The Bootstrap Sea Ice Concentrations from Nimbus-7 SMMR and DMSP SSM/I-SSMIS, Version 3 data set, available through the NASA National Snow and Ice Data Center Distributed Active Archive Center (NSIDC DAAC), has been updated through 31 December 2020. This data set consists of daily and monthly sea ice concentrations derived from brightness temperature measurements. This data set is available for the north and south polar regions, with a temporal coverage extending back to 26 October 1978. The data are gridded to the 25 km polar stereographic projection and provided in two-byte integer format.
Data set DOI: https://doi.org/10.5067/7Q8HCCWS4I0R