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Nonstationary impact of ENSO on Euro‐Atlantic winter climate
Author(s) -
Greatbatch Richard J.,
Lu Jian,
Peterson K. Andrew
Publication year - 2004
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2003gl018542
Subject(s) - climatology , extratropical cyclone , teleconnection , tropics , forcing (mathematics) , el niño southern oscillation , environmental science , southern oscillation , tropical atlantic , climate change , atmospheric sciences , geology , oceanography , sea surface temperature , fishery , biology
Previous studies have suggested a lack of robustness over the Euro‐Atlantic sector in the extratropical teleconnection response to ENSO. We use a simple AGCM to show that during the 20 years before and after the late 1970's, the ENSO signal leaving the tropics has the character of a wave train that is similar to the PNA, but is much stronger and penetrates further poleward in the post 1970s period. We also find that the synchronous extratropically‐forced model response is almost the reverse in the post‐ compared to the pre‐late 1970s period. We argue that the change in the signal leaving the tropics is due to the sensitivity of the tropically‐forced signal to changes in the spatial pattern of the tropical forcing. The extent to which the extratropically‐forced response is itself dependent on the tropical forcing, or simply the result of chance, is not clear.