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模拟蒸散的物理过程,计算农田蒸散量是进行生态系统水资源评价和管理的重要手段,同时也是气象部门进行土壤湿度预报的首要条件。本研究以玉米农田为研究对象,基于涡度相关法观测的蒸散实测资料,比较分析了基于常规气象数据的蒸散模型(Hargreaves法、Priestley-Taylor法、FAO-Penman-Monteith法)和基于气象梯度数据的蒸散模型(波文比法、梯度法、生态系统过程模型模拟)的模拟精度。结果表明:①Hargreaves法、Priestley-Taylor法和FAO-Penman-Monteith法日蒸散的模拟结果较为一致,总体上高估20%~26%,其中Priestley-Taylor法模拟结果最优;②生态系统过程模型模拟的农田日蒸散精度较高,但模型中涉及的物理过程和参数较多,在实际应用中难于获取;③波文比法在波文比小于0.4且仪器精度较高时可以得到较准确的估算值。研究同时还指出,仪器的安装高度及高差设计对梯度法估算蒸散十分重要。
To simulate the physical process of evapotranspiration and calculate the evapotranspiration of farmland is an important measure to evaluate and manage the water resources in the ecosystem. It is also the primary condition for the meteorological department to forecast the soil moisture. Based on the field data of evapotranspiration observed by eddy covariance method, the evapotranspiration model based on conventional meteorological data (Hargreaves method, Priestley-Taylor method and FAO-Penman-Monteith method) Simulation accuracy of data evapotranspiration model (wave ratio method, gradient method, ecosystem process model simulation). The results show that: ①Hargreaves method, Priestley-Taylor method and FAO-Penman-Monteith method are more consistent with the daily evapotranspiration results, which are overestimated by 20% -26%, of which Priestley-Taylor method is the best; ②Ecosystem Process Model Simulated field day evapotranspiration accuracy is high, but the physical processes and parameters involved in the model more difficult to obtain in practice; ③ Bowen ratio method in the wave ratio is less than 0.4 and the accuracy of the instrument can be more accurate estimated value. The study also pointed out that the installation of the instrument height and height of the gradient method is very important to estimate evapotranspiration.