show that the linear model agrees well with the complex model. This indicates that much of the variability in the large-scale circulation can be explained by linear processes. However, we find that the performance of the linear model depends on the direction of the circulation, with the linear model overestimating anti-cyclonic circulation. This suggests that additional processes, not captured in the linear model, play a crucial role in anti-cyclonic circulation.
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  • 54
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    In:  XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG)
    Publication Date: 2023-08-02
    Description: In this study, we demonstrate that the enhanced storm track activity in the North Pacific midlatitudes during boreal winter over the past four decades was correlated with subtropical warming which strengthened midlatitude meridional temperature gradient. On the contrary, Arctic warming reduced the near-surface temperature gradient and had negative correlation with midlatitude storm track activity. The close relationship between temperature gradient and synoptic eddy activity is dynamically fundamental and can be seen in both long-term trends and the interannual variation. The observed trends in warming sea surface temperature (SST) in the subtropical North Pacific, ascending motion over the subtropical western North Pacific and anticyclonic circulation over the central and western North Pacific suggests a positive feedback between warming SST and atmospheric circulation. Numerical experiments further revealed that SST warming in the subtropical North Pacific and in the Indian Ocean could drive subtropical tropospheric warming and anticyclonic circulation in the North Pacific, as well as the strengthening of the North Pacific midlatitude storm track activity. The results suggest tropical and subtropical influence on North Pacific midlatitude winter weather.
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  • 55
    Publication Date: 2023-08-02
    Description: The system of oceanic flows constituting the Atlantic Meridional Overturning Circulation (AMOC) moves heat and other properties to the subpolar North Atlantic, controlling regional climate, weather, sea levels, and ecosystems. Climate models suggest a potential AMOC slowdown towards the end of the 21〈sup〉st〈/sup〉 century due to anthropogenic forcing, which would accelerate coastal sea level rise along the western boundary and dramatically increase coastal flood risk. While the slowdown has not been observed to date, we show here that the AMOC-induced intrinsic changes in gyre-scale heat content, superimposed on the global mean sea level rise, are already influencing the frequency of floods along the United States southeastern seaboard. For the South Atlantic Bight and Gulf of Mexico coasts, using observations and an ocean state estimate, we have established a strong link between coastal sea level, the associated flood frequency, and gyre-scale dynamic sea level and oceanic heat content variability, which are largely controlled by AMOC-driven ocean heat convergence. We find that ocean heat convergence, being the primary driver for interannual sea level changes in the subtropical North Atlantic, has led to an exceptional gyre-scale warming and associated dynamic sea level rise since 2010, accounting for 30-50% of flood days in 2015-2020. The results of this study highlight the importance of accounting for natural, large-scale sea level variability in order to improve coastal sea level projections and to better assess coastal flood risk.
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  • 56
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    In:  XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG)
    Publication Date: 2023-08-02
    Description: The depletion of plasma in the nighttime F region ionosphere is called the mid-latitude ionospheric trough (MIT). The objective of this study is to identify and describe the mid-latitude ionospheric trough by using new satellite data and expanding our understanding of the MIT phenomenon. To evaluate the MIT, we used electron density in-situ data derived from GRACE satellite K-Band Ranging system (KBR) measurements. The trough was examined using data collected between 2002 and 2015, including high and low solar activity periods. We analyze the characteristics of the mid-latitude ionospheric trough (MIT) in both the Northern and Southern Hemispheres. The MIT is characterized by its trough’s minimum position, width, depth, and probability. We investigated how MIT parameters were affected by the magnetic local time, geographic distribution, seasons, and solar and geomagnetic activity conditions, including solar wind plasma speed, interplanetary magnetic field components, and high-resolution geomagnetic indices SYM-H and Hp30. In this study, we demonstrate the elliptical distribution of the mean location of the trough minimum over three seasons for the Northern and Southern hemispheres and the MIT parameter dependency on high-resolution geomagnetic indices. Our findings confirm and extend earlier research on MIT. The obtained dependencies related to MIT climatology and occurrence probability can be used to validate existing MIT models and create new MIT models since it has not yet been represented in commonly used 3D electron density models, such as IRI, NeQuick, NEDM2020, etc. The integration of an MIT model may improve the performance of the 3D electron density models.
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  • 57
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    In:  XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG)
    Publication Date: 2023-08-02
    Description: The second national pollution source survey showed that agricultural non-point source pollution (ANP) has become one of the main causes of water environment deterioration in Guangdong Province. It is important to clarify the ANP status in the province for the prevention and control of water pollution and the construction of rural revitalization. The improved export coefficient method was used to analyze the annual ANP loads and their spatial and temporal variation characteristics in Guangdong Province from 2009 to 2019. The seasonal and monthly pollution loads of ANP were also evaluated with consideration of monthly differences in fertilizer application, precipitation, livestock, and aquaculture. The impact of ANP on the water environment was evaluated by the unit area load coefficient method, and the main sources of ANP were explored. The results indicate that (i) from 2009 to 2019, the total nitrogen load in Guangdong province showed a decreasing trend and the total phosphorus load showed a rising trend with spring and summer being the peak seasons of pollution emissions in a year; (ii) The total nitrogen load trended decreasing in 76.2% of the cities and the total phosphorus load trended increasing in 61.9% of the cities; (iii) in general, the environmental damage caused by agricultural nitrogen and phosphorus loads in western Guangdong was more serious than that in Pearl River Delta, northern and eastern Guangdong; and (iv)the contribution rate of pollution source to nitrogen and phosphorus pollution loads from high to low is livestock and poultry breeding, planting and aquaculture.
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  • 58
    Publication Date: 2023-08-02
    Description: De Santis et al. (EPSL 2017) detected that for the first time in Swarm satellite data some magnetic field anomalies associated with the 2015 Nepal M7.8 earthquake, with similar S-shapes for the cumulative number of satellite anomalies and earthquakes, providing an empirical proof on the lithospheric origin of the anomalies. Following the same approach, De Santis et al. (Atmosph. 2019) obtained other promising results for 12 earthquakes in the range M6.1-8.3, in the framework of the ESA funded SAFE (SwArm For Earthquake study) Project. Then, almost five years of Swarm magnetic field and electron density data were analysed with a Superposed Epoch and Space approach finding a robust correlation with major worldwide M5.5+ earthquakes (De Santis et al. Sc.Rep. 2019). The work also confirmed the Rikitake (1987) law, initially proposed for ground data: the larger the magnitude of the impending earthquake, the longer the precursory time of anomaly occurrences. An analogous analysis was also applied in the framework of the ASI funded Limadou-Science Project to the Chinese Seismo-Electromagnetic satellite (CSES) electron density providing similar results (De Santis et al. N.Cim. 2021). Marchetti et al. (Rem.Sens. 2022) confirmed the same result over a longer time series , i.e. 8 years, of Swarm satellite data. Furthermore, we demonstrated in several case studies (e.g. Marchetti et al. JAES 2019, Akhoondzadeh et al. Adv.S.R. 2019; De Santis et al. Fr.E.Sc. 2020) that the integration of CSES and Swarm data with other measurements from ground an atmosphere reveals a chain of processes before many mainshocks.
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  • 59
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    In:  XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG)
    Publication Date: 2023-08-02
    Description: We present 10-day water mass solutions estimated from both GRACE and GRACE-FO KBR Range (KBRR) residuals for continental hydrology using GINS software developed by the CNES/GRGS group. The inter-satellite velocity residuals have been converted into along-track differences of potential using the energy balance approach. Maps of equivalent water height are obtained by inversion of these potential differences onto juxtaposed surface elements over the region of interest, or better, time coefficients of designed orthogonal Slepian functions. This latter band-limited representation offers the advantage of reducing drastically the number of parameters to be fitted. Shannon number of 60 for the regional Slepian representation is usually considered for GRACE-type data for basins of arbitrary shapes. The regional solutions are validated by comparison with series of existing Level-2 solutions produced by (official) centers once the contribution of the missing long-wavelength part of the time-varying field, i.e. low degree harmonic coefficients such as C〈sub〉20〈/sub〉, is simply added for completion. The patterns shown in the regional solutions reveal strong seasonal variations of water mass in the large tropical basins, e.g. Amazon and Congo, as well as important trends corresponding to regional droughts and continuous melting of the ice sheets that contributes to sea level rise.
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  • 60
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    In:  XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG)
    Publication Date: 2023-08-02
    Description: Stratospheric ozone levels, temperature trends and their evolution in time have been the subject of global concern and scientific research already since the mid 1970’s. The evolution of changes and trends in the vertical distribution of ozone and temperature as depicted in Chemistry-Climate Models simulations (CCMI) is examined. The solar signature in stratospheric variability is assessed, as well as the contribution of other natural variability forcings (such as ENSO, QBO and volcanic activity). Ozone and temperature trends are calculated for the periods before and after the year 2000 (pre-2000 and post-2000). Results are compared to trends derived from earlier model studies as well as to ozone trends from satellite records updated in the LOTUS SPARC project, over the same periods and latitude belts characteristic to the ozone variability, by applying the same statistical methods in accordance with the regression analysis and tools presented in the LOTUS Project.
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  • 61
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    In:  XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG)
    Publication Date: 2023-08-02
    Description: Coastal submarine canyons are potential sites of enhanced turbulent mixing that could make them productive fishing grounds. Recent studies suggest the crucial role of diurnal coastal trapped waves (CTWs) in inducing significant turbulent mixing in coastal submarine canyons poleward of 30º, where the diurnal tide is subinertial. However, the detailed physical processes responsible for the generation and dissipation of CTWs in such submarine canyons remain to be investigated. In this study, to investigate the turbulent mixing processes associated with diurnal CTWs in submarine canyons, we conduct high-resolution three-dimensional numerical experiments focusing on the northern end of the Suruga Trough, Japan. It is found that CTWs generated by diurnal (subinertial) tidal currents over the nearby Izu-Ogasawara Ridge propagate anticlockwise with the slope of the Suruga Trough on the right. Furthermore, the bottom-intensified flow associated with the diurnal CTWs interacts with the rough seafloor topography to excite internal lee waves that propagate upward while creating mixing hotspots that extend high above the seafloor. We also find that the baroclinic energy flux based on a simple barotropic-baroclinic decomposition severely underestimates the wave energy flux in areas of high CTW activity. These results indicate that the presence of CTWs is a key factor in elucidating the dissipation/mixing processes in submarine canyons. In the presentation, we will also compare the results of the above numerical experiments with those of direct microstructure measurements conducted in the Suruga Trough in November 2021.
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  • 62
    Publication Date: 2023-08-02
    Description: Local evaporation in the Arctic is likely to increase with sea-ice retreat in the context of climate change. In parallel, the transport of moisture from the North Atlantic may also increase, especially in cases of weak polar vortex, associated to blocking over the Norwegian Sea and fast vapor transport into the Arctic. In order to evaluate the contribution of different sources to the moisture budget in the Arctic, a tool is needed to track the transport of vapor in the region. Here, we combine in-situ measurements of vapor isotope composition to analysis of back- trajectories, to reconstruct the pathway of vapor transport in different synoptic situations during two cruises North of Svalbard in 2018 and 2019. During the hot summer of 2018 in Europe, high dD values are observed in the Arctic. These high values could result from intense evaporation during the heat wave followed by quick transport into the Arctic. Indeed, back-trajectories indicate northern Europe as a dominant contributor to the moisture sampled during this period. During summer 2019, we observe wide oscillations of dD values depending on the moisture origin. An atmospheric river is sampled on the 29th of August 2019, that shows that Atlantic (southerly) air is characterized by high humidity and high dD values, opposite to Arctic (northerly) air. The secondary parameter d-excess varies in opposition to dD. This study highlights the potential of isotopes for identifying moisture sources around the Arctic.
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  • 63
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    In:  XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG)
    Publication Date: 2023-08-02
    Description: Modeling tropospheric delay is critical to achieving high-precision data analysis of space geodetic techniques, such as Global Navigation Satellite System (GNSS), Very Long Baseline Interferometry (VLBI), and satellite altimetry. Numerical Weather Models (NWMs) are an important source to provide both empirical tropospheric delay models and real-time corrections, and are widely used as a priori values, external constraints, and precise correction values. The uncertainty of NWM-derived empirical models is around 3 to 4 cm, and that of reprocessed and real-time products is around 1 to 2 cm. However, this uncertainty is mostly derived using long-term data on a global scale, and the geography- and season-related uncertainty variations have not been revealed thoroughly. In this study, we investigate the uncertainty of NWM-derived tropospheric delay products using a huge amount of globally distributed GNSS stations (more than 10,000) over ten years, and focus on the geographical and seasonal distributions. We demonstrate that the uncertainty of NWM-derived tropospheric delays (1) have clear seasonal variations, that is, larger in the Summer season when the water vapor is more abundant and with rapid fluctuations, and (2) shows a strong dependence on the geography, which is also attributed to the water vapor distribution and variation differences. Our work could provide a reference for future research of exploiting NWM-derived tropospheric delays, especially in real-time GNSS positioning and navigation.
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  • 64
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    In:  XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG)
    Publication Date: 2023-08-02
    Description: With the advent of plate tectonics in the last century, our understanding of the geological evolution of the Earth system improved essentially. The internal deformation and evolution of tectonic plates remain however poorly understood. This holds in particular for the Central Mediterranean: The formerly much larger Adriatic plate is recently consumed in tectonically active belts spanning at its western margin from Sicily, over the Apennines to the Alps and at its eastern margin from the Hellenides, Dinarides towards the Alps. It has been shown that data acquired by dense, regional seismic networks like AlpArray provide crucial information on seismically active faults as well as on the structure and deformation of the lithosphere. The Adriatic Plate and in particular its eastern margin have however not been covered by a homogeneous seismic network yet. Here we report on the status of AdriaArray – a seismic experiment to cover the Adriatic Plate and its actively deforming margins by a dense broad-band seismic network. Within the AdriaArray region, currently about 990 permanent broad-band stations are operated by more than 40 institutions. In addition, 414 temporary stations from 24 mobile pools are deployed in the region achieving a coverage with an average station distance of 50 – 55 km. The experiment is based on intense cooperation between local network operators, mobile pool operators, field teams, and ORFEUS. Altogether, more than 50 institutions are participating in the AdriaArray experiment. We will report on the time schedule, participating institutions, mobile station pools, and maps of temporary station distribution.
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  • 65
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    In:  XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG)
    Publication Date: 2023-08-02
    Description: The term "space weather" summarizes phenomena in the solar system that originate from the sun and can affect modern technological infrastucture - including disturbances of navigation systems (e.g. GNSS), problems in power supply operation, as well as the loss of radio communication. The SWAP (Space Weather: The Austrian Platform) project deals with the diffusion of space weather information and expertise to potential users and the public. Funded as part of the Austrian Space Applications Programme (FFG), the project is carried out by a consortium of eight partners in space weather research and application. Our aims are to (1) create a network of national experts in the field, (2) establish a national space weather platform, and (3) plot a road map for future development in Austria. In this presentation, we will provide an overview on our progress in developing a national platform. A newly established website serves as a single point of entry into the topic of space weather in Austria. We use this platform as a launchpad to contact potential stakeholders and provide a resource of combined space weather expertise, with the intent to extend awareness of space weather events and their potential consequences. Using a space weather “atlas”, the website ties together the existing expertise with space weather topics. A direct line of contact to the relevant experts is provided in case of extreme events. We have identified various stakeholders including regional warning centres, power grid operators, groups relying on GPS and radio signals, and the press, among others.
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  • 66
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    In:  XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG)
    Publication Date: 2023-08-02
    Description: Extreme weather events caused by tropical and extratropical cyclones have destructive impacts on infrastructure, society, and environment. Forecasting extreme weather continues to present challenges. We consider solar wind coupling to the magnetosphere-ionosphere-atmosphere system, mediated by globally propagating aurorally excited atmospheric gravity waves, influencing the occurrence of severe weather. While these gravity waves reach the troposphere with attenuated amplitudes, they are subject to amplification when encountering opposing winds and vertical wind shears. They can release conditional symmetric instability [1] leading to slantwise convection, latent heat release, and contributing to intensification of storms. It has been shown that significant weather events, including explosive extratropical cyclones [2,3], rapid intensification of tropical cyclones [4], and heavy rainfall causing floods and flash floods [5,6] tend to follow arrivals of solar wind high-speed streams from coronal holes. To further support these results, we use various data sets in the superposed epoch analysis of the occurrence of severe weather, including heavy rainfall events and tornado outbreaks, in the context of solar wind coupling to the magnetosphere-ionosphere-atmosphere system. [1] Chen T.-C., et al., J. Atmos. Sci. 75, 2425–2443. doi:10.1175/JAS-D-17-0221.1 [2] Prikryl P., et al., J. Atmos. Sol.-Terr. Phys. 149, 219–231. doi:10.1016/j.jastp.2016.04.002 [3] Prikryl P., et al., J. Atmos. Sol.-Terr. Phys. 171, 94–10, 2018. doi:10.1016/j.jastp.2017.07.023 [4] Prikryl P., et al., J. Atmos. Sol.-Terr. Phys. 183, 36-60, 2019. doi:10.1016/j.jastp.2018.12.009 [5] Prikryl P., et al., Ann. Geophys. 39 (4), 769–93, 2021. doi:10.5194/angeo-39-769-2021 [6] Prikryl P., et al., Atmosphere 12 (9), 2021. doi:10.3390/atmos12091186.
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  • 67
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    In:  XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG)
    Publication Date: 2023-08-02
    Description: In GNSS, tropospheric Mapping Functions (MFs) are used to provide the relationship between slant and zenith delays. In order to regard asymmetry of the atmosphere, tropospheric gradients are taken into account. In this study, we present a new approach to parameterize the tropospheric delay and modify the wet MF with an additional parameter to decrease the errors in the analysis. Hence, we have calculated tropospheric delays on global scale using ray-tracing algorithm. ECMWF’s reanalysis ERA5 hourly datasets have been used with 0.25° horizontal resolution. According to the results, it can be concluded that the additional parameter is related to the humidity field. Since the humidity field is highly variable in space and time Numerical Weather Models will have difficulties to predict the additional parameter accurately.
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  • 68
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    In:  XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG)
    Publication Date: 2023-08-02
    Description: High-speed jets formed downstream of the Earth’s bow shock are localized and transient dynamic pressure enhancements. Due to their properties, they can have an effect on Earth’s magnetosphere, and they interact with background magnetosheath plasma. Jets have been connected to a variety of different effects, for example, magnetopause reconnection, excitation of ULF waves, and direct plasma penetration in the magnetosphere. While jets have been studied for several decades, their formation mechanism is still under debate. Several generation models have been proposed that include solar wind discontinuities, foreshock transients, non-stationarity of the shock (i.e., ripples/reformation) and many others. In this work, we focus on the connection between magnetosheath jets and the Earth’s bow shock. Specifically, we focus on observations of magnetosheath jets made by NASA’s Magnetosphere Multiscale (MMS) mission. Due to the high-resolution measurements, we found evidence of shock reformation allowing solar wind plasma to be less compressed than the typical magnetosheath, allowing the formation of magnetosheath jets as a direct consequence of the shock’s cyclic behaviour. Moving on, we exhibit how jets evolve at the Earth’s magnetosheath environment and how their velocity distribution functions (VDFs) can provide insight into their origin. Analyzing jets' VDFs highlights their kinetic nature and indicates the limitations of studying them from a full particle moment fluid picture. Finally, we investigate aspects of non-Maxwelianity that jets exhibit, and discuss how future research could include multiscale investigation made by conjunctions of several missions that reside in the outer magnetospheric region such as Cluster, MMS and THEMIS.
    Language: English
    Type: info:eu-repo/semantics/conferenceObject
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  • 69
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    In:  XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG)
    Publication Date: 2023-08-02
    Description: During eruptive crises, questions on the potential climate response to an eruption rapidly emerge within scientific communities, stakeholders, and the public. However, rapid prediction of the climatic response is challenging because of: i) the uncertainties associated with near-real time satellite estimates of volcanic emissions; ii) the fact that most climate model simulations require detailed aerosol optical properties to be run; and iii) the significant computational costs of and uncertainties associated with climate models with interactive stratospheric aerosol capabilities, which only require estimates of the initial volcanic sulfur emissions. To address this challenge, we developed Volc2Clim (https://volc2clim.bgs.ac.uk/), a webtool predicting volcanic radiative forcing and climate response from volcanic sulfur emissions. Volc2Clim combines three simple published models: EVA_H, which predicts perturbations in aerosol optical properties, such as the stratospheric aerosol optical depth (SAOD) for a given mass of sulfur dioxide (SO₂), injection altitude and injection latitude. A scaling factor that links the global-mean SAOD perturbation (at 550 nm) and the global-mean effective volcanic radiative forcing at the top of the atmosphere. FaIR, a simple climate response model that calculates the global-mean surface temperature response based on the global-mean effective volcanic radiative forcing. Volc2Clim is computationally inexpensive and outputs both simple metrics and figures characterizing the radiative forcing and climate response, as well as full 4-dimensionnal fields of aerosol optical properties required to run climate models. We will showcase Volc2Clim’s main functionalities and discuss how well it performs for recent eruptions such as that of Raikoke in 2019.
    Language: English
    Type: info:eu-repo/semantics/conferenceObject
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