短时强降水条件下山洪流域面雨量的计算方法——以巴彦淖尔市阴山山脉为例
Calculation of Basin Areal Rainfall in Mountainous Areas under Short-Time Heavy Rainfall: Taking Bayannur Yinshan Mountains as an Example
中文摘要：
巴彦淖尔市阴山山脉地区，群山错列，沟壑纵横，其中洪水危害比较严重的山洪沟道有104条，这些山沟纵坡大、流程短，危害严重，防洪预警能力亟待提升。本文针对巴彦淖尔市阴山山脉地区的特殊地理特点提出了一种山洪沟流域面雨量的计算方法，用于预警当地山洪的发生。山洪沟流域面雨量的计算取决于两个关键技术，一是流域边界的提取，二是流域格点雨量的计算。对于山洪流域的提取，使用多流向DINF算法形成山洪流域面矢量数据。对于格点雨量的计算，采用按距离分配权重的插值方法，将自动气象站雨量内插到1.0 km网格点，然后将山洪沟流域面矢量和格点雨量求交集，计算得到流域面雨量。用流域面雨量的大小做出山洪发生的预警。同时，我们发现山洪形成过程受到瞬时降水强度、山体植被情况以及瞬时下渗强度等多种因素的影响和制约，是一个非常复杂的非线性过程。因此流域面雨量用于山洪预警发布时，还需要结合当地流域内的水文、地理、隐患点等情况综合决策。本文针对一次有人工观测的山洪实例，对西乌盖沟和东升庙沟洪水的流域面雨量进行模拟，验证了所提出流域面雨量计算方法的可用性。
中文关键词：
面雨量，DINF算法，短时强降水，山洪预警
KeyWords：
areal rainfall, DINF algorithm, short-time heavy rainfall, flash flood warning
Abstract：
In the Yinshan Mountain area of Bayannur, mountains are staggered and gullies are crisscross, among which there are 104 mountain flood gullies with serious flood hazards. These gullies are featured with large longitudinal slopes, short flow paths and serious hazards, and hence the flood prevention and early warning capacity needs to be improved promptly. This paper proposes a method for calculating the areal rainfall of mountain flood gullies so as to predict and warn the occurrence of mountain flood. The calculation depends on two key technologies. The first is the extraction of the boundary of the mountain torrent basin, and the second is the calculation of grid rainfall. For the former, we use the multi-flow DINF algorithm to generate surface vector data for flash flood basins. As for the latter, we use the interpolation method of distributing weight according to distance to interpolate the rainfall of the automatic weather stations to the 1.0 km grid point. The watershed areal rainfall can be calculated by intersection of the watershed areal vector and the grid rainfall. And hence the early warning of mountain flood can be determined by the amount of the areal rainfall. Meanwhile, it is found that the formation process of flash flood is affected and restricted by many factors, such as instantaneous rainfall intensity, mountain vegetation and instantaneous infiltration intensity. It is a very complex nonlinear process. Therefore, when the basin areal rainfall is used for the release of mountain flood warning, it is also necessary to make a comprehensive decision in combination with the hydrology, geography, hidden danger points and other conditions in the basin. This paper simulates the basin areal rainfall for the flood in Xiwugaigou and Dongshengmiaogou based on one case of mountain torrent with manual observation, and verifies the applicability of the basin areal rainfall calculation method proposed in this article.