三温模型是近年提出的测算蒸散量和评价环境质量的一种方法，因为该模型的核心是表面温度、参考表面温度、气温，所以被称为“三温模型”。该文通过理论分析结合实验的方法， 讨论了用三温模型测算土壤蒸发量的方法及其验证。通过引入没有蒸发的参考土壤的概念，三温模型中用下式计算土壤蒸发量：LE=Rn-G-(Rnd-Gd)(Ts-Ta)/Tsd-Ta 式中，E为土壤蒸发量，L为水汽的汽化潜热，Rn和Rnd为蒸发土壤面和参考土壤面的净辐射，G和Gd为蒸发土壤和参考土壤热通量，Ts、Tsd、Ta分别为蒸发土壤的表面温度、参考土壤表面温度、气温。试验结果表明，在参考土壤和蒸发土壤中，能量通量存在明显差异，参考土壤中的土壤热通量和净辐射通量均小于蒸发土壤，而显热通量则大于蒸发土壤；在一般情况下，参考土壤的表面温度最高，蒸发土壤表面温度次之，大气温度最低，在土壤湿润时，这些差异更为显著。 经过与大型称重式蒸渗仪的实测值比较，三温模型能较好地计算土壤蒸发量，在22 d的实验期间内，绝对平均误差仅为0.17 mm•d-1，相关系数达r2=0.88。与热电偶测温结果相比较，采用红外温度计测温的结果更为精确，和实测值的绝对平均误差仅为每天0.15 mm•d -1，相关系数达r2=0.94，表明三温模型有较好的精度。另外，三温模型在计算土壤蒸发量时，所需要的参数种类少（净辐射、土壤热通量、温度），不含经验系数，不需要空气动力学阻抗和表面阻抗等参数，因此简便实用，具有较好的应用前景。
The “Three temperatures (3T) model” is a recently proposed method to estimate evapotranspiration and evaluate environmental quality. Because the key components for this model are three temperature variables, it is referred to as the “3T model”. This study discusses the procedures used to estimate evaporation , and model is verified based on a theoretical analysis and experimental data. By introducing a reference dry soil (a soil without evaporation), soil evaporation (E) can be calculated by:LE=Rn-G-(Rnd-Gd)(Ts-Ta/Tsd-Ta where L is latent heat of vaporization, Rn and Rnd are the net radiations of drying and dry soil, respectively. G and Gd are soil heat fluxes in drying soil and dry soil, respectively. Ts and Tsd are the surface temperatures of drying soil and dry soil, respectively. Ta is the air temperature. Results of the experimental work indicated that the energy fluxes over drying and dry soil were significantly different. Soil heat flux and net radiation on the dry soil are smaller than that on the drying soil, whereas the heat flux of the dry soil is higher than that of the drying soil. Typically, the dry soil surface temperature was higher than that of the drying soil surface temperature and the drying soil surface temperature was higher than the air temperature. Results of a field experiment showed that the measured E (using of a weighing lysimeter) and the calculated E using the 3T model agreed with each other and the mean absolute error (MAE) between them was 0.17 mm•d-1 with a regression coefficient of r2=0.88. Furthermore, by using the temperature measured by infrared thermometers , the MAE between measured and estimated evaporation was 0.15 mm•d -1 with a regression coefficient of r2=0.94. These results showed that evaporation as estimate d by 3T model is accurate. The main advantage of the 3T model is that only a few parameters (temperature, net radiation and soil heat flux) are required. Soil surface resistance, aerodynamic resistance, and other empirical parameters are no t necessary.