津軽海峡西方海域における中深層水の経年変化

概要

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Interannual variation of water-temperature and salinity structures in deep water was investigated by means of CTD data along N-Line (41°50'N, 138°00'E-140°00'E) and S-Line (40°36.5'N, 138°00'E-139°48'E) in spring and autumn from 1988 through to 1995. There were uneven isotherms below the depth of 500m, and the water less than 0.2°C exists relatively shallow region on shore, which seemed to be correlated to the bottom topography. The deep cold water was getting warm slightly throughout the observation period because of the heat conduction from surface layer, since the Japan Sea Proper Water might have not been formed for the last several decades. Comparing the interannual variation of the potential temperature at 500m-depth with the monsoon index, it was found that the water on shore becomes cold in moderate winter and warm in severe winter. It is suggested that the intensity of the convection in the Tsushima Warm Current alters the thickness of the surface layer. Salinity of the High-Salinity Intermediate Water (HSIW) was increasing throughout the observation period, especially in autumn, which indicates that high salinity water might have not been entrained to deep water due to the moderate winter.
Research Institute for Applied Mechanics, Kyushu Universityの論文
2006-03-00