Jet stream changes cause climatically exceptional Greenland Ice Sheet melt
http://www.shef.ac.uk/news/nr/jet-stream-greenland-ice-sheet-melt-1.280360[font face=Serif]17 June 2013
[font size=5]Jet stream changes cause climatically exceptional Greenland Ice Sheet melt[/font]
[font size=4]Research from the University of Sheffield has shown that unusual changes in atmospheric jet stream circulation caused the exceptional surface melt of the Greenland Ice Sheet (GrIS) in summer 2012.[/font]
[font size=3]An international team led by Professor Edward Hanna from the University of Sheffields Department of Geography used a computer model simulation (called SnowModel) and satellite data to confirm a record surface melting of the GrIS for at least the last 50 years - when on 11 July 2012, more than 90 percent of the ice-sheet surface melted. This far exceeded the previous surface melt extent record of 52 percent in 2010.
The team also analysed weather station data from on top of and around the GrIS, largely collected by the Danish Meteorological Institute but also by US programmes, which showed that several new high Greenland temperature records were set in summer 2012.
The research, published today in the International Journal of Climatology, clearly demonstrates that the record surface melting of the GrIS was mainly caused by highly unusual atmospheric circulation and jet stream changes, which were also responsible for last summer's unusually wet weather in England.
The analysis shows that ocean temperatures and Arctic sea-ice cover were relatively unimportant factors in causing the extra Greenland melt.
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http://dx.doi.org/10.1002/joc.3743