Retrieval of snow grain size and albedo of western Himalayan snow cover using satellite data

摘要

In the present study we describe the retrievals of snow grain size andspectral albedo (plane and spherical albedo) for western Himalayan snowcover using Hyperion sensor data. The asymptotic radiative transfer (ART)theory was explored for the snow retrievals. To make the methodologyoperational only five spectral bands (440, 500, 1050, 1240 and 1650 nm) ofHyperion were used for snow parameters retrieval. The bi-spectral method(440 nm in the visible and 1050/1240 nm in the NIR region) was used toretrieve snow grain size. Spectral albedos were retrieved using satellitereflectances and estimated grain size. A good agreement was observed betweenretrieved snow parameters and ground observed snow-meteorologicalconditions. The satellite retrieved grain sizes were compared with fieldspectroradiometer retrieved grain sizes and close results were found forlower Himalayan snow. The wavelength 1240 nm was found to be more suitablecompared to 1050 nm for grain size retrieval along the steep slopes. Themethodology was able to retrieve the spatial variations in snow parametersin different parts of western Himalaya which are due to snow climatic andterrain conditions of Himalaya. This methodology is of importance foroperational snow cover and glacier monitoring in Himalayan region usingspace-borne and air-borne sensors.