Seasonal Behaviour of Mesoscale Eddy Trajectories in the North Indian Ocean Based on Satellite Altimetry

In the north Indian Ocean (NIO), maps of sea level anomaly from satellite altimetry were analysed January-1995 to December-2000. The study attempted trace trajectories individual mesoscale anomalies manually and understand seasonal changes in terms phase speed. Mesoscale are detected as concentric circular shapes diameters ~90 km 600 minimum 30 days life cycle. Relatively higher eddy kinetic energy was noticed northwestern region NIO. Individual anomalies, namely positive (warm, anticyclonic eddies) negative (cold, cyclonic showing travelling direction westward NIO basins. autumn, number is more than vice versa during summer. propagating (negative) Arabian Sea start appearing winter (spring) along (away from) west coast India 65°E; move spring/summer/autumn collide Somalia’s & coast. A group appears a tail at southern tip located Laccadive ridge (summer autumn) associated with LH (LL). Bay Bengal (BB) show southwestward northern BB, central BB northwestward BB; Andaman Nicobar ridge. zonal speed decreases away equator, magnitude varies longitudinally each season form wave-like pattern autumn summer; cycle wave almost 365 (a year). theoretical first mode baroclinic Rossby waves quite similar that averaged Therefore (eddies) embedded into large like phenomenon (Rossby waves), responsible for creating high variability EKE western boundaries.