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Advances in Meteorology
Volume 2013 (2013), Article ID 170387, 11 pages
http://dx.doi.org/10.1155/2013/170387
Research Article

Trends and Variability of North Pacific Polar Lows

Institute of Coastal Research, Helmholtz-Zentrum Geesthacht, Germany

Received 22 February 2013; Accepted 2 May 2013

Academic Editor: Lian Xie

Copyright © 2013 Fei Chen and Hans von Storch. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The 6-hourly 1948–2010 NCEP 1 reanalyses have been dynamically downscaled for the region of the North Pacific. With a detecting-and-tracking algorithm, the climatology of North Pacific Polar Lows has been constructed. This derived climatology is consistent with the limited observational evidence in terms of frequency and spatial distribution. The climatology exhibits strong year-to-year variability but weak decadal variability and a small positive trend. A canonical correlation analysis describes the conditioning of the formation of Polar Lows by characteristic seasonal mean flow regimes, which favor, or limit, cold air outbreaks and upper air troughs.