A snow index for the Landsat Thematic Mapper and Moderate Resolution Imaging Spectroradiometer

Abstract

Describes the snow mapping algorithm being developed for use with the Earth Observing System (EOS) MODerate resolution Imaging Spectroradiometer (MODIS). A key component of this snow mapping algorithm is the normalized difference snow index (NDSI). The NDSI employs Landsat Thematic Mapper (TM) visible (0.56 /spl mu/m) and near-infrared (1.65 /spl mu/m) data. The snow algorithm uses the NDSI in combination with near-infrared reflectance to identify snow cover and discriminate snow from clouds. The NDSI-based snow algorithm functions with a simple set of decision rules for snow, and can be run in an automated fashion on any TM scene without a priori knowledge of surface characteristics. Consistent identification of snow cover in a variety of TM scenes has been attained with the algorithm. Snow mapping results from TM imagery of the Glacier National Park, Montana region are presented. This algorithm is expected to generate global snow cover data products in the EOS era beginning in 1998. >