PRELIMINARY: This global Level-2 (L2) data set provides daily snow cover detected using Normalized Difference Snow Index (NDSI) and a series of screens designed to alleviate errors and flag uncertain snow cover detections. The NDSI is derived from radiance data acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS) on board the Aqua satellite: DOI:10.5067/MODIS/MYD02HKM.061 and DOI:10.5067/MODIS/MYD021KM.061. Each data granule contains 5 minutes of swath data observed at a resolution of 500 m.

The terms "Version 61" and "Collection 6.1" are used interchangeably in reference to this release of MODIS data.