Examining the Influence of Tropical Pacific Sea-Surface Temperatures on Annual Surface Mass Balance in West Antarctica

The climatological mechanisms influencing surface mass balance (SMB) on the West Antarctic Ice Sheet (WAIS) are highly varied and complex. Rapid warming in recent decades has made constraining the mechanisms that affect SMB in this region increasingly important to future projections of ice sheet mass balance and sea level rise. The Amundsen Sea Low (ASL) has perhaps one of the largest effects in shaping the local climate of WAIS, and thereby SMB, but the influences of other large-scale phenomena are less well understood. In particular, the effect of tropical Pacific sea-surface temperatures (SST) on SMB in the region is still poorly constrained. It is generally accepted that the El Niño Southern Oscillation (ENSO), a measure of SST variability in the tropical Pacific, influences the climate of West Antarctica, but by what mechanisms and to what degree are more difficult to quantify. In this study, we determine the potential relationship between tropical Pacific SST, variability in atmospheric pressure and wind vectors around WAIS, and anomalously high and low SMB. In order to assess these relationships, we use satellite observations of SST, SMB estimates from ice and firn cores in interior West Antarctica, and atmospheric variables from ERA-Interim Reanalysis. We focus on recent decades, 1980-2010, a period where there is significant overlap in available data from all sources. Preliminary results show that the relationship between tropical Pacific SST and SMB varies somewhat with ice core location. However, in general, annual mean SST in the tropical Pacific are negatively (positively) correlated with anomalously high (low) SMB in West Antarctica across the suite of ice cores. We also show anomalous patterns in both atmospheric pressure and wind vectors in the vicinity of WAIS associated with these anomalous SMB years. Finally, we aim to determine the physical mechanisms, if any, linking these anomalous atmospheric conditions around WAIS to the tropical Pacific SST. This research helps us better understand climatic drivers of annual SMB variability in a region where climate change and decreasing total mass balance are of concern.