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South Pacific origin of the decadal ENSO‐like variation as simulated by a coupled GCM
Author(s) -
Luo JingJia,
Masson Sebastien,
Behera Swadhin,
Delecluse Pascale,
Gualdi Silvio,
Navarra Antonio,
Yamagata Toshio
Publication year - 2003
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 - 10.1029/2003gl018649
Subject(s) - climatology , thermocline , anticyclone , sea surface temperature , gcm transcription factors , geology , ekman transport , el niño southern oscillation , general circulation model , pacific decadal oscillation , walker circulation , environmental science , oceanography , climate change , upwelling
The hypothesis of the South Pacific origin of the decadal (7–35 years) ENSO‐like variation is investigated based on 200‐year outputs of the ECHAM4/OPA/OASIS coupled GCM. Associated with the decadal warm (cold) SST anomalies in the tropical Pacific, an anomalous cyclonic (anticyclonic) circulation, which is tilted in a southeast‐northwest direction, appears in the South Pacific. This results in anomalous upward (downward) Ekman pumping along the northeastern edge of the anomalous circulation and, hence, shallowing (deepening) the oceanic thermocline there. Such an external source of heat content tends to slowly discharge/recharge the tropical ocean on the decadal timescale. The above result is consistent with the observational study of Luo and Yamagata [2001]. Besides, the model reproduces amazingly a high lagged‐correlation between the global land surface temperature and the decadal Nino3 SST. Despite the model biases, this suggests a potential prediction skill of the global warming based on the ENSO‐like decadal variation.