Observations of tidal currents in the northern Gulf of Eilat/Aqaba (Red Sea)

The spatial and temporal variabilities of alongshore semi-diurnal tidal currents in the northern Gulf of Eilat/Aqaba are examined using long-term (10 month) observations of velocity measured by acoustic Doppler current profilers (ADCPs) deployed in deep, offshore waters and in the shallow coastal zone over the period October 2008 to July 2009. Semi-diurnal tidal currents were observed throughout the entire study in both the deep and shallow velocity records. This finding differs from previous studies that observed the disappearance of semi-diurnal tidal currents from January to May, suggesting that such a disappearance is not a predictable, recurring feature of tidal currents in the Gulf. The velocity records combined with monthly hydrographic data show that the persistence of the semi-diurnal tidal currents throughout the winter and spring likely resulted from shallow upper layer depths in 2009. The dependence of the magnitude of the semi-diurnal tidal currents on the seasonally varying stratification is examined.

► Tidal currents were observed in the northern Gulf of Eilat from summer 2008 to summer 2009.
► Current data were collected in shallow, near-shore and deep, offshore waters.
► We observed semidiurnal peaks in spectra of alongshore currents in all seasons.
► The variability of the alongshore semidiurnal tidal currents correlates well with the depth of the seasonal thermocline.