阿勒泰地区5—9月极端干期长度的概率特征分析  

An Analysis on Probability of Extreme Drought Period from May to September in Altay Region

作　　者：张林梅[1,2] 黄阿丽[2] 李海花[1,2] 庄晓翠[1,2] 

机构地区：[1]中国气象局兰州干旱气象研究所,甘肃兰州730020 [2]阿勒泰地区气象局,新疆阿勒泰836500

出　　处：《沙漠与绿洲气象》2011年第6期27-31,共5页Desert and Oasis Meteorology

基　　金：兰州干旱气象科学研究基金项目(IAM200914);新疆气象局项目"阿勒泰地区气候变化与干旱研究"(201014)

摘　　要：利用新疆阿勒泰地区7个测站1961—2009年逐日降水资料,统计5—9月连续无降水日数(日降水量<0.1 mm),得到该地区5—9月极端干期长度。分析近49 a平均极端干期长度的空间分布特征、趋势变化及其与同期降水量的关系,并采用概率加权(PWM)估计其分布函数的参数,从而给出该地区50 a一遇极值分布及≥20 d的极端干期概率分布。结果表明:阿勒泰地区近49a极端干期长度的平均值及标准差的分布均为自北向南、自东向西递减,且极端干期与5—9月总降水量均呈显著负相关。极端干期趋势分析表明,该地区大部分站(除福海及布尔津站)呈现缩短趋势,尤其吉木乃和富蕴站通过了显著性检验。该地区极端干期50 a一遇极值及≥20 d的极端干期的概率分布,均是自东向西,自北向南递减。Based on the daily precipitation data of 7 stations from1961 to 2009 in Ahay region, we calculated the continuous days without precipitation （daily precipitation less than 0.1mm） and obtained the length of extreme drought period from May to September. We analyzed its spatial distribution, change trend, and relationship with contemporaneous precipitation in the recent 49 years,estimated the parameters of distribution function by the method of probability weight （PWM）, and then gave the extreme drought distribution of 50-year frequency and the probability of I〉20 d extreme drought. The results showed that the mean value and standard deviation of extreme drought period in Altay region decreased from north to south, from east to west, and the extreme dry period showed significant negative correlation with total precipitation from May to September. The trend analysis for the extreme drought period indicated that most stations （except Fuhai and Buerjin stations） shortened,especially drought of 50-year frequency and the probability north to south, from east to west. Jimunai and Fuyun. The distribution of extreme of≥20 d extreme drought both decreased from north to south, from east to west.

关 键 词：极端干期长度 Gumbel分布 概率加权估计法 Mann—Kendall趋势检验法 

分 类 号：P468[天文地球—大气科学及气象学]