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Fig2.1.4.8-1: General bias of ice thickness from LIM2.  The scale is in m.  Red too thick, blue too thin.  The averages hide a lot of features and the bias in ice thickness in LIM2 is not uniform.

Sea ice extent 

The climate location of the ice edge is based on a near 30year periods but the area of winter ice cover has been reduced over recent years.  Maximum area of antarctic sea ice in the southern winters in 2023 and 2024 (not shown) are also lower than the available 46-year satellite records.  The climate of ice cover, particularly during recent years, is probably generally too great in extent.   This can have an impact on forecast temperatures and the derivation of Extreme Forecast Index in polar regions.

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Fig2.1.4.8-2: Sea ice concentration in early January 2025 compared with the Median ice edge over the period 1981-2010 (orange line).  Observed arctic sea ice extent is taken from Sea Ice Today from the National Snow and Ice Center (NSIDC) at University of Colorado Boulder.   

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Fig2.1.4.8-3: Observed arctic sea ice extent has become less than the general extent during previous years.  Over recent years the extent of ice has been less than the median winter extent.

Ice charts

The extent of ice cover is shown with different thresholds on Opencharts and ecCharts..

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