This directory contains daily snow and ice maps generated by the extended Global Multisensor Automated Snow and Ice Mapping System (eGMASI)
as well as derived monthly, annual and multiyear mean snow and ice cover maps.


The daily product includes the original GMASI snow and ice maps complemented with snow depth and snow water equivalent estimates. Daily maps cover the time period from 1987 to current. They are produced on a geographical (latitude-longitude) grid with 0.04 deg (or about 4 km at the equator) grid cell size. The product is offered in NetCDF format


Monthly products include maps of monthly snow cover amd ice cover occurrence for every month of each year from July 1987 to current. Yearly products incorporate maps of annual snow and ice cover duration. Multiyear mean products include maps of snow and ice cover duration as well as maps of the mean date of snow cover onset and melt off.


Daily snow and ice cover maps are derived from combined observations in the optical bands of AVHRR sensor onboard METOP satellites and passive microwave observations from DMSP SSMIS. Snow depth and snow water equivalent is estimated using combined passive microwave and in situ snow depth observations. All retrieval algorithms are fully automated. 


Maps of Snow/Ice Cover become available on the next day, maps of Snow Depth and of Snow Water Equivalent typically become available at a delay of 5-6 days.
Reduced and full resolution imagery can be viewed at https://www.star.nesdis.noaa.gov/smcd/emb/snow/gmasi/


This project was supported by NOAA Weather Program Office (WPO), grant No. NA21OAR4590368, 2021-2024.

For questions or comments related to the product: peter.romanov@noaa.gov (Peter Romanov)