[M-IS08] Global climate change driven by the Southern Ocean and the Antarctic Ice Sheet

[MIS08-P02] Separation of Antarctic Ice Sheet Variation Components Using Satellite Gravimetry and Satellite Altimetry Data

*Keiko Yamamoto¹, Jun'ichi Okuno², Yoshiya Irie², Tianyan Shi², Koichiro Doi², Yoichi Fukuda² (1.National Astronomical Observatory of Japan, 2.National Institute of Polar Research)

Keywords:Anatarctica, ice sheet mass balance, satellite gravity mission, satellite altimetry

The use of satellite gravimetry data for the study of ice sheet balance in Antarctica has the advantage to detect temporal variations in large-scale ice sheets as changes in mass. Gravity measurement satellites observe the changes in vertical mass integration. To obtain ice sheet mass variation in Antarctica, it is necessary to remove the effect of mass changes due to glacial isostatic adjustment (GIA). In our previous studies, we used satellite altimetry data in addition to satellite gravimetry data and tried to separate the ice sheet mass variations from the GIA mass change. The results show that assuming the observed elevation changes can be explained solely by surface firn change, there will be regions where the estimated GIA values are negative. It is unnatural, and thus, this suggests that the Antarctic ice sheet mass balance cannot be fully explained only by the surface snow and ice variations.
In this study, we estimated each component of the ice sheet variations assuming that the existing each GIA model value is true. As estimated parameters, we newly considered the components of basal melt and ice-sheet flow beneath the surface ice sheet, in addition to surface firn. They were estimated by the least-squares method from the satellite gravity data and satellite altimeter data after removing the GIA component. We finally compared the results with the ice sheet model to assess whether they could be explained within the uncertainty of the GIA model and the error of the ice sheet model for each region.