Attribution of recent changes in autumn cyclone associated precipitation in the Arctic
An Arctic Ocean with less sea ice and more open water in September has led to anomalous warming of the overlying atmosphere in autumn. Through influences on column water vapour and atmospheric circulation, it is reasonable to expect that this warming will have impacts on Arctic precipitation. Analysis of data from the JRA‐25 atmospheric reanalysis reveals an autumn increase in cyclone‐associated precipitation over the past decade. This is linked to a shift in atmospheric circulation towards more frequent and more intense cyclones in the Atlantic sector of the Arctic. Composites based on years with the five lowest and five highest September ice extents reveal more autumn cyclone associated precipitation and column water vapour during low ice years than during high ice years. However, difficulties in establishing cause and effect, including the absence of a clear association between spatial patterns of recent precipitation changes and ice extent anomalies, lead us to conclude that attribution of recent autumn precipitation increases to reduced ice cover is premature.
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Document Type: Research Article
Affiliations: National Snow and Ice Data Center, Cooperative Institute for Research in Environmental Science, Campus Box 449, University of Colorado, Boulder CO 80309-0449, USA
Publication date: August 1, 2011