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Relative contribution of atmospheric drivers to ‘extreme’ snowfall over the Amundsen Sea Embayment
  • Pranab Deb,
  • Sai Prabala Swetha Chittella
Pranab Deb
Indian Institute of Technology Kharagpur, Indian Institute of Technology Kharagpur

Corresponding Author:[email protected]

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Sai Prabala Swetha Chittella
Indian Institute of Technology Kharagpur, Indian Institute of Technology Kharagpur
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Abstract

We investigate the atmospheric drivers of extreme precipitation over the Amundsen Sea Embayment (ASE) of West Antarctica using daily output from RACMO2 model and re- analysis data (1979-2016). Overall, 93.7% of days with extreme precipitation at the 2 coastal stations of ASE are associated with the 4 dominant Empirical Orthogonal Function (EOF) modes of geopotential height anomalies (at 850 hPa) over West Antarctica. The second EOF mode, associated with a coupled pattern consisting of 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 are more intense (by ∼2 mm/day) than the rest.