여수 연안 수괴의 계절 변동

Seasonal fluctuation of water mass in the coastal water of Yosu

In order to investigate the seasonal fluctuation of watermass of set net fishing grounds located in the coastal waters of Yosu, oceanographic observations on the fishing grounds were carried out from Jan. to Dec. in 1990. The resultes obtained are summarized as follows; 1. The monthly distribution of water temperature and salinity was from 6.6℃ to 27.0℃ and from 23.0‰ to 33.0‰ at the north entrance of Yosu bay, from 8.5℃ to 27.3℃ and from 27.0‰ to 32.2‰ at the center of fishing ground and from 11℃ to 26.5℃ and from 30.0‰ to 33.4‰ at the outside of Sejondo. The variation width of water temperature in the inner water was bigger than that in offshore water becaus of the inflowing of land water from the Somjin river. 2. The variation of salinity was made high salinity in winter and low salinity in summer. The low salinity(30.0‰) distributed between surface and 10m layer from June to October at the north entrance of Yosu bay. The low salinity distributed between surface and 7m layer from July to September at the center of fishing ground and between surface and 5m layer in August only at the outside of Sejondo. 3. In the surface, at 10m and 20m layer, water temperature changed with same pattern respectively. The variation of salinity was large in summer, and its difference was 6‰ at surface, 4‰ at 10m layer and 1.6‰ at 20m layer. 4. As vertical mixing was made frequently in spring, autumn and winter, the differences in water temperature and salinity between surface and bottom were respectively small. In summer, however, the mixing was not made because the inner water expanded to offshore through the space between surface and 10m layer. But a thermocline of 2.0℃/10m and halocline of 4.0‰/10m respectively in vertical gradient was formed in summer.