Wintertime Iberian peninsula precipitation variability and its relation to North Atlantic atmospheric circulation

To isolate the physical mechanism responsible for the relationship between North Atlantic large-scale circulation and precipitation amounts over Western Europe, a singular value decomposition (SVD) has been performed. This analysis is applied to a 30-winter dataset consisting of both monthly mean precipitation anomalies in Iberia and monthly mean 500 hPa geopotential height anomalies over the North Atlantic Ocean. The SVD analysis yields three significant pairs of patterns that account for 93% of the squared covariance between the two fields. This great amount of covariance indicates the strong coupling between large-scale circulation described by the 500 hPa height anomalies and the regional precipitation in the Iberian Peninsula.