The distributions of sea surface temperature across the Cheju Strait and the Korea Strait have been measured by using a thermometer installed on board No.1 Cheju, a ferry that operates regularly between Pusan and Seogwipo. The data from 14 October 1991 to 15 August 1992 were analyzed in this paper. A clear temperature front is formed at the adjacent sea of Geomundo, and its position is not fixed and moves north and south. The slow northward movement of the front can easily be traced, but the southward movement from March to October is obscure. The temperature contrast in the Cheju Strait and the Korea Strait is very weak in this period. Some periodical fluctuations with a period of several tens of days are observed in the region of the temperature front from November to February. This fluctuation seems to be caused by winter heat flux exchange and the strong southeastward wind force. The result shows that continous observation of the sea surface temperature distribution across the Cheju Strait and the Korea Strait yields a good method for monitoring the presence of Tsushima Warm Current and the fluctuations of South Korea Coastal Water. The formation and structure of shelf front in the Cheju Strait and the Korea Strait was analysed based on the detailed oceanographic data observed during the period of 1990-1992. The analysis shows that well-defined fronts were formed through yearly around the Chuja Island, particularly in summer. In nature, its structure and formation position can be changed easily from year to year and by season. But, in region of the Korea Strait this front is relatively weak.

• 양성기 | Sung Kee Yang