1961—2010年黄土高原地区参考作物蒸散量对气候变化的响应及未来趋势预估

Responses of reference crop evapotranspiration in Loess Plateau of Northwest China to climate change in 1961-2010 and estimation of future trend

根据1961—2010年我国黄土高原地区67个气象站常规气象资料,基于Penman-Monteith公式计算了参考作物蒸散(ET0),并结合各气象因子的多年变化探讨了ET0变化的原因,在此基础上,应用基于分型理论的R/S方法对黄土高原区ET0未来的变化趋势进行了预测。结果表明:平均气温的敏感性虽较低,但因其显著变化,成为引起ET0变化的主导因子,贡献达到6.37%,太阳辐射和风速次之,实际水汽压敏感性较大,但因变化小,贡献仅为1.36%;空间分布上,气温对ET0的变化均为正贡献,风速和太阳辐射多为负贡献,实际水汽压在北部为负贡献,南部多为正贡献;未来一段时间ET0仍然保持与过去相一致的变化趋势。

It is essential to accurately estimate the reference crop evapotranspiration （ETo ） 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 ev＇apotranspiration （ETo ） in the Plateau was calculated, and, in combining with the many years＇ variations of various meteorological factors, the causes of the past years ETo change in the Plateau were analyzed. On these bases, the future trend of the ETo was estimated by the rescaled range analysis method. In the study area, the sensitivity of ETo to mean air temperature was relatively low. However, due to its great variation, the mean air tem- perature was the dominant factor inducing the ETo change, with a contribution rate of 6.37%. Solar radiation and wind speed also had greater contribution rate to the ETo change. Actual vapor pressure, due to its smaller variation, had minor effects on the ETo , only with a contribution rate of 1.36%. Spatially, air temperature had positive contribution to the ETo 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 def- inite period in the future, the ETo would keep the same change trend as the past. This study pro- vided a basis for developing appropriate measures Plateau. to reduce the losses from drought in the Loess