Surface wind and upper ocean variability associated with the Madden-JulianOscillation (MJO) is examined using a regional coupled model: the Coupled Ocean/Atmosphere Prediction System (COAMPS). COAMPS is configured for the tropical Indian Ocean domain (40E-145E, 30S-30N) with the horizontal resolution of 27 km for the atmospheric component and 1/8° for the ocean component. The higher resolution of nested grid (9 km) for the atmospheric component is used for the central Indian Ocean near the equator (66E-85E, 10S-5N). Observational data are assimilated into the atmospheric component (12 hour cycle), but no data are assimilated into the ocean component. The ocean component uses the exceptionally fine vertical grid interval to resolve intraseasonal and diurnal variability of the upper ocean.

The model was integrated for the period April 1-30, 2009 when an active episode of large scale convection associated with the MJO passed eastward across the tropical Indian Ocean. Surface winds and upper ocean temperature and currents near the equator are compared with in-situ and satellite observations. It is demonstrated that westerly wind events associated the MJO are well reproduced by the model. Also, the model is able to well simulate the evolution of mixed layer and SST and the generation of equatorial jet in response to the westerly wind events.