Tropical influence on Euro-Asian autumn rainfall

Annarita Mariotti



It has long been a matter of debate whether and how El Nino Southern Oscillation (ENSO) warm and cold extremes influence Euro-Asian rainfall. Since the early works on ENSO teleconnections, there has been increasing evidence supporting such a link and pointing to a strong seasonal dependence.

In this work, the connection between rainfall variability in the Euro-Asian domain and tropical climate is documented using state-of-the-art global observational datasets and re-analyses. Results suggest a robust statistical relationship between ENSO and autumn rainfall in parts of southwest Europe, northern Africa and southwest Asia, stationary over the last 50 years.

Global ENSO-like tropical climate anomalies are observed in conjunction with these rainfall anomalies confirming the relationship found with the NINO3.4 index. While rainfall anomalies in southwest Europe and southwest Asia appear to largely co-vary as one pattern under the influence of ENSO, our results suggest that different mechanisms may be contributing to the observed anomalies.