Diurnal sea surface temperature warming along the Kuroshio off Taiwan under easterly wind conditions

Abstract

We carry out the Lagrangian diurnal warm layer (DWL) observations, supplemented by satellite products, along the strong Kuroshio east of Taiwan, where the boundary terrain modifies the winds and the advection effect is significant. The synoptic easterly wind bifurcates as it encounters Taiwan's coast, forming the southward-blowing and the northward-blowing branches in the southern and northern regions of the bifurcation, respectively. The two branches produce areas with enhanced and weakened apparent wind speed relative to the northeastward flowing Kuroshio. The DWL can reach 5 m in the south of the bifurcation due to the shear instability-induced mixing. Sea surface temperature (SST) enhancement occurs around and in the north of the wind bifurcation, where the solar heat is only trapped in the upper 2 m due to the absence of instability, forming inhomogeneous SST along the Kuroshio. The synoptic wind variations and Kuroshio advection further modulate the location of SST enhancement.