The sea ice data derived from AMSR-E using the ARTIST sea ice (ASI) algorithm offer a factor of 4 finer spatial resolution than most sea ice data sets from passive microwave satellite instruments. ASI is based on the difference of vertically and horizontally polarized brightness temperatures at 89 GHz; this difference is independent of temperature but depends on emissivity; ice differences are small while water exhibits a large polarization difference. ASI obtains intermediate concentrations by interpolation between these end-member signatures (tie-points). A drawback of ASI is that higher frequencies are sensitive to weather. Nonetheless, the ASI includes adjustments intended to correct for weather using the lower-frequency channels. The AMSR-E satellite died in October, 2011. The AMSR-2 was launched in early 2012, and data are available as of 2013. U Bremen also offers daily sea ice estimates based on the 91 GHz channel of the SSMIS. There are no uncertainty estimates with the data sets, and it is not yet known how merging the AMSR-E, SSMIS and AMSR-2 data impacts apparent climate trends. Version 5.6i is the most recent processing.
The data from the Integrated Climate Data Center at Hamburg are a more recent processing (L. Kaleschke, personal communication, 2012). Description.
Bremen HDF files: v5
ICDC netCDF files: v5.6i.
Figure 1 on this page is from the ICDC v5.6i
Spreen, G., L. Kaleschke, and G.Heygster(2008), Sea ice remote sensing using AMSR-E 89 GHz channels J. Geophys. Res.,vol. 113, C02S03, doi:10.1029/2005JC003384.
the data from Hamburg: Spreen, G., and L. Kaleschke (2008), "AMSR-E ASI 6.25 km Sea Ice Concentration Data, V5.5", Institute of Oceanography, University of Hamburg, Germany, digital media (ftp-projects.zmaw.de/seaice/).
National Center for Atmospheric Research Staff (Eds). Last modified 20 Aug 2013. "The Climate Data Guide: Sea Ice Concentration data from AMSR-E, AMSR2 & SSMIS, U Bremen and U Hamburg ASI algorithm." Retrieved from https://climatedataguide.ucar.edu/climate-data/sea-ice-concentration-data-amsr-e-amsr2-ssmis-u-bremen-and-u-hamburg-asi-algorithm.