北京地区强降水极端气候事件阈值

Study on threshold values with an extreme events of precipitation in Beijing

根据北京地区1951～2008年逐日降水量资料,采用排序法、插值法、正态变换法、平方根变换法和立方根变换法等5种计算阈值的方法,对强降水极端气候事件阈值的确定问题进行研究。研究结果表明,确定日降水量百分位阈值的方法,在5种计算阈值的方法中,平方根变换方法得到最好的效果。在阈值确定的样本中,可以使用30年滑动气候阶段的样本得到的阈值平均值,作为极端气候事件阈值。

Using daily precipitation data for the period of 1951-2008 in Beijing,the study on the threshold values falling above the percentiles of the extreme events of precipitation,and the calculation of the threshold values with five methods,which are sorting,interpolated,normal distribution transformation,square-root transformation,and cube root transformation,are researched in this paper.The results show that the evaluation of the threshold values using the method of square-root translation has the best effect in five methods.The mean of the threshold values on 30-year moving climatic period can be as the extreme events of daily precipitation in climate.