A Numerical Study of the Frontal System between the Inflow and Outflow Waters in the Persian Gulf

Abstract

In this study the dynamical characteristics of the salinity front between the Persian Gulf inflow and outflow were studied using the HYCOM numerical model. This model was integrated for 5 years from the beginning of 2011 to the end of 2015and the results of 2015 were discussed. The results of the model clearly showed seasonal variations in the salinity front in which the intrusion of the salinity front extends much farther into the Persian Gulf in summer. The salinity front appears to be prone to baroclinic instability with maximum intensity in spring and summer months (with a strong density stratification), forming cyclonic eddies (saline center) and anticyclones (sweeter center), that peaks in August. Results showed that some anti-cascade processes occur in mesoscale eddy activity, in agreement with the quasi-two-dimensional turbulence behavior. Spectral analysis of salinity time series in the front showed eddies with time scales ranging from a few hours to about 3 months. The result also showed that there was a reasonable relation between mixed layer depth and the formation of mesoscale eddies, so that mesoscale eddies disappeared when the thickness of mixed layer was increased in winter.

Keywords

• Frontal system; Baroclinic instability; Mesoscale eddy; HYCOM; Persian Gulf.