Measurement of Evaporation from Bare Soil and its Estimation Using Surface Resistance
Measurement of Evaporation from Bare Soil and its Estimation Using Surface Resistance
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DOI：
10.1029/96wr00268
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发表时间：
1996-05
影响因子：
5.4
通讯作者：
C. Daamen;L. Simmonds
中科院分区：
文献类型：
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作者：
C. Daamen;L. Simmonds
土壤蒸发，Es，是重要的陆地表面能量平衡，并已估计在许多研究中使用的表面阻力的方法。我们调查这种方法的准确性，使用详细的测量和模拟。每小时的蒸发速率测定微蒸仪和称重传感器在两个半干旱的网站与裸露的土壤。土壤剖面中的水（液体和蒸汽）和热通量的数值模型（土壤水分，能量和蒸腾（SWEAT）模型）提供了一个精确的模拟测量蒸发率。利用SWEAT的输出，确定了土壤阻力rs与土壤表面含水量θs（0-20和0-50 mm）之间的关系，并据此估算了Es。这些基于rs的模型在几天的时间内表现良好，但每小时甚至每天的Es估计都很差。在白天早期的时间测量的Es率和潜在的蒸发率之间的特性分歧没有很好地模拟RS为基础的模型。Anrs（θs）函数对不同位置的相似土壤低估了Es约60%。我们的工作表明，由蒸发需求和近地表土壤含水量θs计算的rs可能更准确。
Evaporation from soil, Es, is important to land surface energy balance and has been estimated in many studies using a surface resistance approach. We investigate the accuracy of this approach using detailed measurement and simulation. Hourly evaporation rates were measured using microlysimeters and load cells at two semiarid sites with bare soil. A numerical model of water (liquid and vapor) and heat fluxes in a soil profile (the soil water, energy, and transpiration (SWEAT) model) provided an accurate simulation of measured evaporation rates. Using output from SWEAT, relationships between soil resistance rs and soil surface water content θs (0–20 and 0–50 mm) are determined and are then used to estimate Es. These rs-based models performed well over a period of several days but provided poor estimates of Es on an hourly or even a daily basis. A characteristic divergence between measured Es rates and potential evaporation rates at a time during the early daylight hours was not well simulated by rs-based models. Anrs(θs) function for a similar soil at a different location underestimated Es by about 60%, Our work suggests that rs calculated from both evaporative demand and near-surface soil water content θs is likely to be more accurate.