Teleconnection drivers for Antarctic atmospheric rivers in E3SMv2 and CESM2
Atmospheric rivers (ARs) stretching into Antarctica are not as common as their mid-latitude counterparts, but are almost always consequential in their ice sheet impacts. ARs are long, meandering, and efficient vehicles of moisture transport originating from lower latitudes, even as far as the tropics. They explain much of the interannual variability of precipitation across the ice sheet, and can either contribute to, or deplete from, the surface mass balance. Thus, understanding the sources of predictability for Antarctic ARs are not only important for prediction on weather and seasonal scales, they are also key to understanding long-term Antarctic climate. Here, we analyze climate change ensemble simulations from E3SMv2 and CESM2 and diagnose the relationships between ARs, modes of variability (MOVs), and their respective teleconnections. It is these relationships that potentially inform AR predictability on both weather and climate timescales. Although the Southern Annular Mode (SAM) explains the vast majority of variability around all of Antarctica, its imprint on Antarctic ARs is complex, regionally dependent, and often not significant. The Pacific South American (PSA) Mode 2 and the Indian Ocean Dipole appear to hold the most sway for West Antarctica and East Antarctica, respectively.