An Investigation of the Hydrography of Chabahar Bay Using FVCOM Model and EOF Analysis

Abstract Chabahar Bay is a semi-enclosed and shallow omega-shaped bay, located on the south-eastern coasts of Iran. The 3D unstructured-grid Finite-Volume Coastal Ocean Model was employed to study the physical characteristics of water in Chabahar Bay. The correlation coefficients between the model and available measurements were 0.99 and 0.84 for water level and current velocity, respectively. The numerical results show that the depth averaged temperature of the Bay generally decreases from north to south and varies between 20-26 °C during the year. The basin average of annual salinity is 36.1 psu. Hence, the density increases from north to south and is strongly affected by temperature changes. The vertically average of sigma-t varies between 21.5-24.0 kg/m3. In the northern half of the Bay a warm center eddy is formed from March; during July, it strengthened and peaked in August. With Applying EOFs analysis on model surface temperature four principal patterns were determined. EOF1 corresponds to the bathymetry of the region and shows the heat capacity of the Bay, it is in accordance with the monsoon conditions. EOF2, 3, and 4 are corresponding to the effect of the wind. Due to dominant winds a strong upwelling was determined along the western coast.