NSIDC has a new Arctic sea ice data set from NASA’s Making Earth System Data Records for Use in Research Environments (MEaSUREs) program: MEaSUREs Arctic Sea Ice Characterization 25 km EASE-Grid 2.0.
This data set, derived from passive microwave brightness temperatures, offers users daily Arctic sea ice locations, sea ice age, day of melt onset, and status of melt onset for the years 1979 through 2012. The data are gridded in the 25 km Equal-Area Scalable Earth Grid (EASE-Grid) 2.0 and provided as netCDF files.
To get the data visit http://nsidc.org/data/nsidc-0532/. Complete documentation is available at http://www.nsidc.org/data/docs/measures/nsidc-0532/index.html.