泾河上游典型站近45年参考作物蒸散量变化特征

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ETo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.

Variation characteristics of reference crop evapotranspiiration of typical stations in upper basin of the jinghe River in recent 45 years

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 refer-ence crop evapotranspiration(ET₀)of each station was calculated with Penman-Monteith equation. The variation charac-teristics of daily, monthly and annual ET₀were analysed, and he main meteorological factors which influced ET₀ were anlysed. The results show that there is a very significant correlation between the daily, monthly ET₀and temperature, sunshine hours and vapor pressure, and the correlation between ET₀ and wind speed is relatively smaller. Both daily and montly average ET₀ curves have single peak, and the peak appears in July. In reccnt 45 years, there is a significant in-creasing trend of annual ET₀ in Longde, while there are no signifieant changes in other stations. There is a significant change trend of ET₀ in Guyuan in summer and in Longde in winter, summer and autumn, while therer are no significant change in each season of other stations.