Winter 10-Day Coupled Patterns between Geopotential Height and Iberian Peninsula Rainfall Using the ECMWF Precipitation Reanalysis

Abstract

Ten-day winter anomalous precipitation variability in the Iberian Peninsula (IP), related to the North Atlantic atmospheric general circulation, is analyzed using 24-h forecast ECMWF precipitation data over 1979?96. The three main modes that explain the 10-day winter precipitation variability are described using the empirical orthogonal function (EOF) analysis. Singular value decomposition (SVD) analysis between the anomalous geopotential height for different levels and the IP precipitation is used as a tool to establish the relation between the precipitation and the North Atlantic atmospheric general circulation, showing how the first three SVD modes collect practically all possible precipitation?atmosphere links in these timescales. These resultant SVD atmospheric patterns are related to other known teleconnection patterns, such as the Arctic Oscillation (AO), the North Atlantic Oscillation (NAO), the Scandinavian pattern (SCA), and the east Atlantic pattern (EA). At the same time, the main results are compared with those obtained from station precipitation data. The good agreement with the significant coupled patterns obtained when using observed precipitation data is shown as a further way of validating the precipitation 24-h forecast of the ECMWF dataset for these types of studies.