Characteristics of subsurface mesoscale eddies in the northwestern tropical Pacifi c Ocean from an eddy-resolving model

作者：XU Anqi,YU Fei,NAN Feng,REN Qiang

摘要：Subsurface eddies(SSEs)are common features of the ocean interior.They are particularly abundant in oceanic basins and the vicinity of major intermediate water outfl ows.They are responsible for subsurface transport of mass,heat,and salt.Analysis of high-resolution general circulation model data has revealed the existence of subsurface anticyclonic eddies(SSAEs)and subsurface cyclonic eddies(SSCEs)in the northwestern tropical Pacifi c Ocean.SSEs are abundant east of the Philippines(0°–22°N,120°E–140°E)and in latitude bands between 9°N–17°N east of 140°E.The composite structure of SSEs was investigated.SSEs had a core at about 400-m water depth and their maximum meridional velocity exceeded 10 cm/s.They exhibited two cores with diff erent salinity polarities in the surface and subsurface.Additionally,spatial distributions of heat transport induced by SSEs in the northwestern tropical Pacifi c were presented for the fi rst time.A net equatorward heat fl ux toward a temperature up-gradient was observed.The analysis of eddy-mean fl ow interactions revealed that the circulation is baroclinically and barotropically unstable at diff erent depths and to diff ering degrees.The energy conversions suggest that both barotropic and baroclinic instabilities are responsible for SSE generation east of the Philippines,whereas baroclinic instability caused by a horizontal density gradient and vertical eddy heat fl ux are important between 9°N and 17°N east of 140°E.Meridional movement of the north equatorial current and the north equatorial undercurrent can contribute to SSE generation in our study region.

发文机构：Institute of Oceanology University of Chinese Academy of Sciences Key Laboratory of Ocean Circulation and Waves Center for Ocean Mega-Science Marine Dynamic Process and Climate Function Laboratory

关键词：thenorthwesterntropicalPacificOceansubsurfaceeddiescompositestructuresheattransportenergysource

分类号： P73[天文地球—海洋科学]