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  • 2020-2024  (36,724)
  • 1985-1989  (516,827)
  • 2023  (36,723)
  • 1989  (274,651)
  • 1986  (242,242)
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Years
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  • 1
  • 2
    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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  • 3
    Call number: PIK N 453-17-91096
    Type of Medium: Monograph available for loan
    Pages: 50 Seiten , Illustrationen, Diagramme
    Language: German
    Location: A 18 - must be ordered
    Branch Library: PIK Library
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  • 4
    Monograph available for loan
    Monograph available for loan
    Leningrad : Gidrometeorolog. Izd.
    Call number: MOP 33767
    Type of Medium: Monograph available for loan
    Pages: 663 S.
    Language: Russian
    Note: In kyrill. Schr., russ.
    Location: MOP - must be ordered
    Branch Library: GFZ Library
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  • 5
    Monograph available for loan
    Monograph available for loan
    London : Penguin Books
    Type of Medium: Monograph available for loan
    ISBN: 9780141985206
    Language: English
    Branch Library: RIFS Library
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  • 6
    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: RIFS 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
    Type of Medium: Monograph available for loan
    Pages: Bände (Loseblattsammlung)
    ISBN: 9783963144509 , 3963144505
    Subsequent Title: Fortsetzung von EnEV und Energieausweise ...
    Language: German
    Branch Library: PIK Library
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  • 9
    Call number: MOP 19538/1d-6d
    Type of Medium: Monograph available for loan
    Pages: 111 S.
    ISSN: 0486-2287
    Language: Russian
    Note: In kyrill. Schr.
    Location: MOP - must be ordered
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  • 10
    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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  • 11
    Monograph available for loan
    Monograph available for loan
    Madrid : Secc
    Call number: PIK N 456-17-90913
    Type of Medium: Monograph available for loan
    Pages: 536 Seiten
    Series Statement: Ministerio de Transportes Turismo Y Comunicaciones : Publicación Serie A 114
    Parallel Title: 1,1=6; 2,1=13 von Publicaciones / D / Ministerio del Aire, Subsecretaria de Aviación Civil, Servicio Meteorológico Nacional
    Language: Spanish
    Location: A 18 - must be ordered
    Branch Library: PIK Library
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  • 12
    Call number: IASS 22.95033
    Type of Medium: Monograph available for loan
    Pages: 378 S , 225 mm x 135 mm
    ISBN: 3899421876 , 978-3-89942-187-3
    Series Statement: Edition panta rei
    Language: German
    Note: Zugl.: Marburg (Lahn), Univ., Habil.-Schr., 2004 u.d.T.: Gutmann, Mathias: Die Medialität des Erfahrens
    Branch Library: RIFS Library
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  • 13
    Call number: IASS 15.89494
    Type of Medium: Monograph available for loan
    Pages: Losebl.-Ausg.
    Edition: Stand: Oktober 2010
    ISBN: 9783768501828
    Language: German
    Branch Library: RIFS Library
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  • 14
    Call number: S 90.0066(162,1)
    In: Geologisches Jahrbuch / A
    Type of Medium: Series available for loan
    Pages: 261 Seiten , Ill., 1 DVD-ROM (12 cm) und 1 Tafel-Beil. ([2] S.)
    ISBN: 9783510968534
    Series Statement: Geologisches Jahrbuch 162
    Classification:
    Engineering Geophysics
    Language: German
    Location: Lower compact magazine
    Branch Library: GFZ Library
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  • 15
    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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  • 16
    Journal available for loan
    Journal available for loan
    München : Altop Verlag ; 2007 -
    Call number: Z 19.92410
    Type of Medium: Journal available for loan
    Pages: 30 cm
    ISSN: 1865-4266
    Former Title: Vorg. Nachhaltiges Wirtschaften in Deutschland
    Language: German
    Note: Ungezählte Beil. ab 2010: Special , Ersch. jährl. 4x
    Branch Library: RIFS Library
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  • 17
    Call number: (DE-599)GBV03709842X
    Type of Medium: Monograph available for loan
    Language: German
    Location: MOP - must be ordered
    Branch Library: GFZ Library
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  • 18
    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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  • 19
    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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  • 20
    Call number: AWI G6-19-92375
    In: Berichte / Christian-Albrechts-Universität zu Kiel, Institut für Geowissenschaften, Nr. 9
    Type of Medium: Monograph available for loan
    Pages: 278 Seiten , Illustrationen
    ISSN: 0175-9302
    Series Statement: Berichte / Christian-Albrechts-Universität zu Kiel, Institut für Geowissenschaften 9
    Language: German
    Note: Zugleich: Dissertation, Christian-Albrechts-Universität zu Kiel, 1999 , INHALTSVERZEICHNIS 1. Einleitung 1.1 Kenntnisstand und offene Fragen 1.2 Fragestellung und Ziele dieser Arbeit 2. Umweltbedingungen in den Arbeitsgebieten 2.1 Hydrographie, Eisverhältnisse und NAO 2.2 Zur Variation von Wassertiefe und Breite der Dänemarkstraße und zur Vereisung Islands während des letzten Glazials 3. Methoden 3.1 Auswahl der Kernstationen 3.2 Probennahme und Analysen (Übersicht) 3.3 Zur Rekonstruktion von Paläobedingungen im Oberflächenwasser Zur Aussage stabiler Isotopenverhältnisse in planktischen Foraminiferen Zur Messung stabiler Isotopenverhältnisse Zur Massenspektrometrie Zur Rekonstruktion von Oberflächentemperaturen Alkane und Alkohole als Maß für Staubeintrag Eistranspmtiertes Material und vulkanische Aschen 3.4 Zur Rekonstruktion von Paläobedingungen im Zwischen-/ Tiefenwasser Häufigkeit von Cibicides- und anderen benthischen Arten (inkl. Taxonomie) Stabile Isotopenverhältnisse in benthischen Foraminiferen 3.5 AMS 14C-Datierungen Probenreinigung 3. 6 Hauptelementanalysen von vulkanischen Asche-Leithorizonten 3. 7 Geomagnetische Meßgrößen und magnetische Suszeptibiltät 3.8 Techniken zur Spektralanalyse 4. Methodische Ergebnisse 4.1 Zum Einfluß der Probenreinigung auf δ18O-/ δ13C-Werte 4.2 Probleme bei der langfristigen Reproduzierbarkeit von δ18O-Zeitreihen 4.3 Einfluß der Korngröße und Artendefinition planktischer Foraminiferen auf SST-Rekonstruktionen in hohen Breiten 4.4 Vergleich der stabilen Isotopenwerte von Cibicides lobatulus und Cibicidoides wuellerstorfi 5. Stratigraphische Grundlagen und Tiefenprofile der Klimasignale 5.1 Stratigraphische Korrelation zwischen parallel-gekernten GKG- und SL-/KL-Profilen 5.2 Flanktische δ18O-/ δ13C-Kurven, 14C-Alter und biostratigraphische Fixpunkte Westliches Islandbecken Kern PS2644 Kern PS2646 Kern PS2647 Kern 23351 Vøring-Plateau Kern 23071 Kern 23074 5.3 Benthische δ18O-/ δ13C-Werte in Kern PS2644 5.4 Siliziklastische Sedimentkomponenten: Eistransportiertes Material Westliches Islandbecken Kern PS2644 Kern PS2646 Kern PS2647 Vøring-Plateau Kern 23071 Kern 23074 5.5 Vulkanische Glasscherben in Kern PS2644: Wind- und Eiseintrag 5.6 Geochemie und Alter einzelner Tephralagen als Leithorizonte Westliches Islandbecken Kern PS2644 Kern PS2646 Kern PS2647 Vøring-Plateau Kern 23071 Kern 23074 5.7 Magnetische Suszeptibilität in den Kernen PS2644, PS2646 und PS2647 Kern PS2644 Kern PS2646 und PS2647 5.8 Geomagnetische Feldintensität und Richtungsänderungen in Kern PS2644 5.9 Variation von Planktonfauna und -flora Westliches Islandbecken: Kern PS2644 Kern PS2646 und PS2647 Vøring-Plateau: Kern 23071 und 23074 5.10 Benthische Foraminiferen in Kern PS2644 6. Entwicklung von Temperatur und Salzgehalt nördlich der Dänemark-Straße 6.1 Variation der Oberflächentemperatur nach Planktonforaminiferen 6.2 Variation der Oberflächentemperatur nach Uk37 6.3 Variation der Oberflächensalinität 7. Die Feinstratigraphie von Kern PS2644 als Basis für eine Eichung der 14C-Altersskala 22 - 55 ka 7.1 Korrelation zwischen den Klimasignalen in Kern PS2644 und der GISP2-Klimakurve zum Kalibrieren der 14C-Alter und Erstellen eines Altersmodells Tephrachronologische Marker Korrelationsparameter und -regeln Sonderfälle/ Probleme bei der Korrelation 7.2 Alters-stratigraphische Korrelation der Klimakurven von Kern 23071 und 23074 7.3 Variation der Altersanomalien zwischen 20 und 55 14C-ka 7.4 Variabilität des planktischen 14C-Reservoiralters in Schmelzwasserbeeinflußten Seegebieten Variation der planktischen 14C-Alter unmittelbar an der Basis von Heinrich-Ereignis 4 Unterschiede zwischen planktischen und benthischen 14C-Altern in der westlichen Islandsee. Zur Erklärung der inversen Altersdifferenzen 7.5 Differenz zwischen 14C- und Kalenderalter: Zeitliche Variation unter Einfluß des Erdmagnetfeldes - Modell und Befund 7.6 Sedimentationsraten der Kerne 23071, 23074 und PS2644 nach dem GISP2-Altersmodell Vøring-Plateau: Kerne 23071 und 23074 Südwest-Islandsee: Kern PS2644 8. Klimaoszillationen im Europäischen Nordmeer in der Zeit und Frequenzdomäne 8.1 "Der Einzelzyklus" in den Klimakurven von Kern PS2644 8.2 Zur Veränderlichkeit der Warm- und Kaltextreme sowie Zyklenlänge Besonderheiten in der Zyklenlänge Variation der Kalt-(Stadiale) Variation der Interstadiale 8.3 Periodizitäten der Klimasignale im Frequenzband der D.-Oe.-Zyklen. Der D.-Oe.-Zyklus von 1470 J., seine Multiplen und harmonischen Schwingungen Weitere Frequenzen: 1000-1150 Jahre- und 490- 510 Jahre-Zyklizitäten Höhere Frequenzen im Bereich von Jahrhunderten und Dekaden 8.4 Phasenbeziehungen und (örtliche) Steuemngsmechanismen der Dansgaard-Oeschger-Zyklen 9. Schlußfolgerungen Danksagung Literaturverzeichnis Anhang
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  • 21
    Call number: AWI A3-20-93434
    In: Meteorologische Abhandlungen / Institut für Meteorologie und Geophysik der Freien Universität Berlin, Band XXXII, Heft 1
    Type of Medium: Series available for loan
    Pages: 121 Seiten , Illustrationen
    Series Statement: Meteorologische Abhandlungen / Institut für Meteorologie und Geophysik der Freien Universität Berlin 32,1
    Language: German
    Note: Zugleich: Dissertation, Freie Unversität Berlin, [ca. 1963] , INHALTSVERZEICHNIS PROBLEMSTELLUNG UND ZIELSETZUNG 1. BEMERKUNGEN ZUM BEOBACHTUNGSGELÄNDE UND ZUM BEOBACHTUNGSMATERIAL 1.1 Das Beobachtungsgelände 1.2 Das Beobachtungsmaterial 2. HOMOGENITÄTSBETRACHTUNGEN 2.1 Temperatur 2.2 Niederschlag 2.3 Wind 2.4 Sonnenschein und Bewölkung 3. TEMPERATURVERHÄLTNISSE 3.1 Monats- und Jahreswerte 3.2 Tageswerte 3.3 Pentadenwerte 3.4 Häufigkeitsbetrachtungen 3.5 Interdiurne Veränderlichkeit 3.6 Der tägliche Gang 3.7 Vorkommen bestimmter Schwellenwerte 3.71 Frost- und Eistage 3.72 Sommer- und Tropentage 4. DER WASSERGEHALT DER LUFT 4.1 Monats- und Jahreswerte 4.2 Tageswerte 4.3 Häufigkeitsbetrachtungen 4.4 Interdiurne Veränderlichkeit 4.5 Der tägliche Gang 5. BEWÖLKUNGSVERHÄLTNISSE 5.1 Monats- und Jahreswerte 5.2 Tageswerte 5.3 Häufigkeitsbetrachtungen 5.4 Der tägliche Gang 5.5 Heitere und trübe Tage 5.6 Nebel 6. SONNENSCHEIN 6.1 Monats- und Jahreswerte 6.2 Tageswerte 6.3 Der tägliche Gang 7. NIEDERSCHLAGSVERHÄLTNISSE 7.1 Monats- und Jahreswerte 7.2 Niederschlagsbereitschaft 7.3 Tageswerte 7.4 Der tägliche Gang 7.5 Häufigkeitsbetrachtungen 7.6 Niederschlags- und Trockenperioden 7.7 Niederschlag und Wind· 7.8 Schneeverhältnisse 7.81 Schneefall und Schneedecke 7.82 Schneehöhe 7.9 Gewitter 8. WINDVERHÄLTNISSE 8.1 Windrichtung 8.2 Windgeschwindigkeit 8.21 Der jährliche Gang 8.22 Häufigkeitsbetrachtungen 8.23 Sturmtage und Windstillen 8.24 Der tägliche Gang 9.ZUSAMMENFASSUNG VERZEICHNIS DER TEXTTABELLEN VERZEICHNIS DER ABBILDUNGEN LITERATURVERZEICHNIS TABELLENANHANG
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  • 22
    Call number: AWI A3-20-93434-2
    In: Meteorologische Abhandlungen / Institut für Meteorologie und Geophysik der Freien Universität Berlin, Band XXXII, Heft 2
    Type of Medium: Series available for loan
    Pages: 218 Seiten , Illustrationen
    Series Statement: Meteorologische Abhandlungen / Institut für Meteorologie und Geophysik der Freien Universität Berlin 32,2
    Language: German
    Note: Zugleich: Dissertation, Freie Unversität Berlin, [ca. 1963] , INHALTSVERZEICHNIS PROBLEMSTELLUNG UND ZIELSETZUNG 1. BEMERKUNGEN ZUM BEOBACHTUNGSGELÄNDE UND ZUM BEOBACHTUNGSMATERIAL 1.1 Das Beobachtungsgelände 1.2 Das Beobachtungsmaterial 2. HOMOGENITÄTSBETRACHTUNGEN 2.1 Temperatur 2.2 Niederschlag 2.3 Wind 2.4 Sonnenschein und Bewölkung 3. TEMPERATURVERHÄLTNISSE 3.1 Monats- und Jahreswerte 3.2 Tageswerte 3.3 Pentadenwerte 3.4 Häufigkeitsbetrachtungen 3.5 Interdiurne Veränderlichkeit 3.6 Der tägliche Gang 3.7 Vorkommen bestimmter Schwellenwerte 3.71 Frost- und Eistage 3.72 Sommer- und Tropentage 4. DER WASSERGEHALT DER LUFT 4.1 Monats- und Jahreswerte 4.2 Tageswerte 4.3 Häufigkeitsbetrachtungen 4.4 Interdiurne Veränderlichkeit 4.5 Der tägliche Gang 5. BEWÖLKUNGSVERHÄLTNISSE 5.1 Monats- und Jahreswerte 5.2 Tageswerte 5.3 Häufigkeitsbetrachtungen 5.4 Der tägliche Gang 5.5 Heitere und trübe Tage 5.6 Nebel 6. SONNENSCHEIN 6.1 Monats- und Jahreswerte 6.2 Tageswerte 6.3 Der tägliche Gang 7. NIEDERSCHLAGSVERHÄLTNISSE 7.1 Monats- und Jahreswerte 7.2 Niederschlagsbereitschaft 7.3 Tageswerte 7.4 Der tägliche Gang 7.5 Häufigkeitsbetrachtungen 7.6 Niederschlags- und Trockenperioden 7.7 Niederschlag und Wind· 7.8 Schneeverhältnisse 7.81 Schneefall und Schneedecke 7.82 Schneehöhe 7.9 Gewitter 8. WINDVERHÄLTNISSE 8.1 Windrichtung 8.2 Windgeschwindigkeit 8.21 Der jährliche Gang 8.22 Häufigkeitsbetrachtungen 8.23 Sturmtage und Windstillen 8.24 Der tägliche Gang 9.ZUSAMMENFASSUNG VERZEICHNIS DER TEXTTABELLEN VERZEICHNIS DER ABBILDUNGEN LITERATURVERZEICHNIS TABELLENANHANG
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  • 23
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Physics Letters B 294 (1992), S. 466-478 
    ISSN: 0370-2693
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Physics
    Type of Medium: Electronic Resource
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  • 24
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Physics Letters B 317 (1993), S. 474-484 
    ISSN: 0370-2693
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Physics
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  • 25
    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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  • 26
    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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  • 27
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    In:  Journal of Geophysical Research: Solid Earth
    Publication Date: 2023-01-06
    Description: The distance to failure of the upper crustal rock in the prevalent stress field is of importance to better understand fault reactivation by natural and induced processes as well as to plan and manage georeservoirs. In particular, the contemporary stress state is one of the key ingredients for this assessment. To provide a continuous description of the 3D absolute stress state geomechanical-numerical models are used. However, stress magnitude data for model calibration are sparse and incomplete and thus, the resulting model uncertainties are large. In order to reduce the uncertainties, we incorporate additional constraints on stress magnitudes to check the plausibility of different data-based stress states. We use formation integrity tests, borehole breakouts, drilling induced fractures, and observations of seismicity and distinct seismological quiescence. This information is weighted according to its confidence and the agreement with the different modelled stress states is assessed. The information is introduced to a Bayesian approach to estimate weights of the modelled stress states and thereby identify their plausibility. A case study in southern Germany shows the ability of the approach to identify from a wide range of stress states a small number of plausible ones and reject implausible stress states. This significantly reduces the number of stress states and thus lowers the model uncertainties.
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  • 28
    Publication Date: 2023-01-05
    Description: Hydrogen (δ2H) and oxygen (δ18O) isotopes of water extracted from speleothem fluid inclusions are important proxies used for paleoclimate reconstruction. In our study we use a cavity ring-down laser spectroscopy system for analysis and modified the approach of Affolter et al. (2014) for sample extraction. The method is based on crushing of small sub-gram speleothem samples in a heated and continuously water-vapour purged extraction line. The following points were identified: Injection of reference water shows a precision (1σ) of 0.4–0.5 ‰ for δ18O values and 1.1–1.9 ‰ for δ2H values for water amounts of 0.1–0.5 μl, which improves with increasing water amount to 0.1–0.3 ‰ and 0.2–0.7 ‰, respectively, above 1 μl. The accuracy of measurements of water injections and water-filled glass capillaries crushed in the system is better than 0.08 ‰ for δ18O and 0.3 ‰ for δ2H values. The reproducibility (1σ) based on replicate analysis of speleothem fluid inclusion samples with water amounts 〉0.2 μl is 0.5 ‰ for δ18O and 1.2 ‰ for δ2H values, respectively. Isotopic differences between the water vapour background of the extraction system and the fluid inclusions have no significant impact on the measured fluid inclusion isotope values if they are within 10 ‰ for δ18O and 50 ‰ for δ2H values of the background. Tests of potential adsorption effects with inclusion free spar calcite confirm that the isotope values are unaffected by adsorption for water contents of about 1 μl (fluid inclusion) water per g of carbonate or above. Fluid inclusion analysis on three different modern to late Holocene speleothems from caves in northwest Germany resulted in δ18O and δ2H values that follow the relationship as defined by the meteoric water line and that correspond to the local drip water. Yet, due to potential isotope exchange reactions for oxygen atoms, hydrogen isotope measurements are preferentially to be used for temperature reconstructions. We demonstrate this in a case study with a Romanian stalagmite, for which we reconstruct the 20th century warming with an amplitude of approximately 1 °C, with a precision for each data point of better than ±0.5 °C.
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  • 29
    Publication Date: 2023-01-09
    Description: The characterisation of the gas state under electron impact is of high importance for the understanding of materials in-situ environmental transmission electron microscopy (ETEM) experiments. We report on the formation of a dilute plasma state of Ar and He based on the development of a Langmuir probe as a plasma diagnostic tool for the differentially pumped volume at the TEM sample position in the octagon. In order to keep stray magnetic field influences of the objective lens small, and thus the results readily interpretable within existing theory, the experiments are performed in Lorentz mode. The applicability of Langmuir type analysis for the identification of plasma parameters, such as ion density, plasma temperature, sheath extension and electron energy distribution is examined. The systematic study as a function of gas pressure and beam current reveals cold plasma characteristics with electron temperatures of around 0.4 eV and ion and electron densities that are orders of magnitude below the expected values from ionisation cross sections. The loss of charged particles appears to be due to surface collisions at the electrically conducting pole piece surfaces as well as at the conductive parts of the TEM holder.
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  • 30
    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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  • 31
    Publication Date: 2023-01-11
    Description: The Groß Schönebeck site in the North German Basin serves as research platform to study the geothermal potential of deeply buried Permian reservoir rocks and the technical feasibility of heat extraction. The structural setting of the site was investigated in more detail by a newly acquired 3D-seismic survey to improve the former conceptual model that was based on several old 2D seismic lines. The new data allow a revision of the geological interpretation, enabling the setup of a new reservoir model and providing base information for a possible further site development of Permo-Carboniferous targets. The 3D seismic allows for the first time a consistent geological interpretation and model parameterization of the well-studied geothermal site. Main reflector horizons and the corresponding stratigraphic units were mapped and the structural pattern of the subsurface presented in the 8 km × 8 km × 4 km large seismic volume. Attribute analysis revealed some fracture and fault patterns in the upper Zechstein and post-Permian units, while formerly hypothesized large offset faults are not present in the Rotliegend reservoir. However, a well-established graben-like structure at the top of the Zechstein succession is most likely related to broken anhydritic brittle intra-salt layers of some meter of thickness. Most reflectors above the salt show a rather undisturbed pattern. The main reservoir sandstone of the Dethlingen Formation (Rotliegend) was mapped and characterized. The base of the underlying Permo-Carboniferous volcanic rock sequence and hence its thickness could not be depicted reliably from the geophysical data. Based on the seismic data and the available reconnaissance drilling, logging, and laboratory data of the Groß Schönebeck research site, the thickness and distribution of the sedimentary Rotliegend (with emphasis of the sandy reservoir section) and of the volcanic rock sequence was modelled and stochastically parameterized with petrophysical properties guided by seismic facies pattern correlation, providing a more realistic reservoir description. Properties include total and effective porosity, permeability, bulk density, thermal conductivity, thermal diffusivity, and specific heat capacity. The data and interpretation constitute the basis for a better understanding of the thermo and hydromechanical processes at the site and for future measures. Further site development could include a deepening of one well to provide evidence on the volcanic rock sequence and consider deviated wells into favourable zones and the design of a fracture-dominated utilization approach.
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  • 32
    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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  • 33
    Publication Date: 2023-01-10
    Description: Mid-plate upward mantle flow is a key component of global mantle convection, but its patterns are poorly constrained. Seismic anisotropy is the most direct way to infer mantle flow as well as melt distribution, yet the convection patterns associated with plume-like mantle upwelling are understudied due to limited seismic data coverage. Here, we investigate seismic anisotropy beneath the Madeira and Canary hotspots using a dense set of shear wave splitting observations and combining teleseismic and local events recorded by three-component broadband and short-period seismic stations. Using a total of 26 stations in the Madeira archipelago and 43 stations around the Canary Islands, we obtain 655 high quality measurements that reveal heterogeneous flow patterns. Although local event results are sparse around most islands, we can observe a small average of S-wave splitting times of 0.16 ± 0.01 s, which significantly increase with source depth beneath El Hierro (〉20 km) and Tenerife (〉38 km) up to 0.58 ± 0.01 s and 0.47 ± 0.05 s. This suggests an influence of melt pocket orientation in magma reservoirs developed at uppermost-mantle depths. Likewise, anisotropy increases significantly beneath the islands with shield stage volcanism (up to 9.81 ± 1.78% at El Hierro, western Canaries, against values up to 1.76 ± 0.73% at Lanzarote, eastern Canaries). On average, teleseismic SKS-wave splitting delay times are large (2.19 ± 0.05 s), indicating sublithospheric mantle flow as the primary source for anisotropy in the region. In the Canaries the western islands show significantly smaller average SKS delay times (1.93 ± 0.07 s) than the eastern ones (2.25 ± 0.11 s), which could be explained by destructive interference above the mantle upwelling. Despite complex patterns of fast polarisation directions throughout both regions, some azimuthal pattern across close stations can be observed and related to present-day mantle flow and anisotropy frozen in the lithosphere since before 60 Ma. Additionally, we infer that the current presence of a mantle plume beneath the archipelagos leads to the associated complex, small-scale heterogeneous anisotropy observations.
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  • 34
    Publication Date: 2023-01-10
    Description: Mofettes are gas emission sites where high concentrations of CO2 ascend through conduits from as deep as the mantle to the Earth’s surface and as such provide direct windows to processes at depth. The Hartoušov mofette, located at the western margin of the Eger Graben, is a key site to study interactions between fluids and swarm earthquakes. The mofette field (10 mofettes within an area of 100 m × 500 m and three wells of 28, 108, and 239 m depth) is characterized by high CO2 emission rates (up to 100 t/d) and helium signatures with (3He/4He)c up to 5.8 Ra, indicating mantle origin. We compiled geological, geophysical, geochemical, and isotopic data to describe the mofette system. Fluids in the Cheb basin are mixtures between shallow groundwater and brine (〉40 g/L at a depth of 235 m) located at the deepest parts of the basin fillings. Overpressured CO2-rich mineral waters are trapped below the mudstones and clays of the sealing Cypris formation. Drilling through this sealing layer led to blow-outs in different compartments of the basin. Pressure transients were observed related to natural disturbances as well as human activities. External (rain) and internal (earthquakes) events can cause pressure transients in the fluid system within hours or several days, lasting from days to years and leading to changes in gas flux rates. The 2014 earthquake swarm triggered an estimated excess release of 175,000 tons of CO2 during the following four years. Pressure oscillations were observed at a wellhead lasting 24 h with increasing amplitudes (from 10 to 40 kPa) and increasing frequencies reaching five cycles per hour. These oscillations are described for the first time as a potential natural analog to a two-phase pipe–relief valve system known from industrial applications.
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  • 35
    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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  • 36
    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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  • 37
    Publication Date: 2023-01-13
    Description: On 12 November 2017, an earthquake with a moment magnitude of 7.3 struck the west of Iran near the Iraq border. This event was followed about 9 and 12 months later by two large aftershocks of magnitude 5.9 and 6.3, which together triggered intensive seismic activity known as the 2017–2019 Kermanshah sequence. In this study, we analyse this sequence regarding the potential to forecast the spatial aftershock distribution based on information about the main shock and its largest aftershocks. Recent studies showed that classical Coulomb failure stress (CFS) maps are outperformed by alternative scalar stress quantities, as well as a distance-slip probabilistic model (R) and deep neural networks (DNN). In particular, the R-model performed best. However, these test results were based on the receiver operating characteristic (ROC) metric, which is not well suited for imbalanced data sets such as aftershock distributions. Furthermore, the previous analyses also ignored the potential impact of large secondary earthquakes. For the complex Kermanshah sequence, we applied the same forecast models but used the more appropriate MCC-F1 metric for testing. Similar to previous studies, we also observe that the receiver independent stress scalars yield better forecasts than the classical CFS values relying on the specification of receiver mechanisms. However, detailed analysis based on the MCC-F1 metric revealed that the performance depends on the grid size, magnitude cut-off and test period. Increasing the magnitude cut-off and decreasing the grid size and period reduce the performance of all methods. Finally, we found that the performance of the best methods improves when the source information of large aftershocks is additionally considered, with stress-based models outperforming the R model. Our results highlight the importance of accounting for secondary stress changes in improving earthquake forecasts.
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  • 38
    Publication Date: 2023-01-16
    Description: Tierra del Fuego in Argentina is a unique location to examine past Holocene wind variability since it intersects the core of the Southern Hemisphere Westerly Winds (SHWW). The SHWW are the most powerful prevailing winds on Earth. Their variation plays a role in regulating atmospheric CO2 levels and rainfall amounts and distribution, both today and in the past. We obtained a piston core (LF06-PC8) from Bahía Grande, a protected sub-basin at the southern margin of Lago Fagnano, the largest lake in Tierra del Fuego. This article focuses on the uppermost 185 cm of this core, corresponding to laminated sediment from the last ~6.3 ka. Laminations consist of millimetre-scale paired dark and light layers. Previous studies and new geochemical analysis show that the dark and light layers are characterized by differing concentrations of Mn and Fe. We attribute the distribution of Mn and Fe to episodic hypolimnic oxic–anoxic variations. The age model suggests an approximately bidecadal timescale for the formation of each layer pair. We propose a new model of these redox changes with the SHWW variations. The most likely phenomenon to produce complete water-column mixing is thermobaric instability, which occurs in colder winters with low-intensity SHWW (El Niño-like conditions). In contrast, windier winters are characterized by higher temperatures and reduced mixing in the water column, facilitating a decline in oxygen concentration. Laminations, and the inferred presence of periodic hypolimnion redox changes, are common features of the past ~6.3 ka. Geochemical proxy variability is compatible with an intensification of El Niño/Southern Oscillation activity during the past ~2 ka.
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  • 39
    Publication Date: 2023-01-16
    Description: Holocene environmental and climate change on the Tibetan Plateau is intensively studied and discussed with the aim to better understand the factors controlling the hydrology of individual river catchments and especially the availability of water which is of utmost significance for the communities downstream in times of rapid climate change. Thus, a late glacial and Holocene sediment record from Lake Heihai in the Kunlun-Pass region was investigated using ostracod and geochemical analyses. Cold and dry conditions were inferred between ca. 12.9 and 12.3 cal ka BP and higher temperatures before and afterwards. The cold spell probably corresponds to the Younger Dryas (YD) event in the North Atlantic region. Warmer and wetter conditions with highest lake levels and decreased lake-water salinity were recorded from ca. 10.8 to 7.0 cal ka BP when the summer monsoon was strengthened. The cold 8.2 cal ka BP event is not significantly recorded in the region probably due to the predominance of the summer monsoon over the westerlies. A declined lake level and increased lake-water salinity as the result of cold and dry conditions are inferred from ca. 7.0 to 4.5 cal ka BP when the strengthening of the mid-latitude westerly circulation probably triggered glacier advances in the catchment. An even lower lake level existed during cold conditions with glacier advances from ca. 4.5 to 1.2 cal ka BP. The level of Lake Heihai rose again after ca. 1.2 cal ka BP due to warmer conditions, causing the retreat of glaciers and higher runoff. Our record from the Kunlun Pass region provides further evidence for the catchment-specific response of hydrographical systems which are partly controlled by glaciers as major water sources.
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  • 40
    Publication Date: 2023-01-17
    Description: Interpreting cooling ages from multiple thermochronometric systems and/or from steep elevation transects with the help of a thermal model can provide unique insights into the spatial and temporal patterns of rock exhumation. Although several well-established thermal models allow for a detailed exploration of how cooling or exhumation rates evolved in a limited area or along a transect, integrating large, regional datasets in such models remains challenging. Here, we present age2exhume, a thermal model in the form of a MATLAB or Python script, which can be used to rapidly obtain a synoptic overview of exhumation rates from large, regional thermochronometric datasets. The model incorporates surface temperature based on a defined lapse rate and a local relief correction that is dependent on the thermochronometric system of interest. Other inputs include sample cooling age, uncertainty, and an initial (unperturbed) geothermal gradient. The model is simplified in that it assumes steady, vertical rock uplift and unchanging topography when calculating exhumation rates. For this reason, it does not replace more powerful and versatile thermal–kinematic models, but it has the advantage of simple implementation and rapidly calculated results. We also provide plots of predicted exhumation rates as a function of thermochronometric age and the local relief correction, which can be used to simply look up a first-order estimate of exhumation rate. In our example dataset, we show exhumation rates calculated from 1785 cooling ages from the Himalaya associated with five different thermochronometric systems. Despite the synoptic nature of the results, they reflect known segmentation patterns and changing exhumation rates in areas that have undergone structural reorganization. Moreover, the rapid calculations enable an exploration of the sensitivity of the results to various input parameters and an illustration of the importance of explicit modeling of thermal fields when calculating exhumation rates from thermochronometric data.
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  • 41
    Publication Date: 2023-01-18
    Language: English
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  • 42
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    Publication Date: 2023-01-18
    Language: English
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  • 43
    Publication Date: 2023-01-18
    Language: English
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  • 44
    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.
    Language: English
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  • 45
    Publication Date: 2023-01-18
    Language: English
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  • 46
    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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  • 47
    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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  • 48
    Publication Date: 2023-01-23
    Description: Fourier transform-ion cyclotron resonance-mass spectrometry (FT-ICR-MS) with negative ion electrospray ionization (ESI-N) and positive ion atmospheric pressure photoionization (APPI-P), and compound-specific carbon isotope measurements together with conventional biomarker analyses were applied on 13 crude oil samples from Cretaceous reservoirs in the Shushan, Dahab/Mireir, and Abu Gharadig basins of the northern Western Desert of Egypt to identify their origin, maturity, alteration level, and petroleum relationships. Five oil families were identified, and the FT-ICR-MS data enabled a differentiation between crude oils with terrigenous, marine, and mixed organic matter input based on polar compounds. The dominance of acidic (ESI-N) and low-polarity (APPI-P) oxygen-containing compounds in the Shushan oils reflects land plant material input and oxic depositional conditions for their source rocks. The abundance of oxygen-containing compounds gradually decreases in the NE-Abu Gharadig and Dahab/Mireir oils (source rocks: mixed Type III/II organic matter (OM)) to reach minimum values in the marine-dominated Abu Gharadig oils. Based on compound-specific carbon isotopes and hydrocarbon biomarkers, the Shushan Basin hosts two different oil families from source rocks with Type III OM that likely reveal different thermal maturities and ages. The detected APPI-P aromatic hydrocarbons together with other molecular maturity ratios suggest a higher thermal maturity for the Shushan family A and Abu Gharadig oils than for oils of Shushan family B and from the Dahab/Mireir Basins, respectively.
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  • 49
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    In:  Grundlagen der Informationswissenschaft
    Publication Date: 2023-01-23
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  • 50
    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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  • 51
    Publication Date: 2023-01-23
    Description: Forests contribute to climate change mitigation through carbon storage and uptake, but the extent to which this carbon pool varies in space and time is still poorly known. Several Earth Observation missions have been specifically designed to address this issue, for example, NASA's GEDI, NASA-ISRO's NISAR and ESA's BIOMASS. Yet, all these missions' products require independent and consistent validation. A permanent, global, in situ, site-based forest biomass reference measurement system relying on ground data of the highest possible quality is therefore needed. Here, we have assembled a list of almost 200 high-quality sites through an in-depth review of the literature and expert knowledge. In this study, we explore how representative these sites are in terms of their coverage of environmental conditions, geographical space and biomass-related forest structure, compared to those experienced by forests worldwide. This work also aims at identifying which sites are the most representative, and where to invest to improve the representativeness of the proposed system. We show that the environmental coverage of the system does not seem to improve after at least the 175 most representative sites are included, but geographical and structural coverages continue to improve as more sites are added. We highlight the areas of poor environmental, geographical, or structural coverage, including, but not limited to, Canada, the western half of the USA, Mexico, Patagonia, Angola, Zambia, eastern Russia, and tropical and subtropical highlands (e.g. in Colombia, the Himalayas, Borneo, Papua). For the proposed system to succeed, we stress that (1) data must be collected and processed applying the same standards across all countries and continents; (2) system establishment and management must be inclusive and equitable, with careful consideration of working conditions; and (3) training and site partner involvement in downstream activities should be mandatory.
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  • 52
    Publication Date: 2023-01-23
    Language: German
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  • 53
    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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  • 54
    Publication Date: 2023-01-23
    Description: The Earth’s magnetic field traps charged particles which are transported longitudinally around Earth, generating a near-circular current, known as the ring current. While the ring current has been measured on the ground and space for many decades, the enhancement of the ring current during geomagnetic storms is still not well understood, due to many processes contributing to its dynamics on different time scales. Here, we show that existing ring current models systematically overestimate electron flux observations of 10–50 keV on the nightside during storm onset. By analyzing electron drift trajectories, we show that this systematic overestimation of flux can be explained through a missing loss process which operates in the pre-midnight sector. Quantifying this loss reveals that the theoretical upper limit of loss has to be reached over a broad region of space in order to reproduce the observations. This missing loss may be attributed to inaccuracies in the parameterization of the loss due to chorus wave interactions, combined with the scattering by electrostatic electron cyclotron harmonic waves which is currently not included in ring current models.
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  • 55
    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.
    Language: English
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  • 56
    Publication Date: 2023-01-23
    Description: Am 24. November 2022 veranstaltete das Helmholtz Forum Forschungssoftware eine Informationsveranstaltung zu aktuellen Entwicklungen im Bereich Forschungssoftware in Helmholtz. Das Helmholtz Forum Forschungssoftware wird gemeinsam von der Task Group Forschungssoftware des AK Open Science und dem HIFIS Software Cluster getragen. Die Veranstaltung wurde unter dem Titel „3. Helmholtz Open Science Forum Forschungssoftware“ vom Helmholtz Open Science Office organisiert. Eine erste Veranstaltung des Helmholtz Forum Forschungssoftware fand im Mai 2021 und eine zweite im April 2022 statt. Der vorliegende Bericht dokumentiert die erfolgreiche Veranstaltung, an der rund 90 Mitarbeitende aus Helmholtz teilgenommen haben.
    Language: German
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  • 57
    Publication Date: 2023-01-27
    Description: Knowledge about the timing, amplitude and spatial gradients of Holocene environmental variability in the circum-Baltic region is key to understanding its responses to ongoing climate change. Based on a multi-dating and proxy approach, we reconstruct changes in productivity using total organic carbon (TOC) contents in sediments of Lake Kälksjön (KKJ) from west–central Sweden spanning the last 9612 (+255 − 114) years. An exception is the period from 1878 CE until today, in which sedimentation was dominated by anthropogenic lake level lowering and land use. In-lake productivity was higher during periods of warmer winters with shortened ice cover and prolonged growing seasons. A multi-millennial increase in productivity throughout the last ∼ 9600 years is associated with progressively warmer winters in northwestern Europe, likely triggered by the coinciding increase in Northern Hemisphere winter insolation. Decadal to centennial periods of higher productivity in KKJ tend to correspond to warmer winters during a more positive North Atlantic Oscillation (NAO) polarity, as reconstructed for the last 8000 years. In consequence, we assume our decadal to centennial productivity record from KKJ sediments for the complete ∼ 9600 years to provide a qualitative record of NAO polarity. A shift towards higher productivity variability at ∼ 5450 cal a BP is hypothesized to reect a reinforcement of NAO-like atmospheric circulation variability, possibly driven by more vigorous changes in North Atlantic deep-water formation.
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  • 58
    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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  • 59
    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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  • 60
    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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  • 61
    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.
    Language: English
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  • 62
    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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  • 63
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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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  • 64
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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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  • 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 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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  • 66
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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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  • 67
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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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  • 68
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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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  • 69
    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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  • 70
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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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  • 71
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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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  • 72
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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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  • 73
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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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  • 74
    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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  • 75
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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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  • 76
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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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  • 77
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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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  • 78
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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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  • 79
    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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  • 80
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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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  • 81
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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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  • 82
    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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  • 83
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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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  • 84
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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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  • 85
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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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  • 86
    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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  • 87
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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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  • 88
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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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  • 89
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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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  • 90
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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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  • 91
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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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  • 92
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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
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  • 93
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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
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  • 94
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    In:  XVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG)
    Publication Date: 2023-08-02
    Description: Human-induced climate change is increasing the frequency of heat waves and heavy rainfall, and their impacts have begun to manifest themselves in the form of various health hazards, wildfires, floods, and other types of damaging events. Significant risks can arise when the magnitudes of climate change exceed the adaptive capacity of a region. An unprecedented climatic risk could potentially have serious impacts on socioeconomic systems. Considering the adaptability to extreme climatic risks in the future, this study focused on determining whether humans have been exposed to the risks before, and defined the rim of two-dimensional histograms of population under 20-year extreme temperature and precipitation as a climatic risk boundary. It was revealed that more than 30% (16.3%) of world population in South Asia, sub-Saharan Africa, and other regions will transgress the climatic risk boundary by the end of this century under RCP8.5 (RCP2.6) scenario. Furthermore, under the assumption that the acceptability of adaptation measures currently adopted by people in other regions cannot avoid the influence of cultural and social aspects, regional climate risk boundary for people in each region is also developed. While many areas with large cities will remain within the global climatic risk boundary, they will transgress their regional climatic risk boundaries. This study shows that it is also necessary to consider the limits to adaptation for each appropriate area, considering the cultural, technological, and social transferability of adaptation, and will help refine public perceptions of extreme climatic risks and lead to more efficient policy making.
    Language: English
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  • 95
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    In:  XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG)
    Publication Date: 2023-08-02
    Description: The lower limb of the Meridional Overturning Circulation fills the abyssal ocean across much of the globe with Antarctic Bottom Water (AABW). However, this abyssal overturning cell only outcrops in the Southern Ocean; it depends upon rapid water mass transformation that occurs in a small number of distinct sites near the Antarctic continent, coupled with export of dense water from the Antarctic continental shelf. This strong dependence on local processes has compromised the fidelity of global models in representing the abyssal overturning - particularly for low-resolution climate models. Recent advances in high-resolution global ocean-sea ice models has led to significant improvements in model representation of AABW processes and has allowed deeper investigation into the dynamics of the lower cell of the MOC. In this presentation I will review recent progress in using high-resolution models to understand the dynamics of dense water export from the Antarctic, the sensitivity of dense water formation and the abyssal MOC to surface forcing, the variation of the AABW export and the pathways of AABW throughout the deep ocean. These advances help to constrain future potential changes in the lower overturning cell, and suggest methods to diagnose change from observations.
    Language: English
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  • 96
    Publication Date: 2023-08-02
    Description: The benefit of continuous modelling in hydrological studies is widely recognized, indeed it is particularly promising for estimating the design hydrological input for a variety of practical applications and there is a clear tendency to overcome the concept of design hydrograph in favor of the design runoff simulation. Recently, it was underlined the possibility and the opportunity to apply the continuous framework also in the challenging case of ungauged basins. However, while promising, this approach is still not commonly adopted in practice mainly because it needs as input a simulated rainfall time series, that still is not user-friendly task. In this contribution we summarize the recent steps forward of the continuous modelling in ungauged basins and the residual procedural bottlenecks, moreover we explore its use for designing flood early warning systems. We illustrate a framework based on hydrological-hydraulic synthetic scenarios for selecting the best-performing machine learning model for forecasting discharges. Finally, feature importance measures are introduced for discerning the most influential sub-basins where the measurement instrumentations should be installed enabling the implementation of a cost-effective flood early warning system.
    Language: English
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  • 97
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    In:  XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG)
    Publication Date: 2023-08-02
    Description: The gravity field plays a crucial role in Earth System Sciences. Currently available static global gravity field models are limited in resolution due to the band-limited spectral content of the input data from satellite observations and gravity measurements on the Earth’s surface. Such models are complemented beyond their current limits using high-resolution digital elevation models (DEMs) and density estimates. At GFZ, we are interested in developing such high-resolution topographic models to enhance the representation of static global gravity field models such as EIGEN-6C4. Our preliminary study expanded the model representation of EIGEN-6C4 up to d/o 5400 using Earth2014 and four density values estimated for rock, ocean, lake and ice. Moreover, we tested the impact of different shell thicknesses to the numerical stability and computation time. Current study is a continuation of our previous activities and summarises the first results of a DFG project GRAV4GEO (GRAVitational field modelling of Earth’s topography For GEOdetic and GEOphysical applications). We aim to improve the performance of our preliminary model ROLI_EllApprox_SphN_3660 further via introducing improved DEM and laterally varying density estimations and optimized methodology. Our preferred DEM model will be a product of combined solutions from TanDEM-X 90 m and other state-of-the-art DEM models developed/improved recently. Moreover, we aim to introduce a 3D density estimation globally. The new model is expected to enhance our preliminary model and contribute to the accurate representation of very high-resolution static global gravity field modelling.
    Language: English
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  • 98
    Publication Date: 2023-08-02
    Description: The PAGER project provides space weather predictions that are initiated from observations on the Sun and predicts radiation in space and its effects on satellite infrastructure. Real-time predictions and a historical record of the dynamics of the cold plasma density and ring current allow for evaluation of surface charging, and predictions of the relativistic electron fluxes allow for the evaluation of deep dielectric charging. The project provides a 1-2 day probabilistic forecast of ring current and radiation belt environments, which will allow satellite operators to respond to predictions that present a significant threat. As a backbone of the project, we use the most advanced codes that currently exist and adapt existing codes to perform ensemble simulations and uncertainty quantifications. This project includes a number of innovative tools including data assimilation and uncertainty quantification, new models of near-Earth electromagnetic wave environment, ensemble predictions of solar wind parameters at L 1, and data-driven forecast of the geomangetic Kp index and plasma density. Our developed codes may be used in the future for realistic modelling of extreme space weather events. The PAGER consortium is made up of leading academic and industry experts in space weather research, space physics, empirical data modelling, and space environment effects on spacecraft from Europe and the US.
    Language: English
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  • 99
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    In:  XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG)
    Publication Date: 2023-08-08
    Description: In November 2022 the new United Nations Global Geodetic Centre of Exellence has been established at the UN Campus in Bonn. The main task of the UN-GGCE is to assist the UN Member States to implement the goals of the UN-Resolution 69/266 from 26 February 2015: ‘Global Geodetic Reference Frame for Sustainable Development (GGRF)’. The GGRF is an authoritative, reliable, highly accurate and global spatial referencing infrastructure. With its high accuracy and long-term stability, it provides a reliable reference for precise positioning on the Earth and is the basis for monitoring changes of the Earth system. Quantification of numerous and diverse societal and scientific applications, like monitoring of sea level change, glacial melt or movement of tectonic plates are not possible without a reliable GGRF. The objective of UN-GGCE is therefore to support the implementation of the UN General Assembly resolution through strengthening and advancing: global geodetic cooperation and coordination; worldwide geodetic infrastructure; standards, policies and conventions; education, training and capacity building; and communication and awareness, while also coordinating measures and overseeing their implementation. The UN-GGCE will improve global cooperation and coordination between Member States and other geodetic stakeholders and focus on the establishment of a globaly coordinated geodetic infrastructure enabling all Member States and geodetic stakeholders to work more efficiently and effectively together.
    Language: English
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  • 100
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    In:  XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG)
    Publication Date: 2023-08-08
    Description: Major economic losses are caused by the presence of low visibility weather conditions such as fog, which happens frequently all year around in the United Arab Emirates (UAE). An accurate forecast of fog initiation and dissipation are vitally important to mitigate these losses, which includes air traffic delays, car damage and loss of life. The study reported here aims to investigate whether releasing electrically charged corona ions into fog can modify fog droplet properties and help to dissipate fog. Measurements of Potential Gradient (PG), visibility and droplet size distribution were made from an internal desert region of the UAE where radiation fog formation is common. Experiments were devised in which an array of four corona ionisers were pulsed on and off at regular time intervals. Preliminary tests were conducted in clear air conditions, to investigate the magnitude of changes in PG, which were found to be from 50 to 80 V/m when ions were released. Further analysis conducted in fog cases will also be reported here to investigate the effects of corona emitted ions on droplet size distribution and thus, examine if charging can modify fog droplet size and number concentration.
    Language: English
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