站点特征及插值方法对山地城市面雨量推求的影响

Influence of station characteristics and interpolation methods on areal rainfall calculation in mountainous cities

面雨量是考虑降雨空间异质性下城市降雨径流模拟不可或缺的输入数据,而面雨量推求与雨量站点特征、推求方法以及地形等因素密切相关。为量化分析雨量站点特征和空间插值方法对面雨量推求的影响,以典型山地城市重庆市为例,设置6种站点密度,利用最邻近指数评价站点空间特征,并探究6种空间插值方法对城市不同降雨等级下面雨量计算的适用性。结果表明:随着雨量站点密度增大,面雨量推求误差呈下降趋势,且降雨等级越高,雨量站点密度对面雨量推求的影响越显著;当雨量站点数量小于25时,面雨量模拟误差基本呈现随站点空间分布均匀程度增大而增大的趋势,但当站点数量达到25后,站点分布越均匀,误差越小;东北部山区面雨量采用反距离权重法和径向基函数法模拟时误差较小,而普通克里金法对东南部面雨量模拟更为准确,从降雨空间分布特征的表现能力来看,径向基函数法是最适宜重庆市的面雨量插值方法,尤其在山区表现出良好的模拟效果。研究成果可为不同降雨等级下雨量站点数据和面雨量推求方法的选择提供参考。

Areal rainfall is an indispensable input data for urban rainfall runoff simulation,considering the spatial heterogeneity of rainfall.And areal rainfall is closely related to rainfall station characteristics,calculation methods,and topography.To quantify the influence of rainfall station characteristics and spatial interpolation methods on areal rainfall calculation,Chongqing City,a typical mountain city,was selected as the study area,and six densities of rainfall stations were chosen.The spatial characteristics of rainfall stations were evaluated using the nearest neighbour index,and six spatial interpolation methods were used to assess their suitability for rainfall interpolation across different grades of precipitation.The results showed that with the increasing density of the rainfall stations,the error in areal rainfall calculation decreased.As the rainfall grade increased,the influence of rainfall station density on areal rainfall calculation became increasingly significant.When the number of rainfall stations was less than 25,the simulation error generally increased as the uniform spatial distribution of stations increased.As the number of rainfall stations reached 25,the more evenly station distributed,the smaller errors was.The Inverse Distance Weighted method and Radial-Basis Function method had less error in simulating areal rainfall in the northeastern mountains,while the Ordinary Kriging method was more accurate for simulating areal rainfall in the southeast.From the perspective of the describing ability of spatial distribution characteristics of rainfall,the Radial Basis Function method was the most suitable method for interpolation of areal rainfall in Chongqing City,especially in the mountainous areas.The results will provide a reference for selecting rainfall station data and areal rainfall calculation methods under different rainfall grades.