Diagram: Arctic sea ice extent since 1972
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Arctic sea ice extent (total area of at least 15% ice concentration) since 1972.

Diagram: Antarctic sea ice extent since 1972
Click on the image to enlarge.

Antarctic sea ice extent (total area of at least 15% ice concentration) since 1972.

Diagram: Arctic sea ice extent since 1979
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Annual Arctic sea ice extent (total area of at least 15% ice concentration) for selected years since 1979.

Diagram: Antarctic sea ice extent since 1979
Click on the image to enlarge.

Annual Antarctic sea ice extent (total area of at least 15% ice concentration) for selected years since 1979.

Diagram: Arctic sea ice extent during previous 7 years
Click on the image to enlarge.

Annual Arctic sea ice extent (total area of at least 15% ice concentration) for the last 7 years.

Diagram: Antarctic sea ice extent during previous 7 years
Click on the image to enlarge.

Annual Antarctic sea ice extent (total area of at least 15% ice concentration) for the last 7 years.

Time Series Of Sea Ice Extent

To adapt data from a newer source to the data from an older source, the newer data were linearly transformed such that both mean and standard deviation or the newer time series matched the mean and standard deviation of the older time series in the overlap period.

In addition, the data are smoothed by a 5-day running mean. Consequently, the current day and the day before are only averaged over three respectively four days and might still vary slightly for two (resp. one) days

Since July 3, 2012, AMSR2 data is displayed which is adapted with the same parameters as its predecessor AMSR-E. The fit parameters are not deduced by comparing it during an overlap period to another time series. Hence, the data ought to be treated with caution until confirmation by independent sources.

The diagrams show sea ice extent data since 1979. The complete time series is composed of observations from different sensors, using different sea ice concentration retrieval algorithms and adaptations to each other using certain overlap periods: (1): Merged ESMR, SMMR, and SSM/I-SSMIS Sea Ice Extent from NSIDC (2): See information on this data set at NSIDC
# Period Algorithm Sensor, Frequencies, Source Adapted to Overlap period
1. 1972 - 2002 NASA Team SMMR & SSM/I, 19 and 37 GHz from NSIDC(1) #2. 1989 - 2002
2. Oct 26, 1978 - Dec 2010 NASA Team Sea ice concentrations from NIMBUS-7 SMMR and DMSP SSM/I-SSMIS passive microwave data, 19 and 37 GHz, from NSIDC(2) reference only, but not part of the time series because of some gaps 1978 - 1988
3. 2003 - Oct 4, 2011 ASI AMSR-E, 89 GHz #2. 2002 - 2007
4. Oct 5, 2011 -Jul 2, 2012 ASI SSMIS F-17, 91 GHz #3. Sep 2010 – Sep 2011 (using SSMIS F-17 data)
5. Jul 3, 2012 to date ASI AMSR2, 89 GHz #3. (same fit parameters used) Jul 3, 2012 to date

Time Series Data

Text files containing the total sea ice extent in the northern hemisphere can be found here and for the southern hemisphere here

More data can be found in the Data Archive. To quickly browse datasets, please have a look at the Data Browser.

How to cite

Please help maintaining this service by properly citing and acknowledging if you use the data for publications:
Spreen, G., L. Kaleschke, and G.Heygster(2008), Sea ice remote sensing using AMSR-E 89 GHz channels J. Geophys. Res.,vol. 113, C02S03, doi:10.1029/2005JC003384.

Contact

For questions regarding the data please contact Gunnar SpreenChristian Melsheimer, or Georg Heygster.
For questions related to the website and data-browser please contact Malte Gerken.

Institute of Environmental Physics, University of Bremen, Germany.