HYDROGRAPHIC INDICATIONS OF ADVECTION CONVECTION EFFECTS IN THE GULF OF ELAT

The convective/advective balance at the northern end of the Gulf of Elat was investigated by comparing observed data to a numerical model's predictions. The data, monthly temperature and salinity profiles collected from July 1988 to August 1989, indicate a continuously developing annual cycle. with the water column reaching vertical homogeneity in February and the new thermocline beginning to develop in March. In the summer, an upper 200 m thermally stratified layer (surface temperatures reaching 26-degrees-C) overlies a thermally homogeneous layer of 21-degrees-C. Salinity is close to 40.5 parts per thousand and varies by less than 0.5 parts per thousand throughout the year, although a salinity minimum develops in the upper layer in late spring and erodes and deepens in the fall and winter as the water column becomes mixed. The strictly one-dimensional convective model successfully reproduces the thermal structure, with a slight lag in summer thermocline development, but is unable to predict the observed salinity minimum. The addition of some advected Red Sea water (40.3 parts per thousand) to the model enables the reproduction of the salinity minimum. This inflow of warmer water also may account for the relatively early thermocline development.