Kuroshio Inferred from SSTs

Twenty years of ship-injection temperatures are averaged annually and plotted against longitude in the western tropics of the North Pacific. Centered at 150E at both 20N and 25N is a large-scale longitudinal maximum in sea surface temperature. The simplest in-terpretation of this permanent feature is that a continuous flow of warm surface water out of the south is required to maintain it, since some heat will escape into the atmosphere in transit. It is concluded that the northward flow is the Kuroshio.