Tropical influence on Euro-Asian autumn rainfall variability

• Published in: Climate dynamics Vol. 24; no. 5; pp. 511 - 521
• Main Authors: MARIOTTI, A, BALLABRERA-POY, J, ZENG, N
• Format: Journal Article
• Language: English
• Published: Heidelberg Springer 01-04-2005; Berlin Springer Nature B.V
• Subjects: Autumn; Climate science; Climatology. Bioclimatology. Climate change; Earth, ocean, space; El Nino; Exact sciences and technology; External geophysics; Meteorology; Ocean currents; Rain; Rainfall; Southern Oscillation; Studies; Water in the atmosphere (humidity, clouds, evaporation, precipitation); AN, North Atlantic; I, Indo-Pacific; Indian Ocean; INW, Asia; Asia; Europe; MED, Africa, North; AS, Tropical Atlantic; ISW, Indian Ocean; Indo-Pacific Region; ANE, Europe; Teleconnection; rainfall; Autumn; atmospheric precipitation; Europe; Empirical orthogonal function; Climatic index; ocean-atmosphere interaction; Tropical climate; Rainfall rate; Interannual variation; Dynamical climatology; Seasonal anomaly; El Nino; Asia; Southern oscillation; Composite analysis
• ISSN: 0930-7575; 1432-0894
• DOI: 10.1007/s00382-004-0498-6

The connection between autumn 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 the El Niño Southern Oscillation (ENSO) and autumn rainfall in parts of southwest Europe, northern Africa and southwest Asia. The correlation between area-mean anomalies over this region (P^sub ea^) and the NIÑO3.4 index is 0.68, stationary over the last 50 years. Global ENSO-like tropical climate anomalies are observed in conjunction with P^sub ea^ anomalies confirming the relationship found with the NIÑO3.4 index. Overall, the connection with Indo-Pacific variability is stronger than that with the eastern Pacific.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. In the North Atlantic/European region, it is speculated that while a PNA-like mode maybe the prevailing teleconnection mechanism for high P^sub ea^, for low P^sub ea^ tropical Atlantic ENSO related SST anomalies may be playing a more relevant role forcing northeastward propagating Rossby waves. Over southwest Asia, a more direct connection to the Indo-Pacific region is suggested by the upper air anomaly observed over southern Asia, possibly the Rossby wave response to enhanced heating in the Indian Ocean.[PUBLICATION ABSTRACT]