Data Set ID:

Sea Ice Index, Version 3

The Sea Ice Index provides a quick look at Arctic- and Antarctic-wide changes in sea ice. It is a source for consistent, up-to-date sea ice extent and concentration images, in PNG format, and data values, in GeoTIFF and ASCII text files, from November 1978 to the present. Sea Ice Index images also depict trends and anomalies in ice cover calculated using a 30-year reference period of 1981 through 2010.

The images and data are produced in a consistent way that makes the Index time-series appropriate for use when looking at long-term trends in sea ice cover. Both monthly and daily products are available. However, monthly products are better to use for long-term trend analysis because errors in the daily product tend to be averaged out in the monthly product and because day-to-day variations are often the result of short-term weather.

This is the most recent version of these data.

Version Summary:

Updated the method used to calculate the monthly average sea ice extent and area data values.

COMPREHENSIVE Level of Service

Data: Data integrity and usability verified; data customization services available for select data

Documentation: Key metadata and comprehensive user guide available

User Support: Assistance with data access and usage; guidance on use of data in tools and data customization services

See All Level of Service Details

Data Format(s):
  • PNG
  • GeoTIFF
  • CSV
  • Shapefile
Spatial Coverage:
N: 90, 
N: -39.23, 
S: 30.98, 
S: -90, 
E: 180, 
E: 180, 
W: -180
W: -180
Platform(s):DMSP, DMSP 5D-3/F17, DMSP 5D-3/F18, Nimbus-7
Spatial Resolution:
  • 25 km x 25 km
Sensor(s):SMMR, SSM/I, SSMIS
Temporal Coverage:
  • 26 October 1978
(updated daily)
Temporal Resolution1 dayMetadata XML:View Metadata Record
Data Contributor(s):Florence Fetterer, Kenneth Knowles, Walter Meier, Matthew Savoie, Ann Windnagel

Geographic Coverage

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As a condition of using these data, you must cite the use of this data set using the following citation. For more information, see our Use and Copyright Web page.

Fetterer, F., K. Knowles, W. N. Meier, M. Savoie, and A. K. Windnagel. 2017, updated daily. Sea Ice Index, Version 3. [Indicate subset used]. Boulder, Colorado USA. NSIDC: National Snow and Ice Data Center. doi: [Date Accessed].

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Descriptions of and Differences between the NASA Team and Bootstrap Algorithms
NSIDC currently archives passive microwave sea ice concentration products based on two algorithms: the NASA Team algorithm and the Bootstrap algorithm. Both algorithms were developed by researchers at the NASA Goddard Space Flight Center in the 1980s. Provided below are two short summaries of the... read more
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Are the same regions used in the Sea Ice Index and MASIE-NH?
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