Investigation of Water Circulation and Temperature Effect in Indian Ocean by Perturbation Method

The tropical Indian Ocean forms the major part of the largest warm pool on Earth, and its interaction with the atmosphere plays an important role in shaping climate on both regional and global scales. Three dimensional temperature fields are calculated analytically for an ocean forced by wind stress and surface heat flux. A basic thermal state involving a balance of lateral and vertical heat diffusion is assumed. An effect of nonlinear heat advection is calculated by a perturbation method. The zero order temperature fields give a rough overall representation of oceanic thermocline. Associated with this field there is a baroclinic eastward flow in the upper part, with a westward return flow below. The interior temperature field to the next order is affected not only by interior heat advection but by heat advection in the Ekman layer, in the up and down welling layers and in the main western boundary current. For solving equations we use perturbation method. All equations are written in spherical coordinate and then compare with results in Cartesian coordinate.