1961-2010年西北干旱区极端降水指数的时空变化分析  

Temporal and spatial variability of the extreme precipitation indices over the arid regions in Northwest China from 1961 to 2010

作　　者：王少平[1,2] 姜逢清[1] 吴小波[1] 胡汝骥[1] 

机构地区：[1]中国科学院新疆生态与地理研究所,新疆乌鲁木齐830011 [2]中国科学院大学,北京100049

出　　处：《冰川冻土》2014年第2期318-326,共9页Journal of Glaciology and Geocryology

基　　金：国家自然科学基金项目(41171378);国家重点基础研究发展计划(973计划)项目(2010CB951001)资助

摘　　要：结合绝对阈值和百分位法定义极端降水事件的优点,提出了一种更灵敏的检测极端降水事件的方法.该方法不仅能检测出常用降水指数无法检测到的降水量稀少地区尤其干旱区的极端降水事件,同时也能过滤掉其检测到的降水量丰富地区的虚假极端降水事件.此方法首次被应用于统计1961年1月至2010年2月西北干旱区72个气象站点的年和季节的极端降水指数(大降水和强降水指数),并分析了极端降水指数的时间变化趋势及其空间分布特征.结果表明:西北干旱区春(3-5月)、秋(9-11月)、冬(12月至次年2月)三季极端降水指数无显著(P>0.05)变化趋势,夏季(6-8月)大降水的频率和降水量以及大降水降水量占总降水量的比重都显著增加;新疆地区极端降水指数为增加趋势的区域基本都分布在海拔较高(约海拔1 000 m以上)的地区;西北干旱区东部极端降水指数变化趋势的空间分布有明显的季节差异,表现为夏、秋季大部分地区为增加趋势,冬、春季大部分地区为减小趋势.The advantages of absolute threshold and the percentile method are combined to devepl a new method to detect extreme precipitation events more sensitively. Compared with the commonly used method, the new method not only can discover extreme precipitation events in arid region, but also can filter out the fake extreme precipitation events in rich-precipitation regions. This method is firstly used to calculate the extreme precipitation indices, heavy and intense precipitation indices at the level of year and season for the selected meteorological sta- tions in the arid regions of Northwest China, based on the daily precipitation data from January of 1961 to Febua- ry of 2010, then the change trends of calculated extreme pracipitation indices and their spatial distribution charac- teristics are revealed. The main conclusions are as followings. First, the spring （ March to May）, autumn （ September to November） and winter （December to next February） extreme precipitation indices do not change sig- nificantly （ P 〉 0.05 ）, but in summer （ June to August）, precipitation frequency, total amount of heavy precipi- tation and the proportion of it increase significantly. Secondly, in Xinjiang, the increasing trends of all extreme precipitation indices appear in high elevation （about 1 000 m a. s. 1. , or above） ; in east of the arid regions of Northwest China, spatial distributions of changing trends of the extreme precipitation indices present obvious seasonal differences： most of the regions are dominated by increasing trend in summer and autumn, but by decrea- sing trend in winter and spring.

关 键 词：西北干旱区 极端降水指数 时空分析 

分 类 号：P467[天文地球—大气科学及气象学]