The westward intrusion of south Pacific water at the western tip of the New Guinea Island

Abstract

Fromthe eastern Indonesian cruise from November 14 to 23, 2007, CTD (conductivity, temperature, depth profiler) /ADCP (acoustic Doppler current profiler)casting and seawater sampling were done at 25 stations around Waigeo Island near New Guinea Island. It was found overall westward intrusion of the south Pacific waters into the Seram Sea and southward spreading of the north and south Pacific waters into the Seram Sea. There is westward residual flow along the channel between Waigeo and New Guinea within upper 200 m with the maximum speed up to 50 cm/s, and much weaker eastward flow in the lower layer (< 10 cm/s) due to blocking by the shallow sill at the west of the Dampier Strait. The abrupt change of bottom topography induces active horizontal and vertical mixing which results in a three-layered current system with a major through-flow of −0.99 Sv (Sv = 10⁶ m³/s) into the Seram Sea; the transports in the upper and the lower layers are −1.14 Sv and −0.24 Sv (westward), respectively, and in the middle there is a return flow with the transport of +0.39 Sv (eastward).