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Abstract:
Surface mass balance (SMB) is an essential component of ice sheet mass balance. But its impacts on sea level rise during the past decades are uncertain, primarily due to the spatial heterogeneity of net precipitation, especially in West Antarctica. Meanwhile, Pacific SST and Atlantic SST have experienced long-term changes over the past decades. In the Pacific Ocean, the Interdecadal Pacific Oscillation (IPO) turns to a negative phase in the late 1990s, while in the North Atlantic Ocean, SST has been widely increasing until today. An increasing number of studies demonstrate how these changes affect surface temperature, sea ice, and ice shelf in West Antarctica through their impacts on Amundsen Sea Low (ASL). Here, we highlight that the decadal trend of Pacific and Atlantic SST significantly contribute to the long-term change in West Antarctica during 1980-2010. SMB observation from ice cores is compared with the net precipitation from the fifth generation of European Centre for Medium-Range Weather Forecasts (ERA-5), a state-of-art reanalysis dataset. The period is selected as 1980-2010, because only a few ice cores data can be found after that and the reanalysis dataset is only reliable after that. To test if the change in the Pacific and Atlantic Ocean’s SST affects the spatial heterogeneity trend of SMB in West Antarctica, we perform two experiments using Community Atmosphere Model version 5 (CAM5). Modeling results show similar patterns as the statistic analysis in ERA5.