Japan Geoscience Union Meeting 2014

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Symbol A (Atmospheric, Ocean, and Environmental Sciences) » A-CG Complex & General

[A-CG37_28PM2] Multi-scale ocean-atmosphere interaction in the tropics

Mon. Apr 28, 2014 4:15 PM - 5:59 PM 423 (4F)

Convener:*Motoki Nagura(Japan Agency for Marine-Earth Science and Technology), Takuya Hasegawa(Japan Agency for Marine-Earth Science and Technology), Ayako Seiki(Japan Agency for Marine-Earth Science and Technology), Tomoki Tozuka(Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo), Hiroki Tokinaga(International Pacific Research Center, University of Hawaii), Masamichi Ohba(Central Research Institute of Electric Power Industry (CRIEPI), Environmental Science Research Laboratory), Yukiko Imada(Atmosphere and Ocean Research Institute, the University of Tokyo), Chair:Tomoki Tozuka(Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo), Masamichi Ohba(Central Research Institute of Electric Power Industry (CRIEPI), Environmental Science Research Laboratory)

4:35 PM - 4:50 PM

[ACG37-14] The role of interaction between the Pacific and the north Atlantic Oceans in the prediction of ENSO

Kuniko YAMAZAKI1, Yukiko IMADA1, Masahiro WATANABE1 (1.Atmosphere and Ocean Research Institute, the University of Tokyo)

Keywords:ENSO, the north tropical Atlantic climate variability, seasonal prediction, atmosphere and ocean general circulation model

Observational and climate modelling studies indicate a close link between the north tropical Atlantic (NTA) sea surface temperature anomalies (SSTA) and the El Nino-Southern Oscillation (ENSO). An El Nino peak in boreal winter is followed by a warming of the NTA SSTA in the subsequent spring, which in turn leads to a La Nina in the following autumn/winter. Using the seasonal prediction system based on the atmosphere and ocean general circulation model (AOGCM) MIROC5, we conducted an ensemble of hindcast experiments from 1979 to present, in which the transition from El Nino to La Nina in 1997-1998 was successfully predicted. We also conducted a series of accompanying sensitivity experiments targeted at the transition event in 1997-1998, in which the NTA or equatorial Pacific air-sea interactions were decoupled. We found that NTA SSTA plays an important role in increasing the skill in predicting the following La Nina event. We also found that the preceding particularly-large El Nino SSTA and the associated atmospheric bridge are essential for the generation of NTA SSTA of the observed magnitude.ReferencesHam, Y.-G., J.-S. Kug, J.-Y. Park, and F.-F. Jin, 2013: Sea surface temperature in the north tropical Atlantic as a trigger for El Nino/Sourthern Oscillation events, Nature Geoscience, 6, 112-116.