Abstract
Previous studies have shown that the Indian Ocean Dipole (IOD) has a
significant impact on land temperatures over southern Europe. However,
whether IOD influences rainfall over this region and how this impact
compares to that of El Nino Southern Oscillation (ENSO) have not been
established. Here using the E-OBS gridded rainfall datasets for the
period 1958 to 2012, we have analyzed the influence of IOD and ENSO on
European rainfall. We find that IOD impacts are predominantly felt over
southwestern Europe in a region covering Spain and Portugal during the
peak phase of the event. Correlations exceeding 0.4 are observed over
the central regions of Spain. We find that ENSO impacts on European
rainfall are substantially weaker compared to that of IOD, but occur
with a pattern similar to the latter. Partial correlation analysis
suggests that the marginal ENSO correlations are a statistical areifact
arising from the co-occurrence of a fraction of the El Nino events with
positive IOD events. Possible dynamical mechanisms by which IOD impacts
rainfall over southwestern Europe will be discussed.