泾河上游典型站近45年参考作物蒸散量变化特征

Variation characteristics of reference crop evapotranspiration of typical stations in upper basin of the Jinghe River in recent 45 years

为了更好地探讨泾河上游地区植被耗水的变化情况,利用泾河上游4个典型站点近45 a的逐日气象资料,采用Penman-Monteith公式,计算了日参考作物蒸散量,并对ET0的日、月、年值的变化特征进行了分析,同时分析了影响ET0的主要气候因子。结果表明:泾河上游ET0的日均值和月均值与大气温度、日照时数等气象要素均达到极显著相关,与风速的相关程度最低,ET0日变化和月变化均呈现为相似的单峰型变化趋势,峰值出现在夏季7月份。近45年来,只有隆德ET0年值呈显著性增加,其他站ET0年值变化不明显。固原的夏季,隆德的冬、夏、秋季的ET0呈显著性变化,其他站各季节变化均不明显。

To study variation characteristics of vegetation evapotranspiration in the upper basin of Jinghe river, using the meteorological data collected from 4 typical stations in recent 45 years in the upper basin of Jinghe river, the reference crop evapotranspiration （ETo） of each station was calculated with Penman-Monteith equation. The variation characteristics of daily, monthly and annual ETo were analysed, and the main meteorological factors which influced ETo were anlysed. The results show that there is a very significant correlation between the daily, monthly ETo and temperature, sunshine hours and vapor pressure, and the correlation between ETo and wind speed is relatively smaller. Both daily and montly average ETo curves have single peak, and the peak appears in July. In recent 45 years, there is a significant increasing trend of annual ETo in Longde, while there are no significant changes in other stations. There is a significant change trend of ETo in Guyuan in summer and in Longde in winter, summer and autumn, while therer are no significant change in each season of other stations.