Research On Ecological Mathematical Model Of Red Tide And Its Application In Bohai Sea

The damage caused by red tide has been concerned by people. Red tide is not only threating the existence of the marine organism and hazarding the ecological environment of the ocean, but also bringing dangers to people's health and safety. Through studying the formation factor and classification of red tide, discussing the occurrence regulation , especially through studying the numerical simulation of red tide, forecasting it in time and accurately, has a great significance to master the occurrence,development regulation and to reduce the disaster of red tide .In this dissertation,starting from N-S equation, the author derived incompressible fluid depth-integration two-dimensional shallow water circulation equations and established two-dimensional hydrodynamic mathematical model on basis of it;. Deduced plane two-dimensional diffusion equations. Adopted the ADI (Alternating Direction Implicit) Method to disperse and solve the incompressible fluid depth-integration two-dimensional shallow water circulation equations, then a hydrodynamic mathematical model was established. And based on adopting windward format, the plane two-dimensional diffusion equations were dispersed. At last, an ecological mathematical model of red tide was built up by combining hydrodynamics with biodynamics.In this dissertation the author first applied the two-dimensional hydrodynamic mathematical model to the area of Bohai Sea and the north of Huanghai Sea, simulated the tide field and obtains a tide process as boundary condition of Bohai Sea. Then applied the two-dimensional ecological mathematical model of red tide to Bohai Sea, simulated the actual Phaeocystis red tide instance which occurred on 11th~16th June, 2004.Some remote sensing photos of Bohai Sea, which were shot by EOS/MODIS secondary planet on June, 2004, were collected from Meteorolagical Lastitute of Tianjin. These photos were disposed, and many information about red tide, such as the area of red tide, was got from it. In order to validate the model, the area of red tide calculated from the mathematical model was compared with that got from photos.Based on the results calculated by using the ecological mathematical model of red tide, many information such as algae's density and the concentration of nutrient material was obtained .The process of the increase and decrease of red tide was simulated. The establishment of the ecological mathematical model of red tide is not only propitious to the research of red tide occurrence mechanism, but also help to provide a scientific basis for red tide forecast of Bohai Sea.