The National Snow and Ice Data Center (NSIDC) (described in the October 2, 1998 Scout Report) provides the Sea Ice Concentrations from Nimbus-7 SMMR and DMSP SSM/I Passive Microwave Data set. The dataset ranges from October 1978 to December 1996 and includes "daily and monthly averaged sea ice concentrations in binary and .gif format derived from Nimbus-7 SMMR and DMSP SSM/I F8, F11, and F13 daily brightness temperatures at a grid cell size of 25 X 25 km." Summaries of these sea ice concentrations datasets are also available.