Future Atmospheric Rivers in Antarctica : intensity and impacts

Atmospheric rivers (ARs) are extreme hydrological events that have strong impacts on the Antarctic surface mass balance (SMB), through both snow accumulation and surface melt due to heating and rain. To estimate their impacts on future SMB, we study Antarctic ARs in an ensemble of 21st century simulations. While the number of detected ARs increases continuously when using a constant detection threshold based on historical moisture fluxes, it remains stable with an adaptive threshold evolving with the rising background moisture. However, ARs penetrate further into Antarctica following a wave number 3 pattern. In addition, the intensity of Antarctic ARs, measured by moisture fluxes, is simulated to increase following the Clausius-Clapeyron relation. The opposing SMB impacts become larger, with both increasing snowfall, and coastal surface melt and rainfall. Yet, their overall influence on the SMB is dominated by increased snow accumulation.