黄土高原地区近50年参考作物蒸散量变化特征

Analysis of effects of climate change on reference evapotranspiration on the Loess Plateau in recent 50 years

为了探求黄土高原地区深层土壤干燥化过程及成因和该地区植被耗水的变化情况,该文根据黄土高原5站点近50a的日气象资料,利用Penman-Monteith公式计算了日参考作物蒸散量,并分析了ET0的日均值、月均值和年值的变化特征,同时分析了平均温度、最高温度、最低温度、日照时数、风速和相对湿度与ET0的相关性。结果表明:黄土高原地区ET0日值和月均值与大气温度、日照时数均达到了极显著的相关性,其ET0日值和ET0月均值曲线均呈单峰型,存在明显的季节变化特征,峰值均出现在6月。除了西安和西宁ET0年值显著降低外,其他3站点的年际间变化趋势不显著,同时除西宁站外其他各站点在20世纪80年代后ET0均有上升的趋势。

To study the reason of soil desiccation and variation characteristics of vegetation evapotranspiration in the loess plateau. Based on the meteorological data collected from five meteorological stations in recent 50 years in the loess plateau, the reference crop evapotranspiration （ET0） was calculated with the Penman-Monteith equation. The change characteristics of daily, monthly and annual ET0 were analyzed respectively. The correlation of average temperature, maximum temperature, minimum temperature, sunshine hours, wind speed and average relative humidity with ET0 were analyzed. The results show that there is a very significant correlation between the daily, monthly ET0 and temperature and sunshine hours, respectively. Both highest daily and monthly average ET0 appeare in June, respectively. Both daily and monthly average ET0 curves have sigle peak, respectively, the and distribution of daily and monthly ET0 are consistent with the variation of season changes. Apart from the significant decreasing trend of annual ET0 in Xi’an and Xining, there were no significant changes in Yan’an, Yuling and Lanzhou, meanwhile, the ET0 show increasing trend since 1980s except Xining.