Analysis and regionalization of northern European winter precipitation based on its relationship with the North Atlantic oscillation

Abstract

AbstractThe relationship between the North Atlantic oscillation (NAO) and winter temperature and precipitation over northern Europe has long been known. However, its strength is variable within this region. In this paper, an analysis of the regional variability of the influence of the NAO on winter precipitation in northern Europe is developed using empirical orthogonal function analysis, cluster analysis and simple correlation. Results show that precipitation in most of the region studied is affected by the NAO, although with varying intensity. The NAO strongly influences winter precipitation along the Norwegian coast, in northern Sweden and in southern Finland. It is evident that the region on the lee side of the Scandes (the mountain chain between Norway and Sweden) is protected from the effects of the moist western winds from the Atlantic that, in turn, are strongly related to the NAO. As a result, precipitation in this shielded area is mainly related to southeasterly winds. Copyright © 2003 Royal Meteorological Society