Author(s): Wei Lixin; Ting Qin; Timo Vihma; Bin Cheng
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Keywords: No Keywords
Abstract: The cyclone activity plays a very important role in the Arctic climate system. Cyclones are closely linked with precipitation, atmospheric moisture budget and sea ice distribution. In this study, cyclones entering the Arctic Ocean (cross into north of 70oN from south) are investigated in the context of climate change and variability. A cyclone tracking scheme of the University of Reading was applied. The scheme can be divided into three parts: re-processing (filtering), detecting and tracking. We used this scheme to construct cyclone tracks from the 6 hourly ERA Interim reanalyses for the period of 1979–2012. The results suggested that the cyclone activity has a slightly decreasing trend in spring and summer, but an increasing trend in autumn. In general, the cyclones are stronger in winter than in summer. In spring, more cyclones enter the Arctic from the North Atlantic sector, especially from the Greenland Sea and Norwegian Sea. In summer, the cyclones in the Pacific sector, in particular in the East Siberian Sea, are more numerous than in the Atlantic sector. In autumn, the cyclones occurrences in the Atlantic sector are more numerous than summer. 90% of summer cyclones have a central pressure ranging from 980 to 1010 hPa, but in winter the range is much wider, from 930 to 1015 hPa. 75–85% of cyclones last for 1–7 days, and 20–30% of cyclones have a lifetime of 1–2 days. Cyclones with a lifetime more than 14 days are more common in summer than other seasons. The singular value decomposition (SVD) method suggested that the cyclone activity is closely connected with sea ice concentration in summer.
Year: 2014