Based on monthly and annual precipitation at 81 stations from 1951 to 2010 in Gansu Province, the normality of the observed precipitation and the precipitation series from Box - Cox transformation was analyzed by using Jarque - Bera test and the test of chi -square, respectively. The results show that annual precipitation followed the normal distribution at most of the stations but the monthly precipitation didn' t obey that at half more stations, and in December, November, January the precipitation normality was worst and in May and September it was best. The normality was good in spring and summer but bad in fall and winter at most of stations. The precipitation exists non - normality in all Gansu Province, especially in the Hexi Corridor region, the center and east region of Gansu. Compared with the original series, the pass rate of normality about annual precipitation increased from 81. 5% -82. 7% to 97. 5% -100% and monthly precipitation increased from 36. 2% -68.5% to 85.4% -94.0% through the Box - Cox transformation, and most of stations followed the normality test.%利用1951 ～2010年甘肃省81个气象站月、年降水量资料,采用Jarque-Bera检验与x2检验对原降水序列和经过Box-Cox变换后序列的正态性进行分析.结果表明:甘肃省大多数气象站年降水量服从正态分布,但一半以上台站的月降水不服从正态分布.其中12月、11月、1月的正态性最差,而5月和9月最好；从季节来看,甘肃大多数气象站春、夏季正态性较好,秋、冬季正态性较差；从地域分布来看,全省各地降水均存在非正态,其中河西地区、陇中和陇东部分站点非正态现象尤其突出.经过数据变换后的序列,站年正态性通过率从原来的81.5％～82.7％升高到97.5％ ～ 100％,站月通过率从36.2％ ～68.5％升高到85.4％ ～ 94.0％,大部分站点通过了正态性检验.
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