Blue Marble View
The monthly Sea Ice Index provides a quick look at Arctic-wide changes in sea ice. It is a source for consistently processed ice extent and concentration images and data values since 1979. Monthly images show sea ice extent with an outline of the 30-year (1981-2010) median extent for that month (magenta line). Other monthly images show sea ice concentration and anomalies and trends in concentration.
Monthly Sea Ice Extent Anomaly Graph
This graph shows monthly ice extent anomalies plotted as a time series of percent difference between the extent for the month in question and the mean for that month based on the January 1981 to December 2010 data. The anomaly data points are plotted as plus signs and the trend line is plotted with a dashed grey line.
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The daily Sea Ice Index provides a quick look at Arctic-wide changes in sea ice. It provides consistently processed daily ice extent and concentration images and data since 1979. Daily extent images show ice extent at concentrations greater than 15% for a given day with an outline of the typical extent for that day based on a 30-year (1981-2010) median (orange line).
Daily Sea Ice Extent Time Series
This graph provides a snapshot of changes in ice extent for the last four months. The graph shows a time series for the Northern hemisphere (solid blue line). The graph also includes a comparison line for the 1981 through 2010 average (solid grey line) that is plotted for the previous four months as well as the upcoming month. The light gray area around the 1981-2010 average line shows the two standard deviation range of the data. The graph also includes lines for selected earlier years, for comparison (dashed green line).
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