Observations of the Kuroshio Extension by an Autonomous Microstructure Float

摘要

The Kuroshio carries tremendous volume of water andtransports large amount of heat, organic and inorganicconstituents, impacting climate, storm tracks, and oceanecosystems. The strong current of the Kuroshio is inherentlyassociated with its frontal structures, with across frontalvariations in temperature and salinity. Mixing of these waterproperties could lead to formations of new watermasses, whichcould be subducted to ocean interior at fronts (Rudnick 1996;Nurser and Zhang 2000). Several studies have suggestedthat the Gulf Stream, a western boundary current in the NorthAtlantic, is a nutrient stream which transports nutrients fromtropical ocean to subpolar regions in its subsurface layers(Pelegri and Csanady 1991; Pelegri et al. 1996). Recent studieshave shown that the subsurface current of the Kuroshio is alsoa nutrient stream in the North Pacific (Guo et al. 2012 and 2013)similarly to the Gulf Stream. Stirring and mixing along the pathof the Kuroshio, from the Kuroshio origin, its main stream offJapan coast, and the Kuroshio Extension, could, therefore,play important roles not only for physical oceanography andair-sea interactions but also for biogeochemistry.