On Friday, 06 November 2015 from 8:00 a.m. to 5:00 p.m. (USA Mountain Time), our FTP services, which also includes automated data requests from services such as Polaris and the GLAS Subsetter, will be unavailable because of system maintenance. We apologize for any inconvenience this may cause you.
Figure 2. Graph showing classification of pixels for summer forest, snow-covered forest field, and winter forest, from Normalized Difference Snow Index (NDSI) and Normalized Difference Vegetation Index (NDVI). From Klein, Hall, and Riggs (1998).