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On the relevance of aerosols to snow cover variability over High Mountain Asia
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  • Chayan Roychoudhury,
  • Cenlin He,
  • Rajesh Kumar,
  • John M. McKinnon,
  • Avelino F. Arellano Jr.
Chayan Roychoudhury
University of Arizona

Corresponding Author:[email protected]

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Cenlin He
National Center for Atmospheric Research
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Rajesh Kumar
National Center for Atmospheric Research (UCAR)
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John M. McKinnon
University of Arizona
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Avelino F. Arellano Jr.
University of Arizona
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Abstract

While meteorology and aerosols are identified as key drivers of snow cover variability in High Mountain Asia (HMA), complex non-linear interactions between them are not adequately quantified. Here, we attempt to unravel these interactions through a simple relative importance (RI) analysis of meteorological and aerosol variables from ERA5/CAMS-EAC4 reanalysis against satellite-derived snow cover from MODIS across 2003-2018. Our results show a statistically significant 7% rise in the RI of aerosol-meteorology interactions (AMI) in modulating snow cover during late snowmelt season (June-July), notably over low snow-covered (LSC) regions. Sensitivity tests further reveal that the importance of meteorological interactions with individual aerosol species are more prominent than total aerosols over LSC regions. We find that the RI of AMI for LSC regions is clearly dominated by carbonaceous aerosols, on top of the expected importance of dynamic meteorology. These findings clearly highlight the need to consider AMI in hydrometeorological monitoring, modeling, and reanalyses.