Dynamics of the Persian Gulf Outflow

Situated north of the Arabian Sea, the Persian Gulf is subject to strong evaporation whichdominates precipitation. Warm and salty waters are thus produced in this marginal sea andfeed an outflow at depth in the Arabian Sea. Although its signature in terms of water massproperties is observed far offshore the Strait of Hormuz, mechanisms that govern its dynamicsremain poorly studied. High resolution (2 km) regional and idealized numerical models areused to investigate the dynamics and spreading pathways of the Persian Gulf outflow. ThePersian Gulf Water (PGW) undergoes a stage of hydrostatic adjustment that sets its deptharound 200 m. Its fate is then found to be strongly driven by highly energetic seasonal surface-intensifed mesoscale eddies that stir the characteristic properties of the PGW. Interactionswith boundaries, noticeably capes, also lead to detachment of short-lived intense submesoscalecoherent vortices that are advected along the edges of the mesoscale eddies. Strain and sheargenerated by these eddies are in fact comparable to the relative vorticity, thus compete with it.