Recent summer Arctic atmospheric circulation anomalies in a historical perspective

摘要: Abstract. A significant increase in the summertime occurrence of a high pressure area over Beaufort Sea, Canadian Arctic Archipelago, and Greenland has been observed since beginning 2000s, particularly between 2007 2012. These circulation anomalies are likely partly responsible for enhanced ice sheet melt as well sea loss 2007. Therefore, it is interesting to analyse whether similar conditions might have happened late 19th century region. We used an atmospheric type classification based on daily mean level 500 hPa geopotential height data from five reanalysis sets (ERA-Interim, ERA-40, NCEP/NCAR, ERA-20C, 20CRv2) put recent perspective with variability 1871. found that 2007–2012 occurred past, despite higher uncertainty reconstructed before 1940. For example, only ERA-20C shows could explain 1920–1930 warming, contrast 20CRv2. While exceed by factor 2 interannual region, their origin (natural or global warming) remains debatable.