Meridional mixing of water masses in the Kuroshio Extension: Origins of North Pacific Intermediate Water anomalies

Abstract

[author abstract] Freshwater layers were discovered at intermediate depths north of the Kuroshio Extension front in February 2013. The anomalous layers of freshwater were determined to have originated in the Sea of Okhotsk, where sea ice and vertical tidal mixing create Okhotsk Sea Mode Water (OSMW). OSMW is the coldest and freshest source of North Pacific Intermediate Water (NPIW) and therefore has a unique temperature, salinity and potential density signature. The Argo floats that observed the largest variations in salinity were tracked by GPS in a circular trajectory, which is indicative that they were moving within an eddy, and compared to satellite altimetry of the region.