Divergent eddy heat fluxes in the Kuroshio Extension at 144°-148°E. Part I: Mean structure

The mapped EHF estimates agreed well with point in situ measurements from subsurface current meter moorings. Geostrophic currents determined with the CPIES separate the vertical structure into an equivalent-barotropic internal mode and a nearly depth-independent external mode measured in the deep ocean.

As a useful by-product of this decomposition, the divergent EHF (DEHF) arises entirely from the correlation between the external mode and the upper-ocean thermal front. EHFs associated with the internal mode are completely rotational. DEHFs were mostly downgradient and strongest just upstream of a mean trough at ~147°E. The downgradient DEHFs resulted in a mean-to-eddy potential energy conversion rate that peaked midthermocline with a magnitude of 10 × 10⁻³ cm² s⁻³ and a depth-averaged value of 3 × 10⁻³ cm² s⁻³.