We present the scatterometer-derived snowmelt and freeze variability data for three river basins in the Indian Himalayas (the third pole)—knowledge about which is important for studying the climate and water resources of the area. We document the timing and duration of snowmelt/freeze across the Indian Himalayas. The analysis includes data from QuikSCAT (2000 to 2009), Oceansat Scatterometer (OSCAT) (2010 to 2013), Advanced Scatterometer (ASCAT) (2014 to 2016), and SCATSAT (2017). We utilize Ku-band HH-polarized data from QuikSCAT, OSCAT, and SCATSAT and C-band VV-polarized data from ASCAT and use the adaptive/variable threshold method based on winter mean and standard deviation. The analysis is based on the sensitivity of the backscatter coefficient to the presence of liquid water content in the snow caused due to melting. Past air temperature data available for seven Himalayan stations are used to validate the methodology. The melt/freeze detection is limited to areas where snow is available in that year. The majority of melt onset in the study area takes place in April. Melt onset for higher-elevation zones for the Indus, Ganges, and Brahmaputra basins varies from April 19 to May 20, April 17 to April 30, and April 7 to April 28, respectively. Major freeze onset for these basins is in October. The outputs generated from the analysis will be available on Bhuvan portal under the National Information System for Climate and Environment Studies program of Indian Space Research Organisation. |
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Cited by 5 scholarly publications.