Circulation in the Gulf of Aqaba (Red Sea) during winter—spring

Abstract

This study is devoted to oceanographic features of the semi-enclosed Gulf of Aqaba, Red Sea. The data were recorded in winter-spring 1999 on the R/V Meteor cruise leg 44/2. Temperature and salinity profiles were measured at six positions (I-VI). The shipboard NarrowBand Acoustic Doppler Current Profiler (NB ADCP) 150 kHz con- tinuously recorded current profiles down to 350 m en route. The research revealed that the current near the Strait of Tiran front (position VI) represents a semidiurnal signal of an internal tide wave (~12 h period; 0.2 ms -1 amplitude) that might be gen- erated by the barotropic tide at the sill of the Strait. A sequence of cyclonic and anti- cyclonic eddy pairs is found along the axis of the Gulf of Aqaba during winter-spring seasons. These sub-mesoscale signals are dominant above the main thermocline and might be caused by wind forcing and the narrowness of the Gulf; it might remain in other seasons with different dimensions in relation to the depth of thermocline. The total diameter of each pair was twice the baroclinic Rossby radius ( R ≈ 10 km). A single anti-cyclonic eddy was observed in the upper 300 m in the northern tip of the Gulf with a diameter of about 5-8 km.