Ice area and extent time series: SSM/I derived¶
The sea ice data presented here were derived from satellite passive-microwave radiometers, specifically, the Scanning Multichannel Microwave Radiometer (SMMR) on NASA’s Nimbus 7 satellite, for November 1978-August 1987, a sequence of Special Sensor Microwave Imagers (SSMIs) on the F8, F11, and F13 satellites of the Defense Meteorological Satellite Program (DMSP), for August 1987-December 2007, and the Special Sensor Microwave Imager Sounder (SSMIS) on the DMSP F17 satellite for January 2008-December 2012. The baseline data used were daily maps of sea ice concentration. The maps are polar stereographic projections with individual grid elements of approximately 25 km x 25 km; and the ice concentration data are also archived at the National Snow and Ice Data Center (NSIDC) at http://nsidc.org. The concentrations are calculated for each ocean grid element and are used to derive ‘sea ice extent’, which is calculated as the sum of all ocean elements having a sea ice concentration of at least 15%, and ‘sea ice area’, which is calculated as the sum over all ocean grid elements of the product of ice concentration and grid element area. The data sets provided here include the hemispheric totals and additionally the values for nine regions in the Arctic and five regions in the Antarctic. These regions are identified in Figures 1 and 2 respectively. Figures 3 and 4 provide plots of the trends in the Arctic and Antarctic sea ice extents, along with monthly deviations and 12-month running means. The monthly deviations are calculated by taking the individual month’s ice extent/area and subtracting from it the average over the course of the data set of the extents/areas for that month.
NASA data are not copyrighted; however, when you publish our data or results derived therefrom, we request that you include an acknowledgment within the text of the publication and reference list. Data Citation and Acknowledgements