A three-dimensional ecosystem model is applied to the Suyoung Bay, located at the southeastern part of Korea, to study of the material distribution in the time scale of several tens days. The model has included of the DIN(Dissolved Inorganic Nitrogen), DIP(Dissolved Inorganic Phosphate), phytoplankton, zooplankton and detritus, and also was coupled with the physical processes. The spatial distribution of chlorophyll-a and primary productivity in the model is determined by the physical and chemical-biological parameters. The horizontal distributions of the DIN, DIP and chlorophyll-a are decreased from the coast to the off-shore, though the nutrients show some more complicated pattern than the chlorophyll-a. The nutrient contents in the off shore are low, and thus a relatively low productivity(chlorophyll-a) are presented. On the whole, the distribution of the results of model are smoother than the observed ones and some small scale variation in the observed data cannot be reproduced by the model due to the resolution limits of model. However, the basic pattern and the quantitavities has been reproduced by the model well.

The volume transport and turnover time of the Deukryang Bay, located at the southern area of Korea, were calculated based on the current meter(RCM-7,ACM 16M) data observed at the three gateways of the Bay in May and October of 1996. Dominant tidal current component was calculated through harmonic analysis from raw data to estimate influence tidal current and also residual current was measured by integrating observed data and then averaging on time. Maximum speed of current was about 100㎝/sec during the spring tide at the waterway between Kumdangdo and Kogumdo. The total water volume transports through three entrances of the bay in May and October were 3.9×10^-2 Sv, 3.4×10^-2 Sv(1Sv=10^6㎥s^-1) and turnover time were 0.97day, 1.12day, respectively. Semidiurnal tides were predominant (70∼85%). The water volume transports by residual currents were 2∼4% of total water volume transports. The average fraction of fresh water calculated by tidal prism method using salinity difference between inflow current and outflow current through three entrances in Deukryang Bay was about 0.06% of total volume and the flushing time of fresh water was estimated as 0.97day.

The spatial characteristics of stratification in Deukryang Bay were studied using observed data and analytical models. From the description of the density structure and its the potential energy anomaly (PEA) from observed data along longitudinal direction (from the mouth to head of the bay), we found that the stratification intensity could be changed strongly by density current effect during the spring-neap tidal cycle, and depth variation. To find out density current effect for the formation of the stratification in detail, we implemented a diagnostic approach by using the modified analytical model including density current, tidal current, surface heating and wind stirring. The model allowed for the observed similarities for the whole domain in the bay and increased tidal mixing efficiency value ε up to 0.006 - 0.007 as compared to the results without density current effect. We found that the density current effect was also an important key factor in determining the formation of the spatial distribution of stratification.

Surface heat budget of the Deukryang Bay from July 1, 1992 to September 12, 1993 is analyzed by using the meteorological data (by Changhung Observatory and Mokpo Meteorological Station) and oceanographical data (by Research Center for Ocean Industrial Development, Pukyong National University). Each flux element at the sea surface which has annual variation is derived with application of an aerodynamical bulk method and empirical formulae. The solar radiation is the maximum in spring and summer, and the minimum in autumn and winter. The effective back radiation, the latent heat and the sensible heat are the maximum in autumn and winter, and minimum in summer. The heat storage rate is calculated by using the rate of water temperature variation according to the depth. The oceanic transport heat is estimated as a residual. The net heat flux, the heat storage rate are positive in spring and summer, while they are negative in autumn and winter. The oceanic transport heat is convergence in winter and divergence in the rest of seasons.