Arctic/Antarctic Sea Ice Time Series

Arctic/Antarctic Sea Ice Time Series

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.

Following Figure 4 there are links to plots of the monthly ice extents, monthly ice extent deviations, yearly ice extents, and seasonal ice extents for the Northern Hemisphere and each of the nine Northern Hemisphere regions identified in Figure 1, and for the Southern Hemisphere and each of the five Southern Hemisphere regions identified in Figure 2. These links are followed by a similar set of links for ice area (versus ice extent) plots. The plots cover the period November 1978 – December 2013.

Details regarding the calculations can be found in Cavalieri et al. (1999) and Cavalieri et al. (2012). Results for the Arctic can be found in Parkinson et al. (1999) and Cavalieri and Parkinson (2012), and results for the Antarctic can be found in Zwally et al. (2002) and Parkinson and Cavalieri (2012). These cover shorter time periods than the updated plots presented here but present many more details about the results.

References:

Cavalieri, D. J., C. L. Parkinson, P. Gloersen, J. C. Comiso, and H. J. Zwally, 1999: Deriving long-term time series of sea ice cover from satellite passive-microwave multisensor data sets, Journal of Geophysical Research, 104(C7), 15,803-15,814.

Cavalieri, D. J., C. L. Parkinson, N. DiGirolamo, and A. Ivanoff, Intersensor calibration between F13 SSMI and F17 SSMIS for global sea ice data records, IEEE Geosci. Remote Sensing Letters, 9 (2), 233-236, 10.1109/LGRS.2011.2166754, March 2012.

Cavalieri, D. J., and C. L. Parkinson, 2012: Arctic sea ice variability and trends, 1979-2010, The Cryosphere, 6, 881-889, doi:10.5194/tc-6-881-2012.

Parkinson, C. L., D. J. Cavalieri, P. Gloersen, H. J. Zwally, and J. C. Comiso, 1999: Arctic sea ice extents, areas, and trends, 1978-1996, Journal of Geophysical Research, 104(C9), 20,837-20,856.

Parkinson, C. L., and D. J. Cavalieri, 2012: Antarctic sea ice variability and trends, 1979-2010, The Cryosphere, 6, 871-880, doi:10.5194/tc-6-871-2012.

Zwally, H. J., J. C. Comiso, C. L. Parkinson, D. J. Cavalieri, and P. Gloersen, 2002: Variability of Antarctic sea ice 1979-1998, Journal of Geophysical Research, 107(C5), 3041, doi:10.1029/2000JC000733, 21 pp.