| The upper circulation of the Indian Ocean is predominantly driven by the intense monsoon winds that reverse between summer and winter. At large scale, the winter time circulation pattern in the equatorial region of the Indian Ocean closely resembles the classic equatorial circulation, with a westward South Equatorial Current (SEC), an eastward South Equatorial Counter Current (SECC) and a westward North Equatorial Current (NEC). The southward Somali Current and northward East African Coastal Current meets at 2 - 4 degree South, and supplies the eastward SECC. In summer, the NEC disappears, and the SECC moves northward and combines with the Southwest Monsoon Current, contributing to the eastward flow over most of the north Indian Ocean. These current systems are also rich in mesoscale eddies and meanders. During a typical summer monsoon, the northward Somali Current turns offshore at about 4 degree North, and the ″Southern Gyre″, the ″Great Whirl″ and the ″Socotra Eddy″ are often present in the Somali Current region. Additionally, current system associated with the Indonesian Throughflow also carries mesoscale meanders as it moves westward. Thus, eddy resolving models are needed to properly simulate the large- and meso-scale features in the Indian Ocean current system. In this study, we used a suite of models with nearly identical physics and numerics that only differ in horizontal resolution to simulate the Indian Ocean circulation. The resolutions used in the simulations include 2, 0.7, 0.18 degree, and a varying resolution grid system (0.25 - 1 degree). The similarity and the differences among these simulations will be presented. |
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