Subthermocline Eddies in the Western Equatorial Pacific as Shown by an Eddy-Resolving OGCM*

Abstract

Abstract Sporadic in situ observations have shown evidence that subthermocline eddies exist off the Mindanao coast. These subthermocline eddies are believed to play an important role in the heat, freshwater, and other ocean property transports of the region, but their characteristics and in particular their pathway and source of energy are poorly explored because of the lack of long-term observations. Analysis of results from an eddy-resolving general ocean circulation model has revealed that most subthermocline eddies off the Mindanao coast originate from the equatorial South Pacific Ocean to the west of the Ninigo Group. These eddies propagate northward along the New Guinea coast, cross the equator in the far western Pacific, and reach the Mindanao coast at a typical propagation speed of ~0.12 m s−1. The dominant time scales of these eddies range between 50 and 60 days.