Relative Contribution of Atmospheric Drivers to “Extreme” Snowfall Over the Amundsen Sea Embayment

Abstract

AbstractWe investigate the atmospheric drivers of extreme precipitation over the Amundsen Sea Embayment (ASE) of West Antarctica (WA) using daily output from the RACMO2 model and reanalysis data (1979–2016). Overall, 93.7% of days with extreme precipitation at the two coastal stations of ASE are associated with the four dominant Empirical Orthogonal Function (EOF) modes of geopotential height anomalies (at 850 hPa) over WA. The second EOF mode, associated with a coupled pattern consisting of an Amundsen Sea Low and a blocking high to the east, is the main driver of extreme precipitation over ASE, linked to 44.75% of extreme precipitation days. This is followed by EOF‐3 (associated with El Niño Southern Oscillation/PSA‐1), EOF‐4 (likely associated with more frequent “atmospheric river” events), and EOF‐1 (i.e., Southern Annular mode) with a contribution of 22.16%, 21.1%, and 12%, respectively. Extreme precipitation linked to EOF‐2 and EOF‐4 is more intense (by ∼2 mm/day) than the rest.