Links between circulation weather types and teleconnection patterns and their influence on precipitation patterns in Galicia (NW Spain)

Abstract

Abstract An automated version of the Lamb weather type classification scheme was used to study the relationship between atmospheric circulation patterns and rainfall in the northwestern part of the Iberian Peninsula, which is an important area of crossing influences of the different teleconnection patterns of the Northern Hemisphere. We calculated the correlation between the most important teleconnection patterns that affect this area and the different types of weather circulation. In this area, anticyclone weather types are the most frequent in any part of the year. The frequency of occurrence of W and SW situations is also significant in autumn and winter. The correlation between weather types (WT) and teleconnection patterns showed that the North Atlantic Oscillation (NAO) index has significant correlations only in winter, while other patterns, such as the Eastern Atlantic (EA), have significant correlations in the other seasons. As a result of these correlations, the EA is a more relevant pattern than the NAO for describing the Galician climate throughout the year. We also calculated correlations between the North Hemisphere Annular Mode (NAM) and the different types of weather types. The NAM shows significant correlations throughout the year. Hence, the NAM is more relevant than the NAO, which is its local manifestation. Copyright © 2007 Royal Meteorological Society