On Monday, 11 July from 3:00 p.m. through Wednesday, 13 July until 5:00 p.m. (USA Mountain Time), NSIDC data distribution, services, and Web site will be unavailable to accommodate a major upgrade to our data center. We apologize for any inconvenience this may cause you. Need to talk to us? You can always contact our friendly User Services Office at email@example.com or + 1 303.492.6199.
If a pixel in MODIS bands 2 and 4 has an NDSI value greater than or equal to 0.4 and the reflectance in bands 2 and 4 is greater than 0.10 (as shown by the cross-hatched rectangle), it is mapped as snow.
A separate group of criteria tests is used to better detect snow in vegetated regions. If the value of NDSI and NDVI of a pixel falls in the region indicated by the left polygon, it is mapped as snow.