Notice Regarding Data Updates and Corrections
28 July 2014
Reprocessing is complete and updated data are now available through 31 December 2013 for all Sea Ice Trends and Sea Ice Trends and Climatologies from SMMR and SSM/I-SSMIS data sets.
04 September 2013
Reprocessing is complete and updated data are now available through 31 December 2012 for all Sea Ice Trends and Sea Ice Trends and Climatologies from SMMR and SSM/I-SSMIS data sets. With this update, the following changes have been implemented:
Total Ice-Covered Area and Extent
- The cutoff value which defines a region as ice-covered or not ice-covered has been adjusted from 14.8 percent to 15 percent to more closely match the methodology used to calculate other sea ice extent and area products at NSIDC.
Ice Persistence and Monthly Climatology of Sea Ice Concentration (Monthly Means)
- Includes the new 15 percent cutoff value described above.
- To prevent inconsistencies between different algorithms, these parameters are now calculated exclusively using the NASA team algorithm.
Monthly Ocean Masks and Maximum Extent Masks
- The ocean mask files and maximum extent mask files have been temporarily removed as they are not the masks used in the production of these data sets. NSIDC is currently standardizing masks across all sea ice products and will distribute the replacement masks as soon as they are available.
This most recent reprocessing also rectifies two previous releases of these data sets that contained erroneous data. In January/February of 2012, and May of 2013, the products were to have contained data from 2007 to 2010 and from 2010 to 2011, respectively. However, the climatology products contained data only through 2007. We recommend replacing previously downloaded 2010 and 2011 climatology data files with the climatology files that now extend through 2012. The Total Ice-Covered Area and Extent data set did contain post-2007 data, but reprocessed data utilizing the new methodology are available in the 2012 release.
For more information or help with these data sets, please contact NSIDC User Services.
This Web page describes the different types of Sea Ice Trends and Climatologies that NSIDC provides. The products are derived from the Scanning Multichannel Microwave Radiometer (SMMR), the Special Sensor Microwave/Imager (SSM/I), and the Special Sensor Microwave Imager/Sounder (SSMIS). They are divided into the following categories:
- Total Ice-Covered Area and Extent: Daily and monthly total ice-covered area and extent products.
- Ice Persistence: Monthly climatologies of ice persistence provide information on how frequently ice occurs in a region during a given month over the time period of the data.
- Monthly Climatology of Sea Ice Concentration: Monthly sea ice concentration climatology data represent mean ice concentration
percentages for each month over the entire time period of the data.
- Monthly Ocean Masks and Maximum Extent Masks: Monthly and maximum extent ocean masks showing the sea ice extent during a particular month or for the entire time period of the data.