Seasonal Variations of the Ocean Surface Circulation in the Vicinity of Palau
NAVAL RESEARCH LAB STENNIS SPACE CENTER MS OCEANOGRAPHY DIV
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The surface circulation in the western equatorial Pacific Ocean is investigated with the aim of describing intra-annual variations near Palau. In situ data and model output from the ocean surface currents analysis--real-time, triangle trans-ocean buoy network, Naval Research Laboratory layered ocean model and the joint archive for shipboard ADCP arc examined and compared. Known major currents and eddies of the western equatorial Pacific are observed and discussed, and previously undocumented features are identified and named Palau Eddy, Caroline Eddy, Micronesian Eddy. The circulation at Palau follows a seasonal variation aligned with that of the Asian monsoon December-April July-October and is driven by the major circulation features. From December to April, currents around Palau are generally directed northward with speeds of approximately 20 cms, influenced by the North Equatorial Counter-Current and the Mindanao Eddy. The current direction turns slightly clockwise through this boreal winter period, due to the northern migration of the Mindanao Eddy. During April-May, the current west of Palau is reduced to 15 cms as the Mindanao Eddy weakens. East of Palau, a cyclonic eddy Palau Eddy forms producing southward slow of around 25 cms. The flow during the period July to September is disordered with no influence from major circulation features. The current is generally northward west of Palau and southward to the east, each with speeds on the order of 5 cms.
- Physical and Dynamic Oceanography