The mixed layer depth in the North Pacific as detected by the Argo floats

The distributions and time changes of the mixed layer in the North Pacific are examined using the Argo floats data. Spatial distribution of the mixed layer depth (MLD) in March reveals that the deep MLDs are concentrated in the northwestern region of the subtropical gyre. Comparing the distribution of MLDs measured by the Argo floats to those based on the climatology, many MLDs detected by the floats in the region north of the Kuroshio Extension are shallower by up to 270 m than the climatology, but south of the Kuroshio Extension the former are deeper by up to 330 m than the latter. Investigating details of the time changes of MLD in selected small areas, both timing and amplitude of the development and retreat of MLD differs remarkably from the climatology in the south of the Kuroshio Extension.