独立变量频率法计算P—T大气稳定度频率及其误差分析与订正

THE EVALUATION OF THE FREQUENCY OF P-T ATMOSPHERIC STABILITY BY INDEPENDENT VARIABLE METHOD AND THE ANALYSIS AND REVISION OF THE ERRORS

本文把确定大气稳定度的因子:太阳高度角、云量和风速看作相互独立的变量,并用韦伯分布拟合风频,通过计算三个独立变量的频率的方法计算大气稳定度频率。成都地区实例计算表明,该法与传统的P-T法统计结果十分吻合,但却具有所需资料少,计算工作量小等明显优点,通过对该法的误差进行分析,提出合理的订正方法,得出精确的订正结果。并提出更精确的三参数风频拟合设想。通过与传统P-T法比较,指出了传统P-T法风速分级与实测风速整数取值之间的矛盾,给出了切实可行的解决方法。

In this paper, the solar altitude angle, the amount of cloud and the wind velocity, which determine the atmospheric stability, are considered as independent variables, and the frequency of the wind velocity is fitted according to Weibull distribution. The frequency of the atmospheric stability may be obtained by calculating the frequencies of the above three independent variables. From the practical example in Chengdu, it is shown that the result of this method accords well with the P-T method, but only a few data and a little calculation are needed for this method, After analysing the errors of this method, we put formard the plans to revise them. Finally the contradiction between the division value of the wind velocity in the P-T method and the integer value of the practical observed wind velocity is found by comparing this method with the P-T method, and a suggested solution is given.