为实现大区域尺度参考作物蒸散量(reference crop evapotranspiration,ET0)资料缺失情况下的准确计算,该文将长江流域划分为上、中、下游3个子区域,基于反距离权重法的新型空间展布方法得到3个虚拟站点分别代表每个子区域,利用长江流域102个站点1964-2013年近50a的逐日气象数据,根据FAO-56 Penman Monteith(P M)法、Hargreaves Samani(H S)法、Irmark Allen(I A)法、Priestley Taylor(P T)法、Makkink(M K)法、Penman Van Bavel(PVB)法、1948年 Penman(48-PM)法分别计算每个站点逐日ET0,并以P M法为标准,利用Nash Sutcliffe系数(CD)、逐日相对均方根误差(RMSE)、Kendall一致性系数(K)对其适用性进行评价,结果表明:在3个子区域6种ET0计算方法的日值与P M法拟合方程确定系数R2均通过了极显著水平检验(α=0.01),长江上游P T法ET0日值计算精度最高(ET0日值拟合方程斜率为1.030,RMSE=0.341 mm/d,CD=0.886,K=0.829),H S法、I A计算精度较低(ET0日值拟合方程斜率分别为1.427、1.308,RMSE=0.909、0.829 mm/d,CD=0.581、0.523,K=0.792、0.742),长江中、下游PVB法计算精度最高,P T法计算精度次之,H S法与I A法计算精度较低；长江上游6种算法ET0月值的计算精度由高到低依次为P T法、PVB法、M K法、48 PM法、H S法、I A法,与P M法的平均误差分别为0.27、0.35、0.51、0.48、0.74、0.78 mm/d；长江中、下游6种算法计算精度由高到低为PVB法、P T法、M K法、48 PM法、H S法、I A法；整个长江流域P T法、PVB法与P M法ET0计算结果相对误差均在35%以下,H S法、I A法计算精度较低,其相对误差基本高于40%；因此,PVB法与P T法在整个长江流域的计算精度较高,可作为长江流域ET0简化计算推荐方法。

In order to making true the exact calculation of reference crop evapotranspiration(ET0) and increase the accuracy with the lack of meteorological data in the large area, the Yangtze River Basin is divided into upstream, midstream and downstream according to the altitude of the stations.A new method of space distribution based on Inverse Distance Weighted Interpolation method is raised which can present every substream, including upstream, midstream and downstream.This method can include the connection of different stations.There are 102 meteorological stations which can provide 50 years of daily meteorological data from 1963 to 2013.In this research, we used the methods of Penman Monteith(P M), Hargreaves Samani(H S), Irmark ALLEN(I A), Pristley Taylor(P T), Makkink(M K), Penman Van Bavel(PVB), 1948 Penman(48 PM) to calculate daily ET0 of every stations of the Yangtze River Basin.The method of Penman Monteith can be used to be the standard method to calculate standard daily ET0 to evaluate other methods because of its accuracy.The coefficient of Nash Sutcliffe, the daily relative root mean square error, the consistency coefficient of Kendall can be used to evaluate the precision index of the method.The result showed that the best method of daily ET0 imitative effect compared with P M is PVB in the three substreams, because the slope of the imitative equation of PVB in upstream is 0.946, the slope in midstream is 1.065, and the slope in downstream is 1.005.The method of Pristley Taylor has a better effect in the midstream and downstream, and the slopes of the imitative equation are 1.030 and 1.201.The method of Makkink also has a good effect in the midstream and downstream, and the slopes are 0.857 and 0.936.The determination coefficient of daily ET0 imitative equation of these six methods all achieved very significant levels(α=0.01) in three substreams.The methods of Pristley Taylor and Penman Van Bavel have high calculation accuracy in all area of the Yangtze River Basin, and the highest absolute error of monthly ET0 is 0.55 mm/d using the method of Pristley Taylor, at the same time the highest absolute error of monthly ET0 is 0.48 mm/d using the method of Penman Van Bavel.The effect of the methods of Hargreaves Samani and Irmark ALLEN are worse than other methods to calculate monthly ET0 in the whole Yangtze River Basin.The method of Pristley Taylor is the best method to calculate ET0 in the upstream of the Yangtze River Basin, because the daily relative root mean square error is 0.341 mm/d, the coefficient of Nash Sutcliffe is 0.886, and the consistency coefficient of Kendall is 0.829.The method of Penman Van Bavel is the best method to calculate ET0 in the midstream and downstream of the Yangtze River Basin.In the midstream, the daily relative root mean square error is 0.201 mm/d, the coefficient of Nash Sutcliffe is 0.973, and the coefficient of Nash Sutcliffe is 0.926.In the downstream, the daily relative root mean square error is 0.306 mm/d, the coefficient of Nash Sutcliffe is 0.954, and the consistency coefficient of Kendall is 0.869.In the Yangtze River Basin, the relative error of Pristley Taylor and Penman Van Bavel are the lowest among these methods which are less than 35%, the relative error of is the highest among these methods which is more than 40%.In conclusion, the method of Pristley Taylor and Penman Van Bavel are the best methods to calculate ET0 in the Yangtze River Basin, the calculation process are simple at the same time.The method of Pristley Taylor and Penman Van Bavel can be a simplified recommendation of calculating ET0 in the Yangtze River Basin.

S161.4

国家科技支撑计划项目(2015BAD24B01)；农业部旱作节水农业重点实验室基金(HZJSNY201502)；国家自然科学基金项目(51009101)；南方丘区节水农业研究四川省重点实验室开放基金项目(JSSYS2014-C)；四川省软科学研究计划项目(2015ZR0157)