Orographically controlled cross-equatorial flow

Synoptic analyses, results from models, and theoretical studies of the low level jet stream of the Indian Ocean are presented. In both winter and summer, the strongest cross-equatorial flow is in the west at about 40 deg E regardless of the direction of the flow, probably because of the barrier of the mountains of East Africa. Transient features, diurnal variations, and individual jet streams are associated with the flow. It appears that the flow is driven by the Mascarene high monsoon trough system. It is shown that a divergence, simulates many of the characteristics of the low level jet.