Ocean-atmosphere coupling and the boreal winter MJO

Hye Mi Kim, Carlos D. Hoyos, Peter J. Webster, In Sik Kang

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38 Scopus citations


The influence of ocean-atmosphere coupling on the simulation and prediction of the boreal winter Madden-Julian Oscillation (MJO) is examined using the Seoul National University coupled general circulation model (CGCM) and atmospheric-only model (AGCM). The AGCM is forced with daily SSTs interpolated from pentad mean CGCM SSTs. Forecast skill is examined using serial extended simulations spanning 26 different winter seasons with 30-day forecasts commencing every 5 days providing a total of 598 30-day simulations. By comparing both sets of experiments, which share the same atmospheric components, the influence of coupled ocean-atmosphere processes on the simulation and prediction of MJO can be studied. The mean MJO intensity possesses more realistic amplitude in the CGCM than in AGCM. In general, the ocean-atmosphere coupling acts to improve the simulation of the spatio-temporal evolution of the eastward propagating MJO and the phase relationship between convection (OLR) and SST over the equatorial Indian Ocean and the western Pacific. Both the CGCM and observations exhibit a near-quadrature relationship between OLR and SST, with the former lagging by about two pentads. However, the AGCM shows a less realistic phase relationship. As the initial conditions are the same in both models, the additional forcing by SST anomalies in the CGCM extends the prediction skill beyond that of the AGCM. To test the applicability of the CGCM to real-time prediction, we compute the Real-time Multivariate MJO (RMM) index and compared it with the index computed from observations. RMM1 (RMM2) falls away rapidly to 0.5 after 17-18 (15-16) days in the AGCM and 18-19 (16-17) days in the CGCM. The prediction skill is phase dependent in both the CGCM and AGCM.

Original languageEnglish
Pages (from-to)771-784
Number of pages14
JournalClimate Dynamics
Issue number5
StatePublished - 2010

Bibliographical note

Funding Information:
This research has been supported in part by Climate Dynamics Division of the United States National Sciences Foundation under Award NSF-ATM 0531771 and NOAA CPPA project NA0600AR4310005. The fourth author has been supported by the Korea Meteorological Administration Research and Development Program under Grant CATER_2006-4206 and the second stage of the Brain Korea 21 Project. Much of the work presented here was accomplished during a visit by Hye-Mi Kim to the School of Earth and Atmospheric Sciences at the Georgia Institute of Technology in 2006.


  • MJO
  • Ocean-atmosphere coupling
  • Prediction


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