Numerical study of fog deposition on vegetation for atmosphere-land interactions in semi-arid and arid regions
Numerical study of fog deposition on vegetation for atmosphere-land interactions in semi-arid and arid regions
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DOI：
10.1016/j.agrformet.2009.11.016
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发表时间：
2010-03
影响因子：
6.2
通讯作者：
G. Katata;H. Nagai;M. Kajino;H. Ueda;Y. Hozumi
中科院分区：
文献类型：
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作者：
G. Katata;H. Nagai;M. Kajino;H. Ueda;Y. Hozumi
本研究的目的是评估雾(云水)对植被的沉积及其对半干旱和干旱地区水和能量平衡的贡献。使用详细的陆地表面模式(SOLVEG)估计了沙特阿拉伯半干旱环境中林地上的雾沉积，该模式包括使用三维中尺度气象模式(MM5)模拟的气象条件下植被上的雾沉积。事实证明，MM5能够再现气象变量，并成功探测到雾事件，尽管它确实高估了雾中的液态水含量。尽管这种高估的误差幅度较小，但SOLVEG的计算表明，雾沉积为植物生长提供了比半干旱和干旱地区通常观察到的暴雨更有效的水源。叶表面的水分蒸发(叶表面水)通过减少蒸腾作用的需要来缓解植物的水分胁迫，即使由于雾沉积导致的叶表面水不滴落到土壤中，因此不是植物的水源。从叶表面水和土壤蒸发释放的潜热在白天降低了土壤和树叶的温度，进而缓解了林地的热应力。此外，在半干旱和干旱环境中遭受严重水分胁迫的植物，由于雾沉积导致叶表水蒸发量增加而导致的蒸腾速率降低，是用于光合作用的有效水源。我们的结果表明，在半干旱和干旱地区，雾沉积会影响发生在大气-陆地界面的水和热交换的准确性。
The aim of the present study was to evaluate fog (cloud water) deposition on vegetation and its contribution to the balance of water and energy in semi-arid and arid regions. Fog deposition onto the woodlands in semi-arid environments in Saudi Arabia was estimated using a detailed land surface model (SOLVEG) that included fog deposition on vegetation in meteorological conditions simulated using a three-dimensional mesoscale meteorological model (MM5). MM5 proved capable of reproducing meteorological variables and successfully detected fog events, although it did overestimate the liquid water content of the fog. Despite the margin of an error due to that overestimation, SOLVEG calculations indicated that fog deposition provides a more effective source of water for plant growth than the heavy rainfall typically observed in semi-arid and arid areas. Water evaporation from the surfaces of the leaves (leaf surface water) eases the plant’s water stress by reducing the need for transpiration, even if the leaf surface water due to fog deposition does not drip onto the soil and is thus not a source of water for the plants. Latent heat being released through evaporation from the leaf surface water and soil reduces the temperature of the soil and leaves during the daytime, which in turn then eases heat stress in woodlands. Moreover, the decreased transpiration rates that result from the increase in evaporation from the leaf surface water due to fog deposition is an effective source of water for use in photosynthesis for the plants suffering from severe water stress in semi-arid and arid environments. Our results suggest that fog deposition can affect the accuracy of the water and heat exchange that take place in the atmosphere–land interface in semi-arid and arid regions.