Baroclinic transport of the Kuroshio Extension between 141°E and 165°E

Abstract

Using a water-mass-based climatology of temperature and salinity, geostrophic transports derived from dynamic height differences across the width of the Kuroshio Extension are presented. The dynamic height differences are obtained by calculating dynamic heights in the warmer water mass south of the Kuroshio and the cooler water mass north of the Kuroshio. The mean baroclinic transport is examined between 141øE and 165øE relative to several pressure levels. The baroclinic transports are sensitive to the selection of the northern and southern boundaries. The baroclinic transports increase from 141øE to about 145øE and decline east of 145øE. The computed seasonal variation of the longitudinally averaged baroclinic transport shows a minimum during spring and a broad maximum from July to November.

Study of transport variations in the Kuroshio extension system at 35° N, 147° E based on the data of Argo floats and satellite altimetry

“…According to these data, the Kuroshio Extension transport across the 152° E section is 87 ± 21 Sv [9]. The calculations of the Kuro shio Extension transport across 147° E using the dynamic method in [10] depend on the selection of the reference level: 86 Sv for the reference level at 2000 dbar and 77 Sv for the reference level at 1000 dbar, which also agrees well with the obtained results.…”

Modulation of the seasonal signal of the Kuroshio Extension during 1994 from satellite data

“…Clearly, the seasonal signal in kinetic energy undergoes interannual variations for this time period. The year 1993 has the seasonal character described by Clifford and Horton [1992] with highest energy values during fall and decreasing during winter. In 1994 the marked increase during fall does not occur, and in fact, the peak values are less than those for the previous winter; the drop is not nearly as Also, the Oyashio appears to be more northward than in August 1993, and there is a clear indication of strong advection by the Kuroshio up to 38øN.…”

“…Kawabe [1988], using 19 years of tide gauge data from Naze (south of the Kuroshio) and Nishinoomote (north of the Kuroshio), found that the only consistent seasonal variation in the Kuroshio is that it reaches a maximum in transport during July and decreases to its minimum in middle to late October. Clifford and Horton [1992] use climatological data to show that the baroclinic transport of the Kuroshio has a broad maximum from late summer through fall and drops to a minimum during spring. Mizuno and White [1983], using average seasonal 300-m temperature maps, investigated seasonal variability in the Kuroshio Extension's meanders and found that the amplitude of two quasi-permanent meanders west of 150øE grew progressively larger from summer to winter but diminished markedly during spring.…”