Cryospheric products from the DMSP-SSM/I: status and research applications

Abstract

The DMSP Special Sensor Microwave Imager (SSM/I) was launched on 19 June 1987. This first operational passive microwave radiometer operates at four wavelengths (0.35–1.55 cm) with vertical and horizontal polarization for three of the channels. The orbit provides global coverage except for a small polar gap and 12 hour repeat coverage in high latitudes. A Cryospheric Data Management System (CDMS) for snow and ice products developed by the NASA Ocean Data System (NODS) and the National Snow and Ice Data Center (NSIDC) for NASA Polar Oceans Program extracts polar SSM/I data and makes them available in suitable formats for scientific users. The design of the CDMS at NSIDC has evolved since the initial planning in 1984 to one relying on CD-ROM technology for data distribution. The SSM/I data, and the earlier 7-year SMMR data (re-binned to the SSM/I grid), are available as brightness temperatures averaged daily for each channel/polarization in a polar stereographic 25 km grid for both polar regions and as gridded 3-day average total sea ice concentrations and multiyear ice fractions based on the NASA Team algorithm. The availability of a passive microwave record of sea ice parameters since 1978 in a directly comparable format greatly facilitates their research use. The polar regions are of considerable importance in studies of global climate change in view of snow and ice/albedo feedback processes that contribute to the high latitude amplification of such changes. Related climate-cryosphere research includes studies to validate the algorithm employed to prepare the ice products, on ice/climate processes, and on temporal trends in sea ice.