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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 (WA) using daily output from RACMO2 model and reanalysis data (1979-2016). Empirical Orthogonal Function analysis of geopotential height anomalies (at 850 hPa) reveals that the dominant drivers of atmospheric variability over WA are the Southern Annular mode (SAM), PSA-patterns associated with Amundsen Sea low (ASL) and El Nin˜o-Southern Oscillation (ENSO), and atmospheric rivers (ARs). Overall, 93.7% of days with extreme precipitation at the 2 coastal stations of ASE are associated with these patterns. ASL is the main driver of extreme precipitation over ASE (associated with 44.75% of extreme precipitation days) followed by PSA-1/ENSO (22.16%), ARs (21.1%) and SAM (12%). ASL is the main driver of extreme precipitation in all seasons except summer when ARs are dominant. Extreme precipitation linked to ASL and ARs are more intense (by ∼ 2 mm/day) than the rest.