Climate of the Past www.clim-past.net 1814-9324 1814-9332 4 3 2008 10.5194/cp-4-147-2008 http://www.clim-past.net/4/147/2008/ http://www.clim-past.net/4/147/2008/cp-4-147-2008.html http://www.clim-past.net/4/147/2008/cp-4-147-2008.pdf 147 152 2008-08-04 Shifts in early spring wind regime in North-East Europe (1955–2007) S. Keevallik T. Soomere soomere@cs.ioc.ee Marine Systems Institute at Tallinn University of Technology, Akadeemia tee 21, 12618, Estonia Centre for Nonlinear Studies, Institute of Cybernetics at Tallinn University of Technology, Akadeemia tee 21, 12618, Estonia Changes to the winter-to-spring switch-time of the upper air flow regime at the 850 and 500 hPa levels over the north-eastern Baltic Sea are analyzed based on a data set extending from 1955 to 2007. The long-term variation of the air flow in early spring (March) exhibits multiple regime shifts. 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