甘肃黄土高原地表湿润状况时空变化特征  

Characteristics of temporal and spatial distribution of surface humid conditions over Loess Plateau of Gansu

作　　者：蒲金涌[1,2] 姚小英[3] 马鹏里 王位泰 

机构地区：[1]中国气象局兰州干旱气象研究所,甘肃省干旱气候变化与减灾重点实验室,中国气象局干旱气候变化与减灾重点开放实验室,甘肃兰州730020 [2]甘肃省天水农业气象试验站,甘肃天水741020 [3]天水市气象局,甘肃天水741000 [4]兰州区域气候中心,甘肃兰州730020 [5]庆阳市气象局,甘肃庆阳745000

出　　处：《干旱区地理》2010年第4期588-592,共5页Arid Land Geography

基　　金：甘肃省气象局“十人计划”;国家科技部公益行业专项(GYHY200806021)资助

摘　　要：干湿状况的时空分布是干旱半干旱区的气候研究热点之一,现代气候变暖加速了黄土高原暖干化的进程。根据甘肃省黄土高原13个气象站1961-2006年气象资料,利用Thornthwait公式计算该地区潜在蒸散及湿润指数,并分析了潜在蒸散值与蒸发量的相关关系、潜在蒸散及湿润指数的时空分布特征。结果表明,潜在蒸散计算值与该地蒸发量的实测值相关性显著。在蒸发较盛的3～9月,两者之间的相关性可以通过0.01的信度检验。1961-2006年潜在蒸散随时间呈二阶函数变化,20世纪80年代中期以来潜在蒸散呈明显的线性上升趋势。1984年是变换的转折点,1984-2006年陇西黄土高原潜在蒸散以19.8 mm/10 a的速度上升,陇东黄土高原以31.1 mm/10 a的速度上升。一年之中,湿润指数的变化呈开口向上的抛物线。湿润指数最低的季节为夏季,最高的季节为秋季。20世纪60年代以来,甘肃黄土高原的湿润状况逐渐变差,秋季变化最显著,从20世纪60年代到21世纪初,陇西黄土高原湿润指数下降了0.45,陇东黄土高原湿润指数下降了0.35。湿润状况最差的地区为环县;沿陇海铁路线"兰州-定西-天水"一线是湿润状况较差的地区;湿润状况较好的地区分布在陇东黄土高原的南部及陇西黄土高原的西侧。The temporal and spatial distribution of dry and humid is one of hotspot of research in arid and semiarid regions. The modem climate warming made the condition of drying and warming more seriously in Loess Plateau in recent years. Based on the meteorological data of 13 weather stations which located on the Loess Plateau of Gansu from 1961 -2006, we calculated the potential evapotranspiration with Thomthwaite formula and humid index. The correlation between the potential evapotranspiration and evaporation, characteristics of temporal and spatial distribution of surface humid condition and of potential evapotranspiration over Gansu Loess Plateau were analyzed. The results showed that there was significant correlation between the value of potential evapotranspirtion and the value of evaporation which measured on the spots and the correlation coefficient between them is above 90% confidence level during March to September in a year. It also showed that the trend of potential evapotranspirattion turned to follow second order function with time during 1961 - 2006 and the value of potential evapotranspiration increased significantly after middle of 1980＇s. The turning point of the potential evapotranspiration variation was in 1984 and the potential evapotranspiration was increasing with the speed of 19.8 mm every ten years in the western part of Gansu Loess Plateau and was increasing with the speed of 31.1 mm every ten years in the eastem part of Gansu Loess Plateau after 1984. It indicated that the annual variation of humid index followed the parabola which opening portion turned upwards, in which the period of lowest humid index is in summer and the period of highest humid index in autumn. It also indicated that the humid index was becoming low after 1960g and the period of significant variation was in autumn. It showed that the humid index had decreased by O. 45 in the western part of Gansu Loess Plateau and had decreased by 0.35 in the eastern part of Gansu Loess Plateau in autumn after 1960s. The lowest humid ind

关 键 词：黄土高原 甘肃 地表 湿润指数 变化 

分 类 号：P426.13[天文地球—大气科学及气象学]