甘肃中东部半干旱区参考作物蒸散量多种计算方法的比较研究

A comparative study on calculation methods of reference crop evapotranspiration in the semi-arid region of Central Eastern Gansu

为明确甘肃中东部丘陵沟壑地区参考作物蒸散量(ET0)在气象资料短缺条件下的计算方法,依据6个气象站的长系列资料,以FAO Penman-Monteith方法为标准,对7种ET0计算方法进行评价。结果表明:Hargreaves与FAO Penman-Monteith吻合最好,其次为Jensen-Haise,各地区年均标准偏差(RMBE)分别为120.0 mm、446.1 mm。Pennman、FAO-17 Penman、FAO-24 Radiation、Preiestley-Taylor计算结果偏高,各地区年均RMBE在3 122.1～1 383.4mm间,以FAO-24 Radiation差异最大。8种方程计算的年内月均ET0趋势基本呈单峰曲线,峰值出现在7月份。Hargreaves、Jensen-Haise两种方程3-9月差异大于1-2月和10-12月份; Penman、FAO-17 Penman、FAO-24Radiation、Preiestley-Taylor、Makkink 5种方程7月份差异最大,地区间表现不一。不同的方程与FAO PenmanMonteith方程均存在显著的线性相关关系(0. 994**≤R≤0.8743**),回归系数t检测均达到显著水平,以FAO Penman-Monteith方程为基础对各方程进行矫正是可行的。

In order to obtain simplified method to calculate evapotranspiration(ET0) of reference crop when meteorological data in hilly and gully regions of central east Gansu Province is lacking. Based on long series data from 6 meteorological stations,seven methods for ET0 calculation were evaluated using the FAO Penman-Monteith as the reference method. The results showed that the best match with FAO Penman-Monteith was Hargreaves,followed by Jensen-Haise with average annual standard deviations(RMBE) of 120.0 mm and 446.1 mm,respectively. The calculated results by using Penman,FAO-17 Penman,FAO-24 Radiation,and Preiestley-Taylor were higher than that of other two methods above,and the average annual RMBE was in the range of 3 122.1 ~ 1 383.4 mm,but the results from FAO-24 Radiation differentiated the most from that of FAO Penman-Monteith. The average monthly ET0 data of all eight models showed bell shaped curves with a peak in the month of July. The difference of Hargreaves and Jensen-Haise models from the reference method in Mar. to Sept. were greater than that in Jan. to Feb. and in Oct. to Dec.Pennman,FAO-17 Penman,FAO-24 Radiation,Preiestley-Taylor,and Makkink had the greatest difference appeared in July and they were various among regions. There were significant linear correlations between the data from all the models and that from the FAO Penman-Monteith model with the regression coefficients in the range of0.994**~ 0.874 3**. Therefore,it is feasible to correct the other equations using FAO Penman-Monteith model.