P4.8
El Nino teleconnections in an atmospheric model
Sarah Ineson, Met Office Hadley Centre, Met Office, Exeter, United Kingdom; and A. A. Scaife
Filling of the stratospheric polar cyclone and weakening of the polar night jet occurs during El Nino and is likely due to increased Rossby wave driving. Recent studies have also shown a weakened stratospheric jet is associated with more easterly tropospheric winds and colder European surface conditions resembling the negative phase of the North Atlantic Oscillation in the majority of El Nino events. Here we show results from a vertically extended (60-level) version of the HadGAM model with observed sea surface temperatures from 1960-2000. A composite of El Nino events shows both an infilling of the polar vortex and a negative January-February NAO signal, indicating a potential source of seasonal and intra-seasonal predictability for Europe in winter at long lead times.
Poster Session 4, Climate of the 20th Century (C20C) Poster Session
Wednesday, 23 January 2008, 2:30 PM-4:00 PM, Exhibit Hall B
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