title: Spatially mapped reductions in the length of the Arctic sea ice season.
abstract: Satellite data are used to determine the number of days having sea ice coverage in each year 1979-2013 and to map the trends in these ice-season lengths. Over the majority of the Arctic seasonal sea ice zone, the ice season shortened at an average rate of at least 5 days/decade between 1979 and 2013, and in a small area in the northeastern Barents Sea the rate of shortening reached over 65 days/decade. The only substantial non-coastal area with lengthening sea ice seasons is the Bering Sea, where the ice season lengthened by 5-15 days/decade. Over the Arctic as a whole, the area with ice seasons shortened by at least 5 days/decade is 12.4 × 106km2, while the area with ice seasons lengthened by at least 5 days/decade is only 1.1 × 106km2. The contrast is even greater, percentage-wise, for higher rates.
  
  
  CONCLUSIONS
  Sea ice seasons have shortened by at least 5 days/decade over most of the ArcticAcross 1.9 million km2ice seasons have shortened by at least 25 days/decadeCounter to most of the Arctic ice seasons have lengthened in the Bering Sea.
authors.affiliation: Cryospheric Sciences Laboratory, NASA Goddard Space Flight Center Greenbelt, Maryland, USA.
authors.forename: Claire L
authors.initials: CL
authors.lastname: Parkinson
keywords: Arctic; climate change; sea ice
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