Multi-core structure of the main part of the Kuroshio at G-PN section in the East China Sea

Sectional velocity distribution of the East China Sea Kuroshio is one of the basic points in the study of the Kuroshio. Hydrographic temperature and salinity data at G-PN section in the East China Sea from June 1955 to November 2001 are collected and properly processed to calculate the geostrophic current using dynamic height method at the transect of the Kuroshio. After analysis of calculation results, the basic current structure of the Kuroshio in its main part is examined together with scalar estimate and characters of multicore structure, and spacial-temporal variations of current cores＇ position. Main result shows that （1） single-core structure, double-core structure and multi-core structure are basic forms in axial part of the Kuroshio; （2） abvious temporal variations exist in current structure of the Kuroshio; （3） the current of structure of the Kuroshio has distinctly seasonal association. The number of current cores is on the high side of core numbers in average and multi-core stucture appears in fall mostly.