Fram Strait spring ice export and September Arctic sea ice

Abstract

Abstract. The Arctic Basin exports ~ 10 % of the sea ice area southwards annually through Fram Strait. A larger than normal export decreases the remaining mean thickness and ice area. A new updated timeseries from 1979–2013 of Fram Strait sea ice area export shows an overall increase until today, and that more than 1 million km2 has been exported annually in recent years. The new timeseries has been constructed from high resolution radar satellite imagery of sea ice drift across 79° N from 2004–2013, regressed on the observed cross-strait surface pressure difference, and shows an increasing trend of 7 % per decade. The trend is caused by higher southward ice drift speeds due to stronger southward geostrophic winds, largely explained by increasing surface pressure on Greenland. Spring and summer area export increases more (~ 14 % per decade) than in autumn and winter, and these export anomalies have a large influence on the following September mean ice extent.