Tidal Residual Circulations in the Arabian Gulf

Arabian Gulf (hereafter called as the Gulf) is a semi-enclosed marginal sea located along the northern boundary of Arabian Peninsula. The tides and its role in the circulation of the Gulf are still uncertain. Most of the previous modeling studies in the gulf neglected the role of tides on the net residual circulation. Thus, the tidal residual circulation has been studied using a high resolution 3-dimensional non-hydrostatic model based on MITgcm in the Gulf. A High precision bathymetry data is used and barotropic tidal currents of seven major tidal constituents M2, S2, N2, K2, K1, O1, and P1 are applied at the open boundaries. The MITgcm derived tidal elevations and currents are compared with 37 tide gauge stations and 5 mooring stations at different depths. The comparison shows good agreement with the observed tidal elevations, as well as, with the derived currents (tidal scale) with an average model skill value of 0.70. The MITgcm estimated tidal residual current shows a significant improvement compared with many previous modeling studies in capturing significant tidal features. These tidal features are: i) two amphidromic points caused by semi-diurnal tides in the southeast and southwest of the gulf, and one amphidromic point caused by diurnal components in the central southern Arabian Gulf; ii) strong tidal residual currents which reaches up to the order of 20 cm/sec along the periphery of deep channels; and iii) a series of strong cyclonic tidal residual eddies which may drive the net cyclonic residual flow in the gulf.