Dandong bay, as a study area, is a part of the Jinhae Bay, which is located at onshore of southern Korea peninsula. Its depth is less than 18m and has poor circulations due to the semi-closed landform, leading to forming hypoxia frequently from May to October. In order to analyze how hypoxia is related with physical-biochemical water properties changes and to determine the critical threshold for predicting the hypoxia conditions in Dandong bay, two datasets were analyzed based on statistical and regression analysis. One is 13 different stations of physical-biochemical water measurements from January to October in 2016. The other dataset is those of real time observations from August to October in 2016. The hypoxia begins at the central bay at Station 12 following by the outer bay at Station 7, suggesting that different physicalbiochemical processes play an important role in the bay. Since vertical stratification is the most important physical forcing to form hypoxia, density differences between surface and bottom layer were estimated and compared with DO concentrations. For inner bay, density differences and DO had negative relations and its ranges were from 1.8 to 3. For outer bay, the relations were positive and its threshold was about 5.2. These result imply that the conditions for forming hypoxia in Dandong bay can be controlled by not only physical forcing, but also biochemical processes in the bay water.
1. Analysis based on individual data
2. Analysis based on interpolated data
3. Analysis based on real time data