Numerical Study on the Hydrological Change due to Water Level Rising in the Caspian Sea

In the Caspian Sea, the deterioration of the ecosystem has been increasingly worried due to the development of offshore oil and natural gas resources. In addition, the rising of water level causes the oil leakage from the coastal old oil well and changes the water current, resulting in an uncertain dispersion of oil pollutants. In the present study, the change in the fields of water current was discussed by using a three- dimensional numerical model called MEC (marine environmental committee) Ocean Model, which was developed by the Japanese Society of Naval Architects and Ocean Engineering. As a result of verification of the numerical model the stronger current was found along the southeast coast of the Caspian Sea, while the remarkable jet-like structure was not found in the shallow waters. If the horizontal distribution of wind stress was taken into account, the cyclonic circulation found in the middle of the Caspian Sea was reproduced in February- However, it should be noted that the basic feature of the water current field is also based on the density-driven current due to the surface heat flux and the inflow of rivers. Finally, the effects of the change in the bathymetry due to water level rising and of the Kara Bogaz Gol were negligible, while a lot of Caspian water may flow into the Kara Bogaz Gol and the basic current field may be changed in the Caspian Sea if the water current directs eastward due to the wind stress. The present study is the first step of the numerical study on the Caspian environment. As future studies, high resolution of grids, density-driven current, and a lower-trophic ecosystem model will be taken into account in the numerical model.