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NASA Distributed Active Archive Center (DAAC) at NSIDC

Sea Ice Trends and Climatologies from SMMR and SSM/I-SSMIS

Data from Defense Meteorological Satellite Program (DMSP) Sensors

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 January 1979 through current processing. The data are derived from the NASA Team Sea Ice Concentrations from Nimbus-7 SMMR and DMSP SSM/I-SSMIS Passive Microwave Data. A threshold of 15 percent concentration is applied to the monthly climatology fields.

Data Access

Data are available via FTP.

Data Format

Data are in flat binary one-byte integer format. Thus, 97 means 97 percent sea ice concentration. For the Northern Hemisphere, the grid size is 304 x 448 pixels; and for the Southern Hemisphere, the grid size is 316 x 332 pixels. Corresponding PNG images of monthly climatologies are also provided in the browse directory on the FTP site.

File Naming Convention

The data files are named according to the following convention, and as described in Table 1:

mean.mmm.yyyy1-yyyy2.h

where:

Table 1. File Naming Convention Description
Variable Description
mean Identifies this as a mean ice concentration percentage data file
mmm 3-character month
yyyy1 4-digit year of the first year for which data was available
yyyy2 4-digit year of the last year for which data was available
h Hemisphere (n: Northern, s: Southern)

Help Topics

For instructions on importing these data into ArcGIS, and other help topics for this data set, see our NSIDC User Services Online Support.