Quantifying the Water Contribution of Subtropical Mode Water and Related Isopycnal/Diapycnal Water Mixing in the Western Pacific Boundary Current Area Using Radiocesium: A Significant Nutrient Contribution From Subtropical Pacific Gyre to the Marginal Region

Abstract

Subtropical mode water (STMW) promotes material exchange by water mixing, through such means as turbulence or advection, and affects ecosystems in the Northwest Pacific. STMW is defined as a water mass, with potential temperature (θ) of 16°C-19°C, potential density (σ θ ) of 25-26 kg m −3 , and low potential vorticity. This water mass property is widely observed in the region of 128°-175°E and 18°-34°N in the North Pacific Subtropical