黄土高原陆地表层最大可能蒸散量的变化特征

基于黄土高原1961—2008年月平均气温、最高气温、最低气温、相对湿度、降水量、风速和日照百分率等气候要素资料,应用修订的Penman-Monteith（P-M）模型计算了最大可能蒸散量,分析其时空分布、异常分布特征和次区域时间演变特征。结果表明：1961—2008年间,黄土高原最大可能蒸散量多年平均在400~800 mm之间,大部分区域650~750 mm之间。一致性异常分布是黄土高原最大可能蒸散量的最主要空间模态。黄土高原最大可能蒸散量的异常空间分布可分为以下3个关键区：高原西北部区、高原东北部区和高原东南部区。高原西北部区域最大可能蒸散量呈显著增加趋势,且发生了突变现象;高原东北部区域最大可能蒸散量呈显著下降的趋势,也发生了突变;而高原东南部区域下降趋势不显著,未发生突变。黄土高原最大可能蒸散量的3个空间分区中,3 a的周期振荡表现得比较显著。

Change of terrestrial surface potential evapotranspiration in Loess Plateau

On the basis of climatic observational data of monthly average temperature,maximum temperature,minimum temperature,relative humidity,precipitation,wind speed and sunshine duration in Loess plateau from 1961 to 2008,the potential evapotranspiration was computed by using revised Penman-Monteith Model.The temporal-spatial distribution,anomaly distribution and sub-regional temporal variations of the potential evapotranspiration were analyzed as well.The results show that the annual average potential evapotranspiration was mainly between the value of 400~800 mm,and in most parts of the study regions it was 650~750 mm.The main spatial model of annual potential evapotranspiration on Loess plateau is consistent anomaly distribution.The spatial model on Loess plateau can be divided into three key areas： the northwest,the northeast and the southeast areas of Loess plateau,respectively.The potential evapotranspiration displayed a significantly ascending trend and appeared an abrupt change in the northwest area;and in northeast area it displayed a descending trend and appeared an abrupt change too;in the southeast areas of Loess plateau,the potential evapotranspiration displayed a descending trend,but no abrupt change appears.There is an obviously fluctuating period of 3 years on Loess plateau from the year 1961 to 2008.