Shifts in early spring wind regime in North-East Europe (1955?2007)

S. Keevallik (1) , T. Soomere (2)

1 MSI - Marine Systems Institute
2 Institute of Cybernetics [Tallinn]

Changes of the winter-to-spring switch-time of the upper air flow regime at 850 and 500 hPa levels over the north-eastern Baltic Sea are analyzed based on a data set extending until 2007. The long-term variation of the air flow in early spring (March) exhibits multiple regime shifts. The shifts are extracted by means of a vector analysis of the monthly mean air flow as well as the statistical shift detection technology. In the middle of the 1960s the average air flow turned from NW (WNW) to W (WSW) at the 500 (850) hPa level. The original regime was restored in the mid-1990s. The regime shifts in the average air flow in March can be interpreted as changes in the transition time from winter to summer circulation type.

Domaines: Interfaces continentales, environnement; Sciences de la Terre

S. Keevallik, T. Soomere. Shifts in early spring wind regime in North-East Europe (1955?2007). Climate of the Past Discussions, 2008, 4 (2), pp.271-287. ⟨hal-00298211⟩