Estimation of Hourly Evapotranspiration in Arid Regions by a Simple Parameterization of Canopy Resistance
Estimation of Hourly Evapotranspiration in Arid Regions by a Simple Parameterization of Canopy Resistance
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DOI：
10.14877/agrmet2.isam08.0.94.0
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发表时间：
2009
影响因子：
1.3
通讯作者：
B. He;H. Oue;T. Oki
中科院分区：
文献类型：
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作者：
B. He;H. Oue;T. Oki
用于估算蒸散量（ET）的彭曼-蒙特斯（PM）方程已在国际上得到应用。其弱点是冠层阻力的估计。本文提出了一种简单的冠层阻力模型，用于估算每小时的蒸散量。提出了冠层阻力、气动阻力和气候阻力之间的非线性函数关系。为了验证模型，我们在河套灌区的一片灌溉麦田中收集了数据，该灌区是黄河沿岸最大的灌区。在小麦生长周期中测量了地表能量平衡和近地表天气变量。通过鲍文比能量平衡法获得每小时测量的ET值。预测与测量的 ET 数据的回归导致 r2=0.97，斜率为 0.98，截距为 0.01，在 99% 置信度下与 1 和 0 没有区别。这项研究提供了一种利用通用气象数据库来估计蒸散发的简单方法，该数据库可以进一步应用于考虑可变冠层阻力影响的水文模型。
The Penman-Monteith (PM) equation for evapotranspiration (ET) estimation has been applied in the world. Its weak point is the estimation of the canopy resistance. This paper proposed a simple canopy resistance model for estimating ET on an hourly basis. A non-linear functional relationship between canopy resistance, aerodynamic resistance, and climatic resistance was proposed. For model validation, data was collected in an irrigated wheat field in the Hetao Irrigation District, which is the largest one along the Yellow River. Surface energy balance and near-surface weather variables were measured during the growth cycle of wheat. Measured hourly ET values were obtained by the Bowen ratio energy balance method. Regression of predicted versus measured ET data resulted in r2=0.97 with slope of 0.98 and intercept of 0.01 which are not different from 1 and 0 at 99% confidence. This study provided a simple way to estimate ET with a general available meteorological database which can be further applied in hydrologic models considering effects of variable canopy resistance.