Seasonal variations of eddies in North Indian Ocean using wind data and satellite altimetry

Identifying surface current fluctuations on a monthly basis in an oceanic area, it is possible to recognize the manner of pollutant accumulations, sea fronts, and ocean eddies’ propagations. Investigation of eddies as important factors in horizontal ocean mixing is also essential because of their influence on biological population in the sea, the transfer and distribution of heat and salinity, and the ocean heat exchange with the atmosphere. Observations show that the sea surface current is usually controlled by two factors including: Ekman component (wind driven) and geostrophic parameter (due to the changes in mean sea level). Because direct field measurements for ocean currents are difficult and time consuming, the monthly OSCAR satellite data for the Indian Ocean are used for a period of three years, to map current vectors that are illustrated in the ArcMap software. Indexed eddies for each season are identified and their characteristics are investigated. The results show that the eddies formed in summer and autumn have the higher speeds with maximum value of about 1.3 m/s of the Somali Coast and less energetic ones are formed over the other vast oceanic areas. While the ones created in winter have maximum velocity of about 1.5 m/s and also the currents with intermediate-scale have a velocity of 0.7 m/s.