Determination of the Current System on Isopycnal Surface Between Mindanao and New Guinea from GDEM

1 .INTRODUCTIONThewesternequatorialPacific ,particularlythesouthernmostPhilippineSea ,wascalled“watermasscrossroads”byFineetal.(1 994 )duetotheconfluencethereofseveralwatermassesfromhigherlatitudesofbothhemispheres (Wyrtki,1 96 1 ;Fineetal.,1 994 ) .Fineetal.(1 994 )de picted (Fig .1 )majorcurrentsintheIndonesianregion .AfterencounteringthewesternboundaryalongthePhilippinecoast,theNorthEquatorialCur rent (NEC)bifurcatesintothenorthwardflowingKuroshioandthesouthwardflowingMindanao…

Determination of the current system on isopycnal surface between Mindanao and New Guinea from GDEM

In this study, we used the Navy’s Generalized Digital Environmental Model (GDEM) climatological temperature and salinity data on a 0.5°×0.5° grid to investigate the seasonal variabilities of the southwest Philippines Sea (0.5°–9°N, 123.5°–136.5°) thermohaline structure and circulation. The GDEM for the area was built up on historical (1930–1997) temperature and salinity profiles. A three-dimensional estimate of the absolute geostrophic velocity field on isopycnal surface was obtained from the GDEM temperature and salinity fields using the P-vector method. The seasonal variabilities of the thermohaline structure and currents (obtained from the inverse method) such as the Mindanao Current, Mindanao Undercurrent, North Equatorial Counter Current, New Guinea Coastal Undercurrent, and dual-eddies (cyclinic Mindanao Eddy and anticyclonic Halmahera Eddy) are identified. Peter Chu and Fan Chenwu were supported by the Office of Naval Research and the Naval Oceanographic Office. Li Rongfeng was supported by NSFC (40076009), and Chinese Academy of Sciences (KZCX2-204, KZCX1-SW-01-16).