The general circulation of the Gulf of Aqaba (Gulf of Eilat) revisited: The interplay between the exchange flow through the Straits of Tiran and surface fluxes

The Gulf of Aqaba (Gulf of Eilat) is a terminal elongated basin that exchanges water with the northern Red Sea via the Straits of Tiran. The gulf's hydrography exhibits strong seasonal variability, with deep mixing during February–March and stable stratification afterward. We use an oceanic model to investigate the annual cycle of the general circulation and hydrographic conditions in the gulf. We demonstrate that on a subannual time scale, the general circulation deviates from the standard depiction of inverse estuarine circulation. During the restratification season (April–August), the exchange flux with the northern Red Sea is maximal and is driven by density differences between the basins, while atmospheric fluxes actually counteract this exchange flow. The observed warming of the surface layer is mainly due to advection of warm water from the northern Red Sea, with a smaller contribution from surface heating. During the mixing season (September–March), the exchange flux and the advection of heat are minimal and atmospheric fluxes drive convection rather than the exchange flow. We estimate the seasonality of the exchange flow through the Straits of Tiran. The seasonal variability in the exchange flow is large and ranges from 0.04 Sv during early spring to 0.005 Sv during early winter. Key Points We demonstrate that the common view of inverse estuarine circulation is incorrect We simulate for the first time the annual cycle of exchange flow with the Red Sea We simulate and explain the evolution of subsurface salinity minimum