Large-scale Hydrography and Circulation of the Red Sea

A Collaboration between King Abdullah University of Science and Technology (KAUST) and the Woods Hole Oceanographic Institution (WHOI), Amy Bower PI

The Red Sea, which connects the Mediterranean Sea with the Indian Ocean, is an ocean basin of local, regional and global significance for human activities. It is fringed by extensive coral reefs, many in pristine condition, that provide critical habitat for marine life, support several important fisheries and attract tourists. One of the World’s most important shipping route between North America, Europe and Asia passes through the Red Sea, and it includes the largest commercial shipping port in the Middle East, Jeddah City.

In spite of its economic and environmental importance, our knowledge of the oceanographic conditions in the Red Sea, and the physical processes that drive it, are at this point rudimentary.  We know that the Red Sea is relatively unique in that large amounts of fresh water are transferred from the ocean to the overlying atmosphere (about 2 meters per year) through evaporation. This leads to the formation of a hyper-saline, dense water mass, Red Sea Water (RSW) that escapes from the Red Sea into the Indian Ocean as a dense overflow through Bab al Mandeb. But the details of the circulation within the Red Sea itself and its variability on time scales from diurnal to interannual are largely unknown, due mainly to the paucity of oceanographic and meteorological observations.

A few oceanographic numerical models have used basic information on large-scale winds, evaporation and heating to predict the circulation of the Red Sea, but the available data are insufficient to verify the model results. Furthermore, such models have not previously been designed to resolve the circulation along the coast of Saudi Arabia. We expect that regional wind and evaporation patterns, surface gravity waves, “internal” waves, instabilities of large-scale currents, rectification of tidal currents, bathymetric steering and other processes are important in setting the local circulation in the coastal region.

To significantly improve our understanding of the hydrogrpahy and circulation of the Red Sea, and to provide the first comprehensive undersanding of the physical oceanography of the Red Sea, we are conducting repeated  large-scale hydrographic and current surveys to document seasonal and interannual variability in water mass properties and currents throughout most of the Red Sea coastal waters off Saudi Arabia. These exploratory surveys would represent the first systematic mapping of the physical characteristics of the Saudi coastal waters and will be used to determine seasonal variability and the most appropriate sites for a coastal observing network.