STAR Joint Polar Satellite System Algorithms & Data Products website National Oceanographic & Atmospheric Administration website NOAA Center for Satellite Applications and Research website
Suomi NPP VIIRS Snow Cover, 3/29/2016 - click to enlarge

Suomi NPP VIIRS Snow Cover, 3/29/2016 - click to enlarge

Snow Cover

Team Lead: Jeff Key

Product Description

The Snow Cover is the horizontal and vertical extent of snow cover. The snow cover product contains two products: a binary snow cover (BSC) mask and a fractional snow cover (FSC). The binary snow cover snow/no-snow mask provides a mapping of snow covered areas as either containing or not having snow. The fractional snow cover is defined as the fraction of a given area of the earth's horizontal surface that is covered by snow as seen from the satellite ("viewable" snow fraction). The fractional snow cover does not account for the snow masked by vegetation.

Binary Snow Cover:

  • Analogous to MODIS SnowMap algorithm
  • Decision-tree threshold-based classification approach
  • Uses NDSI, NDVI, reflectance, temperature (VIIRS bands I1,I2,I3, I5)
  • Output: Binary snow/no-snow map at 375 m resolution

Snow Cover Fraction:

  • IDPS Snow Fraction: Based on aggregated 2x2 binary snow retrievals
  • Enterprise (NDE) Snow Fraction: Two algorithms implemented
    • NDSI-based: MODIS heritage algorithm, used up to Collection 5; Adopted as the primary algorithm for JPSS
    • Visible reflectance-based: Uses VIIRS band I1 reflectance; Algorithm used with GOES Imager and AVHRR; Approach similar to GOES-R
  • Output: "Viewable" snow fraction at 750m resolution (IDPS), 375m for JPSS-1

Both Binary Snow Cover Mask and Snow Cover Fraction products are clear-sky daytime-only land products

Product and Data Access

Products and data:

EDR Long Term-Monitoring

Documentation

Snow Cover (binary mask) (IDPS and NDE)
Snow Fraction (IDPS and NDE)

Users

NCEP, River Forecast Center, National Ice Center (NIC), National Snow Ice Data Center (NSIDC), National Operational Hydrological Remote Sensing Center (NOHRSC), NWS

Further Enhancements

Binary Snow:

  • Develop and implement an improved snow cover climatology
  • Account for angular anisotropy of NDSI, NDVI, Reflectance

Fraction of Snow Cover:

  • Incorporate shadows as class, multi-endmember retrievals
  • True (not "viewable") snow fraction - Need to account for snow masking by forests