Reconciling ocean mass change and GIA from satellite gravity and altimetry (OMCG-2)
The OMCG project has two key objectives,
- Resolve conflicting mass/steric sea level budget partitioning. This is most important for the South-East Asian Island States region with current rates of up to 12 mm/a.
- Provide consolidated and consistent gridded OMC to the SPP and to the community. Address harmonizing the GRACE/GRACE-FO OMC estimates by available bridging solutions.
With these objectives, we believe the project to be instrumental for any integrated analysis of climate-related sea-level change at global to regional scale. It supports the central objective of the SPP and provides key data sets for many other SPP-projects.
To reach our objectives within the project, we will work on the following main challenges:
- Express the 'Direct' and 'Inverse' approaches in a joint theoretical framework to understand their differences and their equivalences.
- Investigate 'Direct' and 'Inverse' approaches in a joint comprehensive consistent simulation.
- Resolve GIA together with OMC and the ice sheet contribution to OMC by integrating satellite altimetry over the ice sheets as an additional observable. This will reduce the GIA-related uncertainty of present-day OMC. The implied improvement of ice sheet change estimates will aid the understanding of ice sheet mass balance and ice-ocean-solid Earth interaction and will thereby aid OMC predictions.
- Assess real-data results, disseminate them within and beyond the SPP.
The Bonn and Dresden groups will collaborate to develop a common theoretical framework for assessing various approaches and the resulting performance for OMC. Further both groups will collaborate to integrate, at different levels, the information from ice altimetry together with firn modeling into the global inversion framework, in order to improve the estimation of GIA.
OMCG-2 will seek to directly quantify physical processes that contribute to sea-level change and trends at the global but also regional scale, including ice-ocean-land processes (GIA) and land-ocean processes (contribution of terrestrial water storage change). OMCG-2 will thus provide important data sets for modelling projects inside and outside the SPP. In addition, OMCG-2 will provide regionalized data for Northern Europe and South east Asia regions and this will be helpful for improving predictions and assessments of sea-level rise effects at regional scale.
Willen, M.O., T. Broerse, A. Groh, B. Wouters, P Kuipers Munneke, M. Horwath, M.R. van den Broeke, and L. Schröder (2021), Separating Long-Term and Short-Term Mass Changes of Antarctic Ice Drainage Basins: A Coupled State Space Analysis of Satellite Observations and Model Products, JGR Earth Surface, vol. 126, doi:10.1029/2020JF005966.