珠峰地区近50年极端降水变化特征分析

Variability of Extreme Precipitation Events in the Mount Qomolangma Region during the Last 50 Years

基于聂拉木和定日国家气象观测站逐日降水资料,选用世界气象组织推荐的11个极端降水指数,利用多种统计方法分析了1971~2020年珠穆朗玛峰(以下简称珠峰)地区极端降水指数的变化特征。结果表明:珠峰地区全年以中雨日数为主,持续干期远大于持续湿期且北坡更为突出,但珠峰南坡多数极端降水指数年均值和变幅均大于北坡。珠峰地区极端降水指数表现出以减小为主要特征的不显著变化趋势且北坡更明显。珠峰地区极端降水指数突变主要发生在20世纪80年代和90年代。珠峰地区极端降水指数周期差异大,相关性越高的极端降水指数其周期更接近甚至相同。年总降水量除与持续干期呈不显著负相关外,与其它极端降水指数均呈正相关关系,且绝大多数都通过了99%水平的显著性检验,而持续干期则与大多数极端降水指数为不显著负相关关系。

According to the daily precipitation data from Nielamu and Dingri meteorological stations in the Mount Qomolangma region during 1971~2020,the variability of extreme precipitation indexes is analyzed by using different statistical methods.The R10 is the biggest among the R10,R20 and R25,which means the heavy precipitation is the main weather characteristic.The CDD is far greater than CWD,which is more significant in the north slope of the Mount Qomolangma.Most of the extreme precipitation indexes in the south slope are greater than those of in the north slope in the Mount Qomolangma.There is not significant decreasing trend for all the extreme precipitation indexes in the periods of 1971~2020,and the abrupt occurs mainly in 1980s and 1990s.The periodic changes for the extreme precipitation indexes are very different,but the better the correlation between extreme precipitation indexes has,the closer the period would be.In all the extreme precipitation indexes,the PRCPTOT has high correlation with the other extreme precipitation indexes.The results of this research would be helpful for the understanding of the extreme precipitation characteristics in the Mount Qomolangma region,and it also could provide a reference for the Second Tibetan Plateau Scientific Expedition and Research.