山东省短时极端强降水研究

利用1999—2011年4—10月全省大监自动站逐时降水观测资料,采用排序法、正态变换法(Z指数法)、平方根变换法等3种计算阈值的方法,计算了山东短时极端强降水的阈值,采用不同方法会得出不同的阈值。传统排序法计算的结果更接近实际,最后采用此法计算结果确定山东省及5个分区短时极端强降水阈值。结果显示:鲁东南、鲁中、鲁西北地区阈值大,鲁西南和半岛地区阈值小,特别是鲁西南地区阈值最小。鲁西北、鲁西南、鲁东南、鲁中和半岛南部易出现短时极端强降水,半岛北部短时极端强降水较少。短时极端强降水出现的偶然性大,极端强降水出现次数与年平均降水量没有明确关系。7、8月是防范短时极端强降水的关键时期。

A Study of Short Range Extreme Heavy Precipitations in Shandong

Using the hourly precipitation data from April to October, 1999 to 2011 in Shandong Province, the threshold values of short term extremely heavy precipitation in Shandong province are defined and calculated with three methods (sorting, normal distribution transformation, and square root transformation). The results show that the thresholds gotten with different methods are significantly different. The threshold values calculated by the sorting method are close to the actual distribution, so the threshold values in the five parts of Shandong Province are defined. The threshold values in the southeast, central, and the northwest parts of Shandong Province are bigger, but those in the southwest and peninsula parts of Shandong Province are lower, especially that in the southwest is the lowest. Short term extremely heavy precipitations appear frequently in the northwestern, southwestern, southeastern, and central Shandong Province, as well as the southern Shandong Peninsula, but rarely occur in the northern Peninsula. Short term extremely heavy precipitations are not necessarily related to the annual mean precipitation and often happen accidentally. The right measures should be taken for short term extreme heavy precipitations, especially in July and August.