雅鲁藏布江流域极端降水模拟及预估  

Extreme precipitation simulation and forecast of the Yarlung Zangbo River basin

作　　者：高佳佳 杜军[1,2,3] GAO Jiajia;DU Jun(Lhasa Branch of Chengdu Institute of Plateau Meteorology,China Meteorological Administration,Lhasa 850000,China;Tibet Institute of Plateau Atmospheric and Environmental Science,Lhasa 850000,China;Tibet Key Laboratory of Plateau Atmospheric and Environmental Science Research,Lhasa 850000,China)

机构地区：[1]中国气象局成都高原气象研究所拉萨分部,西藏拉萨850000 [2]西藏高原大气环境科学研究所,西藏拉萨850000 [3]西藏高原大气环境研究重点实验室,西藏拉萨850000

出　　处：《冰川冻土》2021年第2期580-588,共9页Journal of Glaciology and Geocryology

基　　金：国家自然科学基金项目(41765011);2019年西藏自治区科技重点研发计划项目“西藏主要地表特征科学考察及研究”;西藏自治区自然科学基金项目(XZ-2019ZRG-150)资助。

摘　　要：为了解雅鲁藏布江流域汛期极端降水的变化规律,推算一定重现期的极端降水量分位数,通过百分位法、Hill图法、年交叉率法选取阈值,借助广义帕累托分布函数(GPD)对流域极端降水频率进行了分析。结果表明:99百分位时的阈值为流域内各站点的最佳阈值,且各站点超阈值序列通过了M-K的平稳性检验,无明显突变。拟合效果通过K-S检验,各站点拟合的极端降水理论频数和实测频数基本相符。尺度参数的大值区位于流域下游,表明该地区的极值波动大;形状参数正值区位于流域中上游地区,说明发生破纪录降水事件的概率较大,拟合结果与实际观测一致。从5年一遇和10年一遇的极端降水值来看,雅江流域除拉孜站外,其他地区降水极值均超过30mm,日喀则地区的降水极值达50mm;各地区20年一遇和30年一遇的降水极值增长的非常缓慢。通过与实际极端降水值对比分析得出,GPD拟合计算出的重现期水平基本符合实际,即具有一定的合理性。In order to understand the variation law of extreme precipitation in flood season of the Yarlung Zangbo River basin,the quantile of extreme precipitation in a certain recurrence period was calculated by generalized Pareto distribution(GPD)method. The results indicate that the threshold at the 99 th percentile was the optimal threshold for all stations in the basin. The super-threshold sequence of all stations passed the stationarity test of M-K and without an obvious mutation. The fitting effect passed K-S test,and the theoretical frequency of extreme precipitation fitted at each station was mainly consistent with the measured frequency. The large values of the scale parameters were located in the downstream of the basin,which indicates that the extreme values fluctuate considerably. The positive area of shape parameters was located in the middle and upper area of the basin,which indicates that the probability of record-breaking precipitation event was relatively high. The fitting results were consistent with the actual observations. According to the extreme precipitation values that occur once every 5 years and once every 10 years,except for the Lhaze station,the extreme precipitation values in other regions of the Yarlung Zangbo River basin exceed 30 mm,and the extreme precipitation values in Shigatse region reach 50 mm. The precipitation extremes that occur once in 20 years and once in 30 years increase very slowly in all regions. In comparison with the actual observation,it can be concluded that the level of recurrence period calculated by GPD fitting was basically in line with the reality and has certain rationality.

关 键 词：雅鲁藏布江流域 广义帕累托分布 极大似然相似 极端降水 重现期 

分 类 号：P458.1[天文地球—大气科学及气象学]