The Kuroshio Structure and Transport Estimated by the Inverse Method

Abstract

Abstract Structure and transport of the Kuroshio are examined by the inverse method, based on a dataset around the Tokara Strait. Subsurface velocities measured by a shipborne acoustic Doppler current profiler are used together with CTD sections across the Kuroshio to estimate the absolute flow fields. The dataset was obtained along a closed line south off the Kyushu by the R/V Chofu Maru in September 1987. The Kuroshio transport through the Tokara Strait was 28 × 109 kg s−1 at the time of observations. The transport of warm water eddy south of the Kuroshio is estimated at larger than 39 × 109 kg s−1, but its precise value is difficult to determine because of strong transport dependency on the solution rank. The result also suggests a southward flow below the Kuroshio off Cape Toimisaki and in the Tokara Strait. In the section east of Amamioshima Island, a broad northward flow is suggested on the continental slope.