Water characteristics and circulation of the upper portion of the Japan sea proper water

On the basis of hydrographic data obtained from 1967 to 1971, the density structure and distributions of water properties on the upper portion of the Japan Sea Proper Water (UJSPW) are investigated. The UJSPW can be defined as having a σ₁ (potential density referred to the 1000 db) range of 32.00-32.05 kg m^-3. A mode water with a pycnostad of more than 300 m in thickness for the σ₁ range of 32.03-32.05 kg m^-3 is common to the western region between 40° and 43° N. This pycnostad coincides with homogeneitis of δ₁ (potential temperature referred to 1000 db), dissolved oxygen and phosphate. It is suggested that the UJSPW is formed by winter time convection in the western region, probably off the Siberian coast west of 136° E between 40° and 43° N, and advects southward to southwestward. The UJSPW largely enters the southwesternmost region of the basin west of the Yamato Rise. A part of the water reaching 40° N or further south turns clockwise along the northern periphery of the Rise and enters the Yamato Basin.