A Comparison of WorldView and MODIS in Detecting Fractional Snow Cover over High Mountain Asia

Snow in High Mountain Asia (HMA) significantly contributes to the water resources that millions depend upon downstream; thus, the need to understand how snow patterns in this region are changing is essential. However, locally monitoring snow in the HMA region can be challenging: the high elevation, rugged terrain, and lack of infrastructure make some areas nearly inaccessible and difficult to collect data. The use of consistently collected satellite data, therefore, is the preferred method for monitoring snow cover across this vast region. Recent analysis of spatially and temporally complete MODIS Snow Covered Area and Grain Size (MODSCAG) fractional snow covered area (fSCA) has shown trends toward fewer snow covered days in some HMA regions over the MODIS record. Although the skill of MODSCAG to classify snow cover has been established, the spatially and temporally complete products are relatively new. Here, we provide an initial assessment of the spatially and temporally complete fSCA using high resolution imagery from DigitalGlobe's WorldView 2 and 3 satellites, which have a much higher spatial resolution (~1 m visible) relative to MODIS (500 m). We selected four regions of interest spanning the HKH from east to west, and focus the assessment at the snow line and lower elevations, where change in snow duration is primarily occurring.