Antarctic and Greenland Ice Sheet Gravimetric Mass Balance from GRACE(-FO): TU Dresden’s ESA CCI+ Products and Component Partitioning for Antarctica

Abstract

For more than two decades, the Gravity Recovery and Climate Experiment (GRACE) and its follow-on mission GRACE-FO have been providing unique information on mass changes occurring globally and in the Antarctic (AIS) and Greenland (GIS) ice sheets particularly. Ice sheets were assigned by the Global Climate Observing System (GCOS) as one of the essential climate variables. GRACE(-FO) observations showed that both AIS and GIS have an accelerating ice mass loss. Moreover, ice sheets are considered as one of the largest sources of uncertainty in future global sea-level rise projections. Therefore, consistent analysis of the ice sheet mass changes is needed for improving the understanding of their contribution to the global sea-level rise.We present the recently published extension (through December 2025) of the gravimetric mass balance (GMB) gridded and drainage basins products by TU Dresden for the AIS and GIS that was done in the framework of the European Space Agency's (ESA) Climate Change Initiative (CCI) projects. The products are based on the monthly GRACE(-FO) solutions CSR RL06.3 by the Center for Space Research at the University of Texas at Austin with applied tailored sensitivity kernel approach, developed at TU Dresden (Groh and Horwath 2021). For Antarctica a novelty of this release is a gap-filling interpolation for the 11-months GRACE/GRACE-FO transition period using the Regional Atmospheric Climate Model RACMO2.4p1. For the investigated period of more than 23 years, the GMB of the AIS was quantified to be −83±44 Gt a-1 and for GIS −246±14 Gt a-1, that corresponds to a mean sea-level rise of 0.23±0.12 mm a-1 and −0.68±0.04 mm a-1 respectively.The total mass change observed by GRACE(-FO) is the combined effect of variations in surface mass balance (SMB) changing ice-flow dynamics. The Partitioned GMB (GMBP) product is being developed to reflect these two physically distinct components. SMB variation effects are predominantly short-term or interannual and are controlled by ice-atmosphere interaction. Ice-flow dynamics effects, in contrast, are mostly long-term (decadal or longer), controlled by ice-ocean interaction and most crucial for understanding long-term evolution of the ice sheet. We present preliminary methods and results of the Partitioned GMB.