Study on influence of cold-air front on water and sediment exchange between the north passage of the Changjiang River Estuary and adjacent sea areas
In order to investigate the characteristics of water and sediment exchange between the North Passage(NP)and adjacent sea areas in the Changjiang River Estuary(CRE)under cold-air fronts,events of cold-air fronts were statistical analyzed during 20 years.A three-dimensional flow-wave-sediment coupling model was established to simulate the influence of cold-air fronts with varying paths and intensities on the dynamics,suspended sediment,and water and sediment transport between the NP and the nearby sea areas.The results show that the frequency of cold-air fronts affecting the CRE in the east path and middle path is comparable and less than half that observed in the west path.The range of wind speeds during the west-path cold-air fronts is large,with both weak and extremely strong cold-air fronts occurring,while the range of wind speeds during the middle-path and east-path cold-air fronts is small,with cold-air fronts of magnitudes 7 and 8 being dominant.The cold-air fronts significantly increase the bottom shear stress on shallow shoals near the NP and beyond its mouth,increasing the suspended sediment concentration(SSC)in the water.This high-concentration sediment is then transported into the NP by currents,leading to an increase in the SSC of the NP.The influence of cold-air fronts in the west path on water and sediment transport near the NP is obviously weaker than that in the east path and middle path,due to limitations imposed by wind blowing distance.The intensity of cold-air fronts in different paths is always the key factor affecting the SSC and suspended sediment inflow in the NP.With the increase of wind speed,the total sediment inflow in the NP increases significantly.
North Passage of the Changjiang Rivercold-air front pathcold-air front intensitynumerical simulationwater and sediment transport
万方数据
维普
