摘要
用Penman公式计算了甘肃黄土高原20世纪60—90年代40 a来的潜在蒸散值,分析了潜在蒸散的时空变化特征并与蒸发皿所测值进行比较.结果表明:甘肃黄土高原潜在蒸散值的分布与纬度关系比较密切,随纬度的升高,潜在蒸散值增多,变化范围为1 600-2 200 mm.a-1;潜在蒸散值受气温、降水的支配比较大,80年代最小,其次为70、60年代,90年代最大.60—90年代各地潜在蒸散值比实测值高30%-40%,其中夏、秋季潜在蒸散均大于蒸发器所测值,以夏季相差最大,达40%-100%;冬季则小于蒸发器所测值.潜在蒸散量与蒸发器所测值虽在数值上有所差别,但趋势基本一致,蒸发器所测值的峰值变化落后于理论计算值0.5月.90年代以来,各地土壤水分亏缺值增多,植被生长季节,作物水分利用都未及最适宜状态.
The potential evapotranspirations for seven weather stations located on the Gansu Loess Plateau from 1961 to 2000 have been caculalted from Peman formula. A comparison between the potential evapotranspirations and the evapotranspirations observed by evaporation pan has been made. Then the characteristics of spatial and temporal variations have been analyzed. The result showed that the potential evapotranspiration increases close with latitude, with a changing range of 1 600-2 200 mm·a^-1. The potential evapotranspiration is mainly controlled by temperature and precipitation, with a minimum in the 1980s, maximum in the 1990s, a middle in the 1970s and 1960s. The potential evapotranspiration is higher than the observed one by 30% - 40% during 1961--2000. It also can be seen that the potential evapotranspiration is higher than the observed one in summer and autumn, reaching 40%-100% in summer. However, in winter it is lower than the observed one. The tendencies of potential and observed evapotranspirations are basically consistent, but the observed one has a delay of 0.5 month as compared with the potential one. Since the 1990s, the farmland soil moisture content has always in an unfavorable condition and the utilization of soil moisture has not attained a suitable condition during crop growth period in Gansu Loess Plateau.
出处
《冰川冻土》
CSCD
北大核心
2007年第1期126-130,共5页
Journal of Glaciology and Geocryology
基金
教育部重大项目"陇西黄土高原植被恢复与重建过程中水文生态大气动态耦合过程研究"
科技部科研院所社会公益研究项目(2004DIB5J192)
甘肃省科技攻关计划项目"甘肃干旱生态环境对全球气候变暖的响应及减灾技术的研究"(2GS042-A44-017)资助
关键词
甘肃黄土高原
土壤水
蒸散发
时空变化
Gansu Loess Plateau
soil water
evapotranspiration
spatial and temporal variation
