The European Space Agency (ESA) Global Snow Monitoring for Climate Research (GlobSnow) snow water equivalent (SWE) v2.0 data record contains snow information derived for the Northern Hemisphere since 1979 to present day. The snow water equivalent describes the amount of liquid water in the snow pack that would be formed if the snow pack was completely melted. The data record is produced using a combination of passive microwave radiometer and ground-based weather station data. The SWE record is produced on a daily, weekly, and monthly basis. SWE information is provided for terrestrial non-mountainous regions of the Northern Hemisphere, excluding glaciers and ice sheets. The data are provided in HDF4 and NetCDF formats along with PNG browser images for quick viewing. A single file contains the data for a single day and contains two fields: the SWE estimate and an error estimate (standard deviation). The GlobSnow SWE record, based on methodology by Pulliainen (Pulliainen 2006 and Takala et al. 2011), utilizes a data-assimilation based approach combining space-borne passive radiometer data (SMMR, SSM/I, and SSMIS) with data from ground-based synoptic weather stations. The satellite sensors utilized provide data at K- and Ka-bands (19 GHz and 37 GHz, respectively) at a spatial resolution of approximately 25 km. The SWE product is projected to Equal-Area Scalable Earth Grid (EASE-Grid) and provides the daily SWE estimates for whole Northern Hemisphere (lambert's equal-area azimuthal projection) in a single file. Although the EASE-Grid projection can represent data almost to the equator, the product is limited between latitudes 35° and 85° for physical reasons (extent of seasonal snow cover). The input satellite data for the SWE prototype products are from SMMR, SSM/I, and SSMIS sensors acquired from National Snow and Ice Data Center, Boulder Colorado, U.S.A. (NSIDC). The snow water equivalent product is based on the combination of satellite-based microwave radiometer and ground-based weather station data.

• The long term SWE data set spans from 1979 – to present day
• The SWE maps are produced as daily, weekly, and monthly composites
• Nimbus-7 SMMR, DMSP (F8/F11/F13) SSM/I, and DMSP F17 SSMIS are the main data sources: SMMR for 1979 - 1987; SSM/I for 1987 - 2009, SSMIS for 2010 - present
• Coverage: Non-mountainous of Northern Hemisphere, excluding glaciers and ice sheets
• The SWE maps are generated using EASE-Grid projection and a 25km spatial resolution
More detailed descriptions are found within the project documentation accessible through the project Web pages.