Responses of reference crop evapotranspiration in Loess Plateau of Northwest China to climate change in 1961-2010 and estimation of future trend
It is essential to accurately estimate the reference crop evapotranspiration (ET0) in semiarid areas where the water resources are limited and excessively explored, which would be greatly helpful for planning the irrigation water supply and understanding the effects of climate change on hydrological processes. Based on the 1961 -2010 daily meteorological data from 67 meteorological stations in the Loess Plateau of Northwest China, and by using Penmen-Monteith equation, the reference crop evapotranspiration (ET0) in the Plateau was calculated, and, in combining with the many years' variations of various meteorological factors, the causes of the past years ET0 change in the Plateau were analyzed. On these bases, the future trend of the ET0 was estimated by the rescaled range analysis method. In the study area, the sensitivity of ET0 to mean air temperature was relatively low. However, due to its great variation, the mean air temperature was the dominant factor inducing the ET0 change, with a contribution rate of 6. 37%. Solar radiation and wind speed also had greater contribution rate to the ET0 change. Actual vapor pressure, due to its smaller variation, had minor effects on the ET0, only with a contribution rate of 1.36%. Spatially, air temperature had positive contribution to the ET0 change, wind speed and solar radiation had negative contribution in most regions, whereas actual vapor pressure had positive contribution in northern part and but negative contribution in southern part. Within a definite period in the future, the ET0 would keep the same change trend as the past. This study provided a basis for developing appropriate measures to reduce the losses from drought in the Loess Plateau.
国家科技期刊平台
NSTL
万方数据
维普
