城市暴雨强度公式拟合方法研究

Study on fitting methods for urban storm intensity formula

传统方法确定暴雨强度总公式的参数需要经过理论频率曲线拟合和总公式参数拟合两个环节,但由此法求得的暴雨强度总公式拟合实测雨强样本的误差平方和不为最小。本文采用非线性回归方法,研究了暴雨强度总公式直接拟合实测雨强样本的直接拟合法,使所求总公式拟合实测雨强样本的误差平方和为最小,实现了总公式参数的直接寻优。结合两个实例,对直接拟合法与采用不同理论频率分布的传统方法进行了比较,结果表明,直接拟合法切实可行,不仅使拟合精度提高,而且减少了不同理论频率曲线的选择与拟合环节,可避免推求暴雨强度总公式参数的任意性。

Conventional method for determining the parameters of the storm intensity multi-period formula usually consists of two fitting processes, fitting the theory frequency curve and fitting the parameters of storm intensity multi-period formula. By such way to fit samples of the observed storm intensity, sum of squared error cannot reach the minimum. In this paper, a direct fitting method for storm intensity multi-pe- riod formula has been studied by nonlinear regression to directly fit the samples. With the storm intensity multi-period formula obtained by the direct fitting method, the minimum sum of squared error can be ac- quired in the process of fitting samples of observed storm intensity, and the best parameters are directly es- timated. Combined two examples, the direct fitting method were compared with the conventional methods by using different theory frequency curve. The results indicate that the direct fitting method is feasible, which can increase the fitting accuracy, decrease the processes of choosing and fitting for different theory frequen- cy curve, and avoid arbitrariness of deriving parameters for the storm intensity multi-period formula.