Warm and saline water transport to the North Pacific subarctic region: World Ocean Circulation Experiment and Subarctic Gyre Experiment data analysis

Abstract

A warm and saline water transport to the North Pacific subarctic region which could feed the mesothermal (intermediate temperature maximum) water is investigated through the analysis of World Ocean Circulation Experiment and Subarctic Gyre Experiment hydrographic data. The analysis of individual cruise data supports the hypothesis that warm and saline water is transported from the area east of Japan to the Gulf of Alaska and also indicates that the isopycnal mixing is active in the area east of 165°E. The transport route obtained from individual cruise data mostly agrees with that based on climatological data. As a whole, isopycnal potential temperature and potential vorticity are conserved along the transport route using both the climatological and individual data excepting that the potential vorticity at 26.8σθ rapidly increases along streamlines in the Gulf of Alaska when the climatological data are used. This discrepancy might be attributed to the existence of the strong potential vorticity front in the Gulf of Alaska and excessive smoothing in the climatological data.