基于元胞自动机模型的河道汇流过程模拟

The Simulation of Channel Flow Process based on Cellular Automation

对河道汇流过程进行模拟可为洪水灾害预警预报提供参考。利用水力水文学方法能很好地模拟河道汇流过程,但需要输入的参数多,运算过程复杂,对数据精度要求高,而且在无资料区流域无法确定河道上断面流量情况下,该方法具有一定局限性。本文将元胞自动机模型与水文模型相结合,构建了河道汇流过程中的元胞自动机模型和产流汇流规则。通过建立河道坡面拓扑关系,利用SCS-CN(Soil Conservation Service-Curve Number)模型逐个计算河道元胞上的坡面入流,并利用曼宁方程模拟河道汇流过程,最后在Arc Engine平台下进行二次开发,实现了河道汇流可视化。本文以厦门市茂林溪流域为研究区,对1997年5月6日至7日的一场降雨进行了模拟。将本文模拟结果与该流域其他学者的研究进行了对比分析,结果表明在输入数据与水文模型参数相同的情况下,本文不仅模拟出每次降雨间隔产生的较小洪峰,并且整场降雨产生的最大洪峰流量精度与时间精度均提高了5倍,可以更准确地模拟河道汇流过程,适用于河道汇流可视化,该模拟可以为洪水灾害预警预报提供一定参考。

Simulating the channel flow process can provide suggestion to flood disaster forecasting and warning. The hydraulics and hydrology model presently used in simulating channel flow process have many disadvantages, for example, many parameters need to be input and the operation process is complex. What is more, there are high requirements for data precision and it is inapplicable to the ungagged catchments where the condition of river section flow is unknown. In this study, the cellular automata model of the overland runoff and channel confluence rules was constructed by combining the cellular automata model with the hydrological model. Through establishing the river slope topology, we used the SCS-CN （Soil Conservation Service-Curve Number） to calculate the slope inflow of each channel cellular. Then, we used Manning equation to simulate river confluence process. In the end, the process was visualized using ArcEngine. The basin of Maolin Creek in Xiamen was taken as a study case, in which the rainfall-runoff process during May 6-7 in 1997 was simulated to conform this model. Compared with other scholars＇ study results, our results can not only simulate the small flood peak in each rain interval but also increase 5 times in the maximum peak flow precision and 5 times in the time precision under the same condition of the input data and hydrologic model parameters. Using the cellular automation can get higher accuracy and it is suitable for channel flow visualization, which can provide reference to flood disaster forecastingand warning.