Simulation of SST fluctuations and circulation in the Equatorial Indian Ocean

Inter-annual variability in the equatorial Indian Ocean sometimes exhibits large Sea Surface Temperature (SST) fluctuations. The SST anomaly gradient between eastern and western equatorial Indian Ocean during summer season (June-October) becomes greater than 1(circle)C. This east-west SST anomaly gradient is independent of ENSO and may be a natural oscillation of the Indian Ocean. Such fluctuations are observed in many years during the decade 1990-2000. In the present study a 2(circle)layer thermodynamic ocean model has been used to simulate inter-annual variability in the circulation and SST anomaly (SSTA) fluctuations in the Indian Ocean. The model simulated SST over the Tropical Indian Ocean is in close agreement with observed SST. The warm SSTA in the western equatorial Indian Ocean and cold SSTA in the eastern equatorial Indian Ocean during the years 1994 and 1997 and, opposite SSTA during the years 1992 and 1996, are well simulated by the model.