The purpose of this research is to understand the reasons for the existence of the deserts on the west coasts of major continents. The PI will carry out two modeling studies which are designed to investigate the roles of certain processes in the maintenance of the deserts. The first will explore the possibility that the longshore coastal low level flow represents an inertial boundary current blocked by the Andes. The second will look at the influence of the thermal gradient, caused by coastal upwelling, on the local circulation patterns. This research is importnat for improving our theoretical understanding of the general atmospheric circulation and climate regimes.