An analytical model for a coastal boundary current was used to investigate heat and salt budget of exchange
flows in the Persian Gulf as a marginal sea. Coastal boundary currents exchange heat and freshwater with the mosphere and the offshore waters. As heat and salinity fluxes caused by air-sea interaction and eddy activities, different temperature and salinity associated with boundary currents are adjusted on different length scales. Results
obtained from the model show that the temperature and salinity length scales of coastal boundary current are 455 km and 914 km, for summer respectively for summer. In summer the inflow current density initially decreases to a local minimum and then increases, and finally flowing out the basin area with higher density than that of for the inflow. In winter, the estimated temperature and salinity length scales of coastal boundary current are 60 km and 64 km, respectively. In this season, density increases at the beginning with a steep slope and reaches a constant value and, finally the current flows out of the basin area.