These sea ice concentrations have been generated by applying the NASA Team algorithm to DMSP F8 SSM/I brightness temperature observations from 19 GHz (vertical and horizontal), 37- and 22 GHz vertical frequencies, calculating two gradients for use as weather filters. Global coverage is provided, but sea ice concentrations are only derived for ocean, ice, and possible ice surfaces poleward of 35 degrees latitude, from 01 August 1987 through 30 November 1988. In the Northern Hemisphere, where data are not filtered due to weather effects, first-year and multi-year concentrations (in percent) are calculated; total ice concentration is taken as the sum of these two. Only total ice is calculated for the Southern Hemisphere. All 25 km swath data are in HDF.
As of 26 September 2019, this data set is retired and no longer available for download. The data set is being retired because other passive microwave data sets with longer temporal records are available at NSIDC. Two possible alternatives are the Sea Ice Concentrations from Nimbus-7 SMMR and DMSP SSM/I-SSMIS Passive Microwave Data, Version 1 data set or the NOAA/NSIDC Climate Data Record of Passive Microwave Sea Ice Concentration, Version 3 data set.