Arabian Sea is a region of active air-sea interaction processes and plays a major role on driving monsoon system over the Indian subcontinent. Two important issues about the Arabian Sea have to be noted. (1) The annual evolution of the near-surface layer thermal structure undergoes a unique semiannual cycle and (2) the central Arabian Sea is a region of net heat gain across the air-sea interface over a year. It is thus of interest to determine how the heat is transported and ultimately removed from the region. To address this problem, a model based diagnostic study of the upper ocean thermal structure has been carried out in the central Arabian Sea using various in situ and optimal interpolated satellite data sets to quantify the role of various intervening processes at work. Several sensitivity experiments are also carried out to assess the role of salinity and uncertainty in air-sea fluxes and advective heat flux estimates in simulating the thermal structure.