博州不同级别降水及极端降水事件的时空变化  

Spatial-temporal Variation of Precipitation for Different Grade and the Events of Extreme Precipitation over Bole,Xinjiang

作　　者：辛渝 崔彩霞[2] 张广兴[2] 张新 刘兴旺 盛晓琼[4] 

机构地区：[1]新疆自治区气候中心,新疆乌鲁木齐830002 [2]中国气象局乌鲁木齐沙漠气象研究所,新疆乌鲁木齐830002 [3]新疆博州气象局,新疆博乐833400 [4]新疆气象信息中心,新疆乌鲁木齐830002

出　　处：《中国沙漠》2008年第2期362-369,共8页Journal of Desert Research

基　　金：“新疆太阳能资源评估业务系统建设”资助;“中国气象局气候变化专项(CCSF2007-30)”共同资助

摘　　要：根据1961—2005年新疆博州(博尔塔拉蒙古自治州的简称,下同)4站逐日降水资料,用阈值检测方法计算出博州地区极端降雨(雪)的阈值,并用气候趋势系数、Kendall-τ秩次相关以及滑动t检验等分析了博州地区不同量级降水日数以及极端降水日数的变化特征。研究表明,博州地区极端降水阈值与年平均降水量的空间分布基本一致:山区大,盆地小,地区间差异极大。3—10月一日降水量≤0.2mm的微量降雨日数大范围减少;年降水量增加的方式在不同子区域是不同的:①对于年平均降水量仅有100mm左右的艾比湖一带而言,主要体现在中雨、小雪次数的增加上,其他量级的雨雪日数及强度增加趋势不显著,这种增量对干旱区而言很小,无法改变干旱区的本质。②博河上游地区夏半年主要体现在小雨、大雨次数的增加以及中雨强度的增加上,冬半年主要体现在小雪、大雪或极端降雪日数的增加以及大雪、暴雪强度的增加上。虽然博河上游地区大雨次数显著增加,但强度显著降低。这种增加方式导致博河上游地区冬季牧区易出现雪灾,夏季易出现洪灾。③博河中游地区主要体现在小雪、中雪、大雪(或极端降雪)、中雨频次以及小雨强度的增加上,而且一日降水量≤0.2mm的微量降雨日数的减少趋势大于其他量级降雨总次数的增加趋势。降水日的这种变化方式在该区域气候显著偏暖的气候背景中,极易造成春夏阶段性极端干旱事件频发。Based on the data of day-by-day precipitation during 1961-2005 from four meteorological stations over Bole region（called Bortala Mongolia Autonomous Prefecture for short）,Xinjiang,the thresholds of extreme snow and rain are measured by the method of threshold detection as well as the variation features about the frequencies of precipitation for various grade and the events of extreme precipitation are analyzed by methods of the climatic tendency coefficient,the Kendall-τ rank and order correlation and the successive running t-test etc.The results show that the spatial distribution of extreme precipitation threshold is basically consistent with that of annual precipitation in Bole region,that is larger in the Mountains than that in the Basins,and with obvious regional differentiation.The precipitation days less than 0.2 mm·d-1 during March to October decreased strikingly in large area in these years;the increase of annual precipitation varied among regions.①For the Aibinur Lake watershed where the annual mean precipitation is about 100 mm,the increase of annual precipitation was mainly caused by the increase of frequencies of moderate rain and light snow,while the frequencies of wet days for the other grade,no matter snow or rain is,displayed an insignificant increasing tendency.Such small increase can＇t change the nature of arid region.②For the upper reaches of the Bole River,the annual precipitation was mainly due to the increase in frequencies of light rain,heavy rain and the increase in intensity of moderate rain in summer,and due to the increase in frequencies of slight snow,heavy snow or the extreme snow and the increase in intensity of heavy snow and torrential snow in winter.Such increase pattern easily brings about snow disasters in winter and floods in summer.③In the middle reaches of the Bole River,the increase of annual precipitation was mostly caused by the increase in frequencies of slight snow,moderate snow and the heavy snow（or extreme snowfall） and the increase in intensity of li

关 键 词：极端降水 降水频次 降水强度 年降水量 博州地区 

分 类 号：P426.6[天文地球—大气科学及气象学]