National Snow and Ice Data Center

nsidc-g02135

Sea Ice Index

Version 3.

<p style="color: red; font-weight: bold;">Notice: On 5 August 2015, a problem arose with the F17 DMSP satellite that provides data to generate these images that led to bad/missing data. The F17 satellite is now back to normal operation. NSIDC is in the process of removing the bad data, and will be monitoring the incoming F17 data stream.</p> 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 and data values from November 1978 to the present. Sea Ice Index images depict ice cover and trends in ice cover in the Arctic and Antarctic oceans. Sea Ice Index data files tabulate ice extent in numbers. 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. Monthly images show sea ice extent with an outline of the median extent for that month for comparison. Other monthly images show sea ice concentration as well as trends in concentration for that month. Monthly extent products are also available as geographic information systems (GIS) compatible shapefiles. Plain ASCII text data files contain monthly mean extent and area, in millions of square kilometers, by year. These monthly extent numbers are used for graphs of extent anomalies with trend lines and significance intervals. Anomalies and median extent are calculated using a 30-year reference period of 1981 through 2010. Daily images show sea ice extent, with an outline of the median extent for that day for comparison, and sea ice concentration. Plain ASCII text data files contain daily extent, in millions of square kilometers, for almost every day from 1978 onward. These daily extent numbers are used for graphs of daily extent over the last four months.

http://nsidc.org/data/G02135

Identified by : G02135

This dataset was released on December 05, 2002.

The time range for this dataset starts at January 01, 1979.

The spatial range for this dataset is -90° to -39.23° latitude, and -180° to 180° longitude. map (center)

This dataset uses data from an instance of the special-sensor-microwave-imager-sounder instrument on the defense-meteorological-satellite-program-f-17 platform.

Provenance

This dataset was derived from dataset Sea Ice Concentrations from Nimbus-7 SMMR and DMSP SSM/I-SSMIS Passive Microwave Data using the activity nsidc-g02135-seaice-index-processing

• 4 arrays were derived from this dataset : array 520ef000 (37x2), array a30515f8 (39x2), array cbf5f43d (40x5), array ab1aac2b (41x2)
• 2 figures were derived from this dataset : figure nca3 2.29, figure nca3 2.28
• 10 images were derived from this dataset : image 65878d6c, image c1e21a9b, image c90fb657, image 22409ee9, image 6e8f6a92, image 1612f573, image 572e9f3a, image cccb9639, image 049cbd6d, image 093b83a0

This work is referenced by:

• Climate Science Special Report: The Fourth National Climate Assessment: Volume I (reference)
• chapter 11 (reference)
• figure 11.1 (reference)
• Impacts, Risks, and Adaptation in the United States: The Fourth National Climate Assessment, Volume II (reference)
• Climate Change Impacts in the United States: The Third National Climate Assessment (reference)
• chapter 22 (reference)
• figure 22.2 (reference)

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DOI : 10.7265/N5QJ7F7W
Also known as :

• identifier c4d4180a-1c6a-458b-ae4e-d0f8e2820e3b (datagov lexicon)
• dataset sea-ice-index (datagov lexicon)
• dataset oai:nsidc/G02135 (nsidc lexicon)