대한해협 저층냉수의 유입에 미치는조석의 영향에 관한 수치실험

Abstract

The Korea Strait Bottom Cold Water (KSBCW) indicates lower than 10 ℃ of sea water observed in the Western Channel of the Korea Strait. The intrusion of KSBCW is maximum in Summer (August or September) and second maximum in Winter (December or January). However, its mechanism and origin is not revealed yet.

This study investigates mechanisms of KSBCW intrusion using 3-dimensional high resolution ocean circulation model and focuses on effects of tides. ROMS(Regional Ocean Model System 3.4 version) is used for ocean model and study area covers the Korea Strait and part of East Sea, 126.9-132°E and 33.3-36.5°N.

Two experimental cases(considering tides or not) were compared. It could be seen that results from experiment involving tides showed better agreement with the observed temperature and velocity. Tides act to enhance the intrusion of KSBCW.

Additionally, we study main factors to simulate KSBCW intrusion in numerical ocean model. Firstly, we find semi-diurnal constituents (M2, S2) play important role in generating the intrusion of KSBCW. Because the amplitude of semi-diurnal tidal waves are larger than diurnal tidal wave(K1, O1), deep and cold water in the Ulleung Basin can flow into the Korea Strait. Secondly, numerical models need to exhibit bathymetry of the western channel trough to simulate KSBCW intrusion, which is associated with the resolution of model. After the cold waters in the Ulleung Basin cross over the Korea Strait shelf break, it flows along the Western Channel bottom slope.