New Refined Observations of Climate Change from Spaceborne Gravity Missions (NEROGRAV)

A deep understanding of mass distribution and mass transport in System Earth is needed to answer central questions in hydrology, oceanography, glaciology, geophysics and climate research. The necessary information is primarily derived from satellite mission data as observed by GRACE (Gravity Recovery and Climate Experiment) and GRACE-FO (Follow-on) describing the gravity field of the Earth and its temporal variations.

The research group (RG) „New Refined Observations of Climate Change from Spaceborne Gravity Missions (NEROGRAV)”, funded by the German Research Foundation (DFG), develops since May 2019 new analysis methods and modeling approaches to improve GRACE and GRACE-FO mission data analysis and focuses on geophysical applications that benefit from significantly reduced error levels in the time series of monthly gravity fields. Phase 1 lasted from May 2019 till April 2022. After successful evaluation in January 2022 we will start the second phase in January 2023.  

The central hypothesis of the research group, slightly updated for phase 2, is therefore: Only by concurrently improving and better understanding of sensor data, background models, and processing strategies of satellite gravimetry, the resolution, accuracy, and long-term consistency of mass transport series can be significantly increased; the science return in various fields of application improved and the potential of future technological sensor developments fully exploited.

In order to reach this overarching goal, the RG in particular concentrates on four different objectives:

1. Improvement and error quantification of geophysical background models,
2. Improvement of spatial-temporal parameterizations,
3. Validation of improved background models and gravity field models against independent data, and
4. Synthesis of results and recommendations for NGGMs (phase 1) and Novel geophysical applications and provision of recommendations for NGGMs (phase 2), respectively

which were elaborated in six Individual Projects (IP) in phase 1:

• IP 1: Improved Tidal Dynamics and Uncertainty Estimation for Satellite Gravimetry (TIDUS; PIs: Maik Thomas (FU Berlin), Denise Dettmering (DGFI - TU Munich))
• IP 2: Next Generation Non-tidal Atmospheric and Oceanic De-aliasing Models (NAODEMO; PI: Henryk Dobslaw (GFZ))
• IP 3: High-Resolution Atmospheric-hydrological Background Modelling for GRACE/GRACE-FO – regional refinement and validation (HIRABAM; PIs: Petra Friederichs, Jürgen Kusche, Andreas Hense, Michael Schindelegger (University Bonn))
• IP 4: Optimized Space-Time Parameterization for GRACE and GRACE-FO data Analysis (OSTPAGA; PIs: Roland Pail (TU Munich), Frank Flechtner (TU Berlin (Spokesman of RG))
• IP 5: Improved Stochastic Modeling in GRACE/GRACE-FO Real data processing (ISTORE; PI: Rolf König (GFZ))
• IP 6: Post-process Techniques, Impact on NGGM And Recommendations (POTINAR; PI: Roland Pail (TU Munich))

and will be continued starting in January 2023 in phase 2:

• IP 1: Improved Tidal Dynamics and Uncertainty Estimation for Satellite Gravimetry (TIDUS-2; PIs: Maik Thomas (FU Berlin), Denise Dettmering (DGFI – TU Munich))
• IP 2: Atlantic Meridional Overturning Circulation: Inferences from Satellite Gravimetry and Numerical Ocean Models (AMOCING; PIs: Henryk Dobslaw (GFZ), Michael Schindelegger (University Bonn))
• IP 3: High-Resolution Atmospheric-hydrological Background Modelling for GRACE/GRACE-FO – regional refinement and validation (HIRABAM-2; PIs: Petra Friederichs and Jürgen Kusche (University Bonn))
• IP 4: Near-real time, Long-term, LRI and SLR combination aspects (NELOS; PIs: Natalia Panafidina (GFZ), Thomas Gruber (TU Munich))
• IP 5: Optimized Space-Time Parameterization for GRACE and GRACE-FO data Analysis (OSTPAGA-2; PIs: Roland Pail (TU Munich), Frank Flechtner (TU Berlin (Spokesman of RG))
• IP 6: Climate Signals from GRACE/GRACE-FO and Next Generation Gravity Missions (CLISGY; PIs: Annette Eicker (HCU Hamburg), Roland Pail (TU Munich))

The final data products of the different phase 1 IPs will be made available in fall 2022.

Please follow the link on the left hand side. Final results of phase 2 are planned for spring 2026.