Author(s): Gunnar Spreen; Sebastian Gerland; Edmond Hansen
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Abstract: Arctic sea ice has become significantly thinner during the first decade of the 21st century [e. g., Haas et al., 2008; Kwok and Rothrock, 2009; Vaughan et al., 2013], with concurrent changes in age composition toward more first-year ice (sea ice of not more than one winter growth) at the expense of old ice (sea ice that has survived at least one summer melt season) [e. g., Comiso, 2012; Vaughan et al., 2013]. We examine 24 years (1990–2013) of monthly ice thickness distributions from the Transpolar Drift in Fram Strait, as observed by upward looking sonars (ULS) moored on the seabed. An extensive discussion of this time series for 1990–2011 can be found in Hansen et al. (2013) and the reader is referred to that manuscript for more detailed information. The update presented here now also covers the two record low summer Arctic sea ice extend years 2007 and 2012. Fram Strait, located between northeast Greenland and Svalbard, is the only deep connection between the Arctic Basin and other oceans and is the main export gate for sea ice. The mooring location in Fram Strait is well suited for long-term monitoring of Arctic sea ice thickness, due to the steady advection of ice through the strait from many sites across the Arctic Ocean. Ice thickness observed here represents an integrated signal of the time varying state of the ice cover in the mayor part of the Arctic Ocean that deliver ice to the Transpolar Drift and Fram Strait.
Year: 2014