Analysis of sea surface height variabilities in the Kuroshio Current region by using Geosat altimeter data

The Geosat altimeter ERM T2-GDRs data were used to analyze sea surface height (SSH) variabilities in the Northwest Pacific region of 10°-45°N, 120°-160°E covering all the Kuroshio Current.After processing the Geoset GDRs data, the 50 gridded SSH anomaly fields were acquired.The comparison between the SSH anomalies and tidal gauge sea levels showed that the altimeter data accorded with the tidal gauge data especially in the low frequency scale and in open sea.The mesoscale variability energy distribution obtained from the SSH anomalies was controlled by the position of the Kuroshio, bottom topography and the stationary meander of the Kuroshio.The relative transports of the Kutoshio Extension and the Kuroshio south of Japan, represented by the difference between the SSH anomalies on two sides of the current, had strong interennual and seasonal cycles, which was related to the Kuroshio large meander.When the Kuroshio meander occurred, the transport of the Kuroshio east of the Tokara Strait decreased, but that northeast of Taiwan Island increased.The variability of the transport east of the Philippines reflected the effects of the ENSO.The EOF analysis of the SSH anomaly fields showed that the first three EOFs accounted for 25.3%,17.1% and 13.7% of the total variance, and represented the meander mode, the ENSO mode and season mode respectively.