Snow / Cloud Discrimination

The figure below depicts a GOES-based three-color technique which distinguishes low (water) clouds and fog, from high (ice) clouds, from snow cover in a satellite image. Areas of low clouds/fog are white, high/ice clouds are magenta, and snow cover on the ground is red. The major area of snow (red) in this image resides in the Canadian provinces north of Minnesota, which can be contrasted with the ice-based cloud (magenta) over much of north central U.S. The product is second-order product, with first-order products computed from GOES visible, shortwave, and longwave spectral bands, and then those products are combined to produce this second-order three-color product which discriminates between different cloud and ground-cover types.

The figure below shows an example how high spatial resolution MODIS snow cover imagery is improved via cirrus filtering using the 1.38 mm band.