The effect of Ekman and geostrophic surface current on the distribution of SST variability over the Persian Gulf

The Impact of Geostrophic Transport on the Temporal and Spatial Structure of Wind-Driven Coastal Upwelling/Downwelling over the Persian Gulf

“…On the other hand, the probability of significant coastal upwelling in June had already been reported by [30,54], who inferred that the thermocline develops, particularly in the northern Persian Gulf in the summer, and increases the chances of upwelling. This is due to the influence of the prevailing Shamal winds in the area during June [25,34,46]. Additionally, the impact of monsoon waves generated during the monsoon season on the southern coastline of the Arabian Peninsula in the Indian Ocean, which approach from the south, may also contribute to the maximum value of the coastal upwelling index in June in this area [10].…”

“…According to Equation ( 9), the geostrophic transport has been obtained from the geostrophic component of the sea surface current, and the Ekman transport corresponds to the Ekman component of the sea surface current. According to Figures 1 and 2 in [34], the direction of the Ekman components is from northwest to south and southeast in June so that they flow parallel and in the same direction throughout the Persian Gulf, but the direction of the geostrophic components, which is one of the main factors in the formation of eddies in the Persian Gulf, is variable over the domain. This current component causes a counter-clockwise rotation in the Persian Gulf, so it flows from east to west on the northern coasts and from west to east on the southern coasts of the Persian Gulf.…”

“…The longitude and latitude are represented by x and y, respectively. The Coriolis parameter, f, has a value of 7 × 10 −5 s −1, the acceleration due to gravity, g, is 9.807 m s −2 and the height of the sea surface relative to the geoid is represented by h [34].…”

“…Previous studies have extensively explored various aspects related to the Persian Gulf, including mesoscale eddy activity [24][25][26][27][28], coastal upwelling [29][30][31], sea surface temperature distribution [32,33], and geostrophic and Ekman currents [34]. Furthermore, the impact of geostrophic transport on upwelling and especially downwelling has not been systematically investigated over the Persian Gulf.…”

“…According to a study by [34], the variability of various current types, including Ekman, geostrophic, and total currents, was analyzed using the northern Persian Gulf around 52.5 • E-53.5 • E daily time series data spanning 21 years (2000-2020). The study found that in the northern region of the Persian Gulf, the direction of the Ekman currents was toward the sea, leading to the formation of wind-driven coastal upwelling currents.…”