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Keywords:

  • Snow covered area;
  • Snow water equivalent;
  • Remote sensing;
  • Passive microwave;
  • Afghanistan;
  • Hydrology

Abstract

Since the winter season of 2004–2005, annual snow assessments have been conducted for the major watersheds of Afghanistan using multispectral (AVHRR and MODIS) and passive microwave (SSM/I and AMSR-E) remote sensing technologies. Because of limited ground-based observations of precipitation and snow pack conditions, remote sensing provides a unique opportunity to assess these conditions at different scales offering an appraisal of current conditions from a historical context. This paper describes the methodology that has been developed over the past seven winter seasons, wherein bi-weekly snow products and assessments are produced including the following: current snow-covered area (SCA) at regional and watershed scales; estimation of SCA by elevation band; current snowpack volume [snow water equivalent (SWE)] for each watershed with a historical perspective (1987–present); snow condition outlook by watershed; general summary of snow conditions based on remote sensing products and limited ground-based observations; and if warranted, a snow melt flooding advisory. Further analysis of these snow products and assessments are presented. Moreover, comparisons between both available passive microwave estimates of SWE (SSM/I and AMSR-E) for all watersheds differ in magnitude yet exhibit similar historical trends. The SSM/I versus AMSR-E historical differences in SWE for each of the major Afghanistan watersheds are quantified and show a strong relationship (R2 = 96%) to the mean elevation of the watershed. Copyright © 2012 John Wiley & Sons, Ltd.