A Mathematical Model for Indian Ocean Circulation in Spherical Coordinate

In recent years, the Indian Ocean (IO) has been discovered to have a much larger impact on climate variability than previously thought. This paper reviews processes in which the IO is, or appears to be, actively involved. We begin the mathematical model with a pattern for summer monsoon winds. Three dimensional temperature and velocity fields are calculated analytically for the ocean forced by wind stress and surface heat flux. A basic thermal state involving a balance of lateral and vertical heat diffusion is assumed. The wind stress is chosen such that a tropical mass transport gyre is generated. An effect of nonlinear heat advection is calculated by a perturbation method. The zero order temperature field gives a rough overall representation of oceanic thermocline. A baroclinic eastward flow in the upper part, with a westward return flow below is associated with this field.This circulation is closed through thin up and downwelling layers at the sides. Superimposed, there is a barotropic wind driven circulation, with a transport field of the type described by Munk. The interior temperature field to the next order is affected, not only by interior heat advection but also by heat advection in the Ekman layer, in the up and downwelling layers and in the main western boundary current.