三种通过常规气象变量估算实际蒸散量模型的适用性比较

为了分析比较3种通过常规气象变量估算实际蒸散量模型的适用性，采用无量纲化分析方法将基于互补相关理论的平流-干旱（简称AA模型）模型和Granger模型与Katerji和Perrier提出的通过气象变量确定表面阻力进而直接估算实际蒸散量的PenmanMonteith(PMKaterji)模型转化为类似的可比形式，即将实际蒸散量与Penman潜在蒸散量之比(蒸散比)表示为Penman潜在蒸散量中辐射项所占比例的函数。3种模型分别采用不同的函数形式，通过对函数特性的分析发现， AA模型适用于既不非常干燥和也不非常湿润的环境，计算的实际蒸散量在干燥的环境下偏小，而在湿润的环境下偏大；Granger模型在蒸散比变化范围较大都适用，并且在一般湿润状况下与AA模型近似等价；PMKaterji模型在蒸散比变化范围较大时模拟效果不好。通过干旱(黑河试验沙漠与戈壁站)与湿润(淮河试验安徽寿县站)两种状况下的实测数据的对比分析验证了理论分析的正确性。

Evaluation of applicability of three evapotranspiration models using meteorological data

The applicability of three models used to estimate the evapotranspiration based on general meteorological data is analyzed. The models include the advection aridity (AA) model, Granger model and the improved Penman Monteith model proposed by Katerji and Perrier, namely PM Katerji model. The dimensionless analysis method is applied, by which the ratio of actual evapotranspiration to Penman potential evapotranspiration is expressed as a function of the proportion of the radiation term in Penman potential evapotranspiration. The three models use different functions, and the applicability of each model is analyzed according to the characteristics of the functions respectively. It is found that the AA model is applicable to the environment which is neither extreme dry nor extreme wet, it underestimates the actual evapotranspiration under dry conditions but overestimates under wet conditions. The Granger model is applicable to the conditions with a wide range of evapotranspiration ratio, and it is approximately equivalent to the AA model under ordinary wet condition. The simulation result of the PM Katerji model is not very good if the variation range of evapotrnaspiration is wide. The validity of the analysis result is verified by a case study.