On the connection between winter anomalous precipitation in the Iberian Peninsula and North West Africa and the summer subtropical Atlantic sea surface temperature

Abstract

Recent studies show that the state of the winter NAO is led by changes in the North Atlantic (NA) sea surface temperature(SST) with some months in advance. This finding encouraged us to analyze the possible predictability of the precipitation in the Iberian Peninsula and North West Africa (IPNA) regions, two of the most NAO affected areas. The results of a lag-Singular Value Decomposition analysis with the precipitation and the SST anomalies, show a possible connection between the first mode of the anomalous IPNA winter precipitation and the previous summer SST anomalies over the North Atlantic (NA) basin. The use of a Monte Carlo test confirms the significance of the results. And moreover, this SST pattern tends to persist from the previous summer months in the subtropical NA. To show that this connection is robust, a crossvalidation analysis is performed using, as a predictor, the anomalous summer SST in the NA basin.