Kuroshio surface transport from Topex altimetry

The Kuroshio is the warm western boundary current in the Northern Pacific. With surface flows of 1-2 ms^-1, the Kuroshio and its extension transport more than 10¹⁵ W of heat, thereby affecting both regional and global climates. However no consensus exists regarding the Kuroshio´s surface transport and its seasonal variation. The authors examine these using Topex altimeter measurements of sea surface height which are accurate to <5 cm, together with Kelly and Gille´s (1990) `Gulf Stream´ method of determining the geostrophic surface transport of a meandering current jet. They find the absolute surface transport is sensitive to both the type and width of the low-pass filter used to pre-smooth the data (surface transport increasing by up to 25% if the filter width is doubled). On monitoring the seasonality in Kuroshio surface transport at two longitudes (145°E and 153°E) over 21 months they find that the surface transport is correlated with the latitude of the central flow but that the seasonality is different at the two locations