Wintertime variability of Mediterranean precipitation and its links with large-scale circulation anomalies

摘要: A standard principal component analysis has been performed over the Mediterranean and larger European region on monthly precipitation anomalies for winters between 1979 1995. The main centres of action associated EOFs are very similar two regions sets PCs highly correlated with each other. Focusing region, same using 500 hPa geopotential height taken from operational NCEP analysis. Comparing upper-air surface data, a strong correlation found suggesting presence two-way link regional patterns large-scale circulation anomalies. For both fields, largest fraction variance is explained by North Atlantic Oscillation, while smaller but still substantial fractions other known variability such as Eastern pattern Euro-Atlantic blocking. No detectable connection El Nino SST during winter. With respect to temporal variability, significant trends have most areas considered. characterised increase western Scandinavia general decrease southern Europe. This result confirmed analysing data stations located in northern Italy.