雅鲁藏布江流域潜在蒸散发的气候敏感性及其变化的主导因子分析

Analysis on the Sensitivity and Dominant Meteorological Factors Identification of Potential Evapotranspiration Variation in Yarlung Zangbo River Basin

潜在蒸散发敏感性分析是研究水资源对气候变化响应的基础内容之一。基于气象站点的观测资料,应用Penman-Monteith公式计算雅鲁藏布江流域1961—2012年逐日的潜在蒸散发,并分析其时空分布特征;在此基础上,分析潜在蒸散发对4个气象因子(平均气温、风速、太阳辐射、相对湿度)的敏感程度及各气象因子的贡献率,识别出雅鲁藏布江流域潜在蒸散发的敏感因子和主导因子。结果表明:(1)1961—2012年,雅鲁藏布江流域的潜在蒸散发呈现显著增加趋势,增幅为8.81 mm/10 a;年潜在蒸散发空间分布表现为中游河谷地区高于其他地区;(2)对于雅鲁藏布江流域大部分区域,潜在蒸散发量对气候因子的敏感性排序为:太阳辐射>平均气温>相对湿度>风速,各气象因子的贡献率从高到低为:平均气温>风速>相对湿度>太阳辐射。总体而言,雅鲁藏布江流域潜在蒸散发对太阳辐射最为敏感,而平均气温是1961—2012年间潜在蒸散发变化的主导因子。

Analysis on the sensitivity of potential evapotranspiration is one of the basic research topics of water cycle respons to climate change.Based on the ground meteorological data in the Yarlung Zangbo River Basin,we calculated the daily potential evapotranspiration from 1961 to 2012 by using the Penman-Monteith formula,and analyzed its temporal and spatial distribution characteristics.On these bases,the sensitivity of potential evapotranspiration to four meteorological factors(average temperature,wind speed,solar radiation,and relative humidity)and the contribution rate of each meteorological factor to the variation of potential evapotranspiration were also calculated,and then the more sensitive factor and the dominant factor were identified.The results showed that:(1)from 1961 to 2012,the potential evapotranspiration in the Yarlung Zangbo River Basin presented the significantly increasing trend with an increase of 8.81 mm/decade;the annual potential evapotranspiration had obvious spatial distribution characteristics that was higher in mid-stream valley than in other regions;(2)with respect to most regions of the Yarlung Zangbo River Basin,the potential evapotranspiration was more sensitive to solar radiation,and followed by average temperature,relative humidity,wind speed;and the contribution rate of each meteorological factor decreased in the order:average temperature>wind speed>relative humidity>solar radiation.In general,the average temperature was the leading factor responsible for the change of the potential evapotranspiration in the Yarlung Zangbo River Basin between 1961 and 2012.