Intraseasonal and Interannual Variability of the Indian Ocean

The behavior of the North Indian Ocean is examined using an intermediate ocean model modified for the use with real forcing fields. The model is run for 41 year using NCEP 5-days averaged data. Long term averages and annual cycles show good agreement with the observed current and SST data. The dynamics of the Indian Ocean heat balance are investigated on both interannual and intraseasonal time scales. The statistical analysis of the interannual variability is performed using principal component analysis. The climatology of the heat transport in the North Indian Ocean is calculated. The results demonstrate large interannual variability on different time scales and the Indian Ocean dipole variations. The role of wind-driven circulation and its interannual variability is analyzed in terms of its effect on meridional heat transport and heat storage. Meridional heat transport shows variation on 15 to 40 days scales. Investigated are possible reasons for such variations. The relative importance of the meridional circulation cell and eddies for the heat transport variability is discussed. We also discussed possible relationships of the heat transport variability in the monsoon region and the El Nino-Southern-Oscillation (ENSO).