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HUST-Grace2026s: unconstrained GRACE and GRACE Follow-On static gravity field solution

The new unconstrained static gravity field HUST-Grace2026s is recently developed at Huazhong University of Science and Technology. During retrieving our model, the reprocessed GRACE L1b RL03 data and GRACE-FO RL04 data are used, and the newly de-aliasing product AOD1B RL07 is applied in the time span from 2002-04 to 2025-03. In addition, a hybrid processing chain is applied to improve the quality of final solutions. Further details are presented in Zhou et al. (2024) and Zheng et al. (2026).

Kernbohrungen im kalten Firn und Permafrost

Glaziologische Studien (Geophysik, Geodaesie, Fliessmodelle) werden auf dem Colle Gnifetti (Monte Rosa, kalter Firn) und am Piz Corvatsch (Oberengadin, Permafrost) durchgefuehrt. Die Resultate dienen als Grundlage fuer die Analyse von Bohrkernen in Firn, Eis und Permafrost. Anhand dieser Bohrkerne wird die Geschichte der Atmosphaerenzusammensetzung (v.a. Luftverschmutzung) und der Grundwassercharakteristik vor der Zeit direkter Messungen rekonstruiert. Dabei geht es in erster Linie um Basiswerte aus der vorindustriellen Zeit. Die Glaziologie betrachtet in diesem Rahmen vor allem Einbettungsverhaeltnisse der gespeicherten Umweltinformation und die involvierten Zeitskalen.

Analysen von Eisbohrkernen von alpinen Gletschern

Eiskerne aus kalten alpengletschern beinhalten die Information ueber Niederschlaege - und damit der atmosphaerischen Zusammensetzung - vergangener Zeiten. Auf dem Colle Gnifetti (4450 m ue.M.) im Monte Rosa-Gebiet wurden Kernbohrungen bis auf das Felsbett niedergebracht, die die Information ueber einen Zeitraum von etwa 500-1000 Jahren umfassen. Die wichtigsten Ziele sind: - Erfassen der natuerlichen Variabilitaet der atmosphaerischen Spurenstoffe (vor allem der Saeurebildner) und Ihres anthropogen bedingten Anstiegs; - Geschichte der Staubtransporte (Saharastaub) nach Mitteleuropa und ihre klimatische Information; - Vergleich der im Bohrkern gewonnenen Information mit mitteleuropaeischen Klimadaten (instrumentell und historisch).

Analysen von Eisbohrkernen von polaren Eisschilden

Eisproben, die feste Niederschlaege aus frueheren Epochen repraesentieren, werden durch Kernbohrungen auf polaren Eisschilden gesammelt. Bei Tiefbohrungen werden Proben von mehr als 100'000 Jahren Alter erhalten. Die Proben werden in unserem Labor auf Gasgehalt und Gaszusammensetzung, Gehalt radioaktiver Spuren und Saeurekonzentration analysiert. Die Resultate geben Aufschluss ueber die Umweltbedingungen zur Zeit des Niederschlags. Wichtigste Zielsetzungen sind: - Vorindustrieller Wert der CO2-Konzentration der Atmosphaere bestimmen - Natuerliche Schwankungen der atm. CO2-Konzentration und Auswirkungen auf - globales Klima untersuchen; - Ursachen der natuerlichen CO2-Schwankungen suchen; - Geschichte der globalen Auswirkung von Vulkanausbruechen rekonstruieren; - Veraenderungen der kosmischen Strahlung in der Vergangenheit untersuchen.

Monitoring der 'Equilibrium-Line-Altitude (ELA)' auf alpin. Gletschern mittels hochaufloesender Satellitenaufnahmen als Indikator fuer Klimaaenderungen

Mit Hilfe der Satelliten-Fernerkundung soll ein kontinuierliches Ueberwachungsprogramm zur Erfassung wichtiger glaziologischer Parameter aufgebaut werden, insbesondere von ELA (Equilibrium-Line-Altitude) und AAR (Accumulation Area Ratio). Daraus lassen sich wiederum Gletscher-Massenbilanz-Klimabeziehungen ableiten. Durch laengerfristige Beobachtung des Verhaltens eines Gletschers und durch regionale Vergleiche sollen sowohl Hinweise auf Klimaschwankungen und -veraenderungen abgeleitet, als auch Rueckschluesse auf Massenbilanz der Gletscher und damit auf das Abflussregime gewonnen werden.

Gletscher und Klima

Mit Hilfe der direkt im Satellitenbild erkennbaren Grenzen (Firnlinie und/oder Schneegrenze) wird der Verlauf der Gleichgewichtslinie und daraus der ELA (equilibrum line altitude) sowie zukuenftig auch die AAR (accumulation area ratio) untersucht. Daraus sollen regionale und zeitliche Veraenderungen abgeleitet und Zusammenhaenge zwischen Gletscherhaushalt, Wasserabfluss und Klima gewonnen werden.

Global Gravity-based Groundwater Product (G3P)

The Global Gravity-based Groundwater Product (G3P) provides groundwater storage anomalies (GWSA) from a cross-cutting combination of GRACE/GRACE-FO-based terrestrial water storage (TWS) and storage compartments of the water cycle (WSCs) that are part of the Copernicus portfolio. The data set comprises gridded anomalies of groundwater, TWS, and the WSCs glacier, snow, soil moisture and surface water bodies plus layers containing uncertainty information for the individual data products. All WSCs are spatially filtered with a Gaussian filter to be compatible with TWS. Spatial coverage is global, except Greenland and Antarctica, with 0.5-degree resolution. Temporal coverage is from April 2002 to September 2023 with monthly temporal resolution. Gridded data sets are available as NetCDF files containing variables for the parameter value as anomaly in mm equivalent water height and the parameter’s uncertainty as mm equivalent water height. The latest version of the data is visualized at the GravIS portal: https://gravis.gfz-potsdam.de/gws. From GravIS, the data is also available as area averages for several large river basins and aquifers, as well as for climatically similar regions. G3P was funded by the EU Horizon 2020 programme in response to the call LC-SPACE-04-EO-2019-2020 “Copernicus evolution – Research activities in support of cross-cutting applications between Copernicus services” under grant agreement No. 870353. --------------------------------------------------------------------------------------------- Version History: 10 March 2023: Release of Version v1.11. That version is the initial release of the data (Güntner et al., 2023; https://doi.org/10.5880/G3P.2023.001) (DATE TO BE ADDED) Release of Version v1.12. Temporal coverage has been extended until September 2023.

HUST-Grace2024: GRACE and GRACE Follow-On monthly gravity field solution

The new time series of GRACE and GRACE-FO monthly solution HUST-Grace2024 is recently developed at Huazhong University of Science and Technology. During retrieving our model, the reprocessed GRACE L1b RL03 data and GRACE-FO RL04 data are used, and the newly de-aliasing product AOD1B RL07 is applied. In addition, a hybrid processing chain is applied to improve the quality of final solutions. Further details are presented in Zhou et al. (2024). This work is supported by the National Natural Science Foundation of China (No. 42074018, 41931074, 42061134007).

WHU-SWPU-GOGR2022S: A combined gravity model of GOCE and GRACE

WHU-SWPU-GOGR2022S is a static gravity field model complete to spherical harmonic degree and order of 300 by combining GOCE and GRACE normal equations. Details of the processing procedures are as follows: (1) Details of the GOCE processing procedures: (1a) Input data: -- GOCE SGG data: EGG_NOM_2 (GGT: Vxx, Vyy, Vzz and Vxz) in GRF (9/10/2009-20/10/2013) -- GOCE SST data: SST_PKI_2, SST_PCV_2, SST_PRD_2 (9/10/2009-20/10/2013) -- Attitude: EGG_NOM_2 (IAQ), SST_PRM_2 (PRM) -- Non-conservative force: Common mode ACC (GG_CCD_1i) -- Background model: tidal model (solid etc.), third-body acceleration, relativistic corrections, ... (1b) Data progress strategies: -- Data preprocessing - Gross outlier elimination and interpolation (only for the data gaps less than 40s). - Splitting data into subsections for gaps > 40s -- The normal equation from SST data - Point-wise acceleration approach (PAA) - Extended Differentiation Filter (low-pass) - Max degree: up to 130 - Data: PKI, PCV, CCD -- The normal equation from SGG data - Direct LS method - Max degree: up to 300 - Data: GGT, PRD, IAQ, PRM - Band-pass filter: used to deal with colored-noise of GGT observations (pass band 0.005-0.100Hz ) - Forming the normal equations according to subsections - Spherical harmonic base function transformation instead of transforming GGT from GRF to LNRF -- Combination of SGG and SST - Max degree: up to 300 - The VCE technique is used to estimate the relative weights for Vxx, Vyy, Vzz and Vxz - Tikhonov Regularization Technique (TRT) is only applied to near (zonal) terms (m<20, n<=200) and high degree terms (n>200) - Strictly inverse the normal matrix based on OpenMP (2) Details of the GRACE processing procedures: (2a) Input data: -- GRACE L1B (JPL) data products: GNV1B RL02, ACC1B RL02, SCA1B RL03 and KBR1B RL03 -- AOD1B RL06 (GFZ) de-aliasing product -- Data period: 04/2002-05/2017 (2b) Data preprocessing: -- Splitting data of SCA1B into subsections for gaps > 120s and interpolation with polynomial for gaps <= 120s -- Splitting data of ACC1B into subsections for gaps > 5s and interpolation with polynomial for gaps <= 5s -- Gross outlier elimination ACC1B with a moving window of length 10 min, and interpolation with polynomial -- Pre-calibration of ACC1B with a-priori bias and scale Parameters provided by GRACE TN-02 (2c) Calculation method: - dynamic approach - numerical integrator: 8th-order Gauss-Jackson integrator - integrator step: 5 seconds - arc length: 24 hours (2d) Combination - GNV1B and KBR1B are combined with their a-priori precision, i.e. 2cm of GNV1B and 2um/s of KBR1B - The normal equations of different months are combined with variance components estimation (2e) Force models: - Earth's static gravity field: GGM05s up to d/o 180 - Solid earth tides: IERS 2010 - Ocean tides: FES2014b up to d/o 180 - Solid Earth pole tide: IERS 2010 - Ocean pole tide: Desai 2002 up to d/o 180 - N-body Perturbation: the Sun and Moon with JPL DE421 - atmospheric tides: Bode and Biancale model - AOD1B product: AOD1B RL06 model up to d/o 180 - General Relativistic effects: Schwarzschild terms of IERS 2010

Global Gravity-based Groundwater Product (G3P)

The Global Gravity-based Groundwater Product (G3P) provides groundwater storage anomalies (GWSA) from a cross-cutting combination of GRACE/GRACE-FO-based terrestrial water storage (TWS) and storage compartments of the water cycle (WSCs) that are part of the Copernicus portfolio. The data set comprises gridded anomalies of groundwater, TWS, and the WSCs glacier, snow, soil moisture and surface water bodies plus layers containing uncertainty information for the individual data products. All WSCs are spatially filtered with a Gaussian filter to be compatible with TWS. Spatial coverage is global, except Greenland and Antarctica, with 0.5-degree resolution. Temporal coverage is from April 2002 to December 2020 with monthly temporal resolution. Gridded data sets are available as NetCDF files containing variables for the parameter value as anomaly in mm equivalent water height and the parameter’s uncertainty as mm equivalent water height. The latest version of the data is visualized at the GravIS portal: https://gravis.gfz-potsdam.de/gws. From GravIS, the data is also available as area averages for several large river basins and aquifers, as well as for climatically similar regions. G3P was funded by the EU Horizon 2020 programme in response to the call LC-SPACE-04-EO-2019-2020 “Copernicus evolution – Research activities in support of cross-cutting applications between Copernicus services” under grant agreement No. 870353. --------------------------------------------------------------------------------------------- Version History: 10 March 2023: Release of Version v1.11. This is the initial release of the data.

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