Measurement of tidal and residual currents in the Strait of Hormuz

Quantifying the current in the Strait of Hormuz (SH) is vital for understanding the circulation in the Persian Gulf. To measure the current in the strait, four subsurface moorings were deployed at four different stations close to SH from early November 2012 to the end of January 2013. Tidal current were dominant in the SH. The tides in the SH were complex partially standing waves and the dominant pattern varied from being primarily semi-diurnal to diurnal. The phase difference between tidal constituents of current and sea level elevation time series was used as an index to show the partially progressive wave pattern inside the study area. At mooring positions 3 and 4, located to the left of SH, the phase differences were close to 160° and 100°, respectively. It indicates partially progressive waves in opposite direction at these stations. K1 and M2 were the two main constituents at all stations inside the study area. At surface, the magnitude of semi-major axis of ellipses for M2 constituent was larger than corresponding value for K1 whereas at the bottom layer, the opposite pattern was observed. The M2 rotary coefficients at mooring 1 illustrated that current vector at the bottom layer rotated in opposite direction compared to current vectors at the middle and surface layers. The rotation was counterclockwise in the bottom layer, while it was clockwise in the surface and middle layers.