This data set contains gridded brightness temperatures and sea ice concentrations for both polar regions. It spans the period from October 1978 through August 1987, when the Nimbus-7 SMMR scanner was turned off. The data were collected every other day at 6.60, 10.69, 18.00, 21.00 and 37.00 GHz. Due to spacecraft power limitations, the scanner operated only on alternate days. There are usually at ... least foutreen days of coverage per month, although major data gaps occurred during the month of August. In August 1982, the following days are missing for both polar regions: 4th, 8th, and 16th; in August 1984, the 13th through the 23rd are missing for both polar regions; and in August 1985, the 6th through 8th are missing for the Southern Hemisphere. Brightness temperature and sea ice concentration grids have 25 x 25 km grid elements in polar stereographic projection. Volume 7 contains all SMMR sea ice concentrations for both polar regions, plus five months of brightness temperature grids for the North polar region. Brightness temperature grids are stored as 16-bit integers, one day of brightness temperature data is 0.27 mbytes for the North polar region, 0.21 mbytes for the South. Ice grids are stored as 8-bit integers. Files contain 136192 bytes and 104912 bytes for the North and South respectively. The NASA Team Algorithm (Cavalieri et al. 1984, Gloersen and Cavalieri 1986) was used to calculate ice concentrations from the brightness temperatures. The data were produced by Dr. P. Gloersen, NASA/GSFC, Oceans and Ice Branch, and are available via FTP. Notice to Data Users: SMMR TCT tapes comprised the input data set, unlike the SMMR Digital Media product distributed by NSIDC in 1979.
Laboratory for Hydrospheric Processes
NASA/Goddard Space Flight Center
Province or State:
Carsey, F.D., ed., Microwave remote sensing of sea ice. Geophysical Monograph 68, American Geophysical Union, 1992. Cavalieri, D.J., P. Gloersen and W.J. Campbell, Determination of sea ice parameters with the Nimbus-7 SMMR, J. Geophys. Res. 89(D4):5355-5369, 1984. Comiso, J.C. and H.J. Zwally, Polar microwave brightness temperatures from Nimbus-7 SMMR: Time series of daily and monthly maps from ... 1978 to 1987. NASA. Reference Publication, 1223, 82 p.,1989. Francis, E.A., Calibration of the Nimbus-7 Scanning Multichannel Microwave Radiometer (SMMR), 1979-1984, Oregon State University, M.S. thesis, 248 p., 1987. Gloersen, P., In-orbit calibration adjustment of the Nimbus-7 SMMR. NASA Technical Memorandum 100678, 39 p, 1987. Gloersen, P. and D.J. Cavalieri, Reduction of weather effects in the calculation of sea ice concentration from microwave radiances. J. of Geophys. Res. 91(C3):3913-3919, 1986. Gloersen, P., W.J. Campbell, D.J. Cavalieri, J.C. Comiso, C.L. Parkinson and H.J. Zwally. Arctic and Antarctic Sea Ice, 1978-1987: Satellite Passive Microwave Observations. NASA SP-511, 1992. National Snow and Ice Data Center, Nimbus-7 SMMR Polar Radiances and Sea Ice Concentrations on CD-ROM. User's Guide. NSIDC, Special Publication NSIDC SP-3, Boulder, CO, 1994. Nimbus-7 User's Guide. NASA, Goddard Space Flight Center, 263 p., 1978.