The 3-D Suspended Particulate Matter Model And Its Application To The Mouth Of The Huanghe River

More and more attention is paid to the transportation of suspended particulate matter in the sea with the development of ecological and sedimentary dynamics. However more attention is paid to 2-D simulations of the SPM transportation, and less research is done for the vertical direction's simulation. This paper establishes the SPM vertical distribution model with the bottom current near the mouth of Huanghe river. Then an existed 3-D suspended particulate matter model is improved by the result of the vertical simulation and the SWAN model is used to provide the wave for it. The SPM transportation near the mouth of Huanghe river under the condition of Huanghe river' water decrease is simulated by the model.Firstly a 1-D vertical tracer model is developed only considering the process of the vertical movement of SPM in the water body and the deposition and erosion processes at the sea bed. One set of in situ data near the mouth of Huanghe obtained in 2000 is used to check this 1-D model. The result shows the simulation is consistent with the real case, which means the model can simulate the vertical SPM distribution. At the same time some parameters in the 1-D model is analyzed: higher vertical turbulent diffusivity makes stronger diffusion in the high SPM concentration field; the big value of the critical settling velocity is helpful for the deposition; the value of critical erosion velocity has a range the erosion process depend on it. The selection of critical erosion and settling velocity suggests the deposition and erosion processes have an great effect on the SPM transportation.In this paper SWAN model is used as the input of wave field for the 3-D suspended particulate matter model to replace the original experiential wave formula. A case in 1999 is used to calibrate the SWAN model, and the result is satisfactory.Then SPM distribution in the Bohai Sea in 2000 is simulated by the model with result consistent with the observation results. Furthermore, the vertical distribution of SPM at one point is studied here. The result shows not only deposition and erosion at the bed but also the advection process has an great effect on the SPM concentration. The advection process is especially obvious at the area with horizontal SPM concentration gradients.The SPM distribution near the Huanghe River Mouth area is also simulated considering the present case of Huanghe water shortage. The result shows higher SPM concentration appears around the mouth of Huanghe river, which is due to the stronger erosion process. The result also show the north of Huanghe River mouth is eroded heavier than the south east.