Dynamic Simulation Of Soil Water Content Based On CA

The possibility of benggang erosion is the key issues that need to be resolved in the early warning and prediction.In order to provide a reference to early warning and forecasting of the possibility of benggang,this study starts from the basic theory of cellular automata(CA)and the factors affecting soil moisture content.Through the basic structural design and functional design of CA model,a dynamic simulation model of soil moisture based on CA is constructed.The model parameters were determined using the data of soil moisture after rainfall in the Hou Gong area of Longmen Town,Anxi County,and the model was verified.The Nash coefficient NSE was equal to 0.6,the average absolute error R was 3.58%,and the reasonable rate was 77.59%,each model accuracy requirements.Finally,five kinds of rainfall scenarios were set up to simulate the soil waters content of Xixi River in Anxi County,and the result map was output in the MATLAB software to obtain the simulated maps of soil moisture content under different rainfall intensity and duration,and visually express the dynamic information of the key factor of collapsing,soil moisture content.The main conclusions are as follows:(1)The CA method can effectively simulate the dynamic changes of soil water content in a catchment.The change of soil moisture content is influenced by many factors,is extremely complex,and presents a nonlinear relationship.However,CA uses simple local rules to simulate extremely complex geospatial things.Therefore,CA method can well solve the dynamic change of simulated soil water content.In this study,the CA model was constructed by designing two conversion rules and determining six parameters.It can be seen from this that there are fewer model parameters in this study and the model structure is simple,which greatly reduces the difficulty of model designed.(2)The dynamic change of soil water content in the catchment was simulated by constructing the CA model.The CA model was built based on MATLAB software programming and compared with the soil moisture data in the study area.The Nash coefficient NSE was equal to 0.6,the average absolute error R was 3.58%,and the reasonable rate was 77.59%.The results show that the constructed CA model can better simulate the dynamic changes of soil moisture content.(3)Through the simulation of different rainfall scenarios of the Xixi Watershed in Anxi County,we can see that the change in soil moisture content is not only related to the rainfall intensity,but also related to the rainfall duration,mainly because the rainwater will continue to infiltrate into the action of the water gradient when entering the soil,and the infiltration process will also as time go by,it slows downs.However,when the rain on the local surface is continuously replenished,the water in the soil will continue to infiltrate,causing the wet front to continuously move downwards.From the scenario simulations,the soil moisture content around the residential area is the highest,while the soil moisture content in the mountainous area is low.Mainly because of the human activities in the area,vegetation is destroyed,a large number of excavated soils,resulting in soft soil,no vegetation protection on the surface,rain more easily into the soil.In the woodland area,the soil moisture content is relatively low.On the one hand,vegetation has a function of trapping rainwater,which prevents a certain amount of rainfall from reaching the ground.On the other hand,forest lands are generally distributed at high altitudes.Due to the influence of topography,some rainwater will flow to low-lying areas along with topographic changes.