Numerical Evaluation on the Effect of Density Current Generator to Oxygen-Deficient Water in Ariake Sea

We conducted a real-time simulation to numerically reproduce oxygen-deficient water, which appeared in Ariake Sea in the summer of 2001. Furthermore, we set density current generator (DCG) as seawater-quality enhancer and investigated where to put and when to start the DCGs to reduce the ODW. As a result, we found the following mechanism. First, the DCG promotes vertical mixing to raise temperature in the bottom layer. This leads to the increase of phytoplankton and its photosynthesis supplies the oxygen to the bottom. It was also elucidated that the effective way to diminish ODW is to start operating the DCG inside the emergence area a few weeks before ODW appears.