The influence of ENSO on winter North Atlantic climate

Abstract

Although the influence of the El Niño - Southern Oscillation on the extra-tropical climate is well established for the Pacific basin and North American regions, there is no clear consensus as to whether there are reproducible effects from ENSO on the North Atlantic and West European regions. In this study we present a revised analysis of past El-Niño teleconnections. By stratifying El-Niño events according to amplitude, we find a highly nonlinear yet robust response to ENSO that changes sign over the eastern North Atlantic as the amplitude of the El-Niño anomaly increases. Results from a series of experiments with a general circulation model indicate that the response to strong ENSO events is reproducible given the sea-surface temperature anomalies in the tropical Pacific. The response to moderate El-Niño events resembles the negative phase of the North Atlantic Oscillation as found in previous studies.