Model study on micrometeorological aspects of rainfall interception over an evergreen broad-leaved forest
Model study on micrometeorological aspects of rainfall interception over an evergreen broad-leaved forest
复制标题
常绿阔叶林截雨微气象因素模型研究
DOI：
10.1016/0168-1923(95)02301-1
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发表时间：
1996
影响因子：
6.2
通讯作者：
K. Mizutani
中科院分区：
文献类型：
--
作者：
Tsutomu Watanabe;K. Mizutani
利用一个40层的林冠模型，研究了万年青阔叶林降雨截留的微气象特征。在该模式中，在计算的冠层内的小气候下，以叶为基础计算截留水的蒸发和蒸腾，作为能量收支方程的解。辐射强度，风速，空气温度，和冠层内和上方的特定湿度的配置文件计算从辐射能量传输，大气扩散的动量，感热，和水蒸气，和大气湍流动能方程的组合方程。通过与室内试验和田间观测结果的比较，发现该模型可以很好地估计单叶片和整个冠层的截留水蒸发。在计算过程中，模拟了一个负的感热通量，表现出与观测基本一致，并提供了能量的低辐射条件下的拦截水蒸发。除了机械湍流造成的森林粗糙度大，热诱导的湍流下冠层也被发现是负感热通量负责。利用该模型，数值研究了大体积冠层的蒸发效率与冠层内储水量的关系。结果表明，蒸发效率不仅是Rutter模型描述的储水量的函数，而且还取决于冠层结构和气象条件。
A 40-layer canopy model is compiled to investigate the micrometeorological aspects of rainfall interception over an evergreen broad-leaved forest. In this model, the evaporation of intercepted water and transpiration are calculated on a leaf basis as solutions of the energy budget equation, under the calculated microclimate within the canopy. Profiles of radiation intensity, wind speed, air temperature, and specific humidity within and above the canopy are calculated from a combination of equations for radiative energy transfer, atmospheric diffusion for momentum, sensible heat, and water vapor, and an equation of atmospheric turbulent kinetic energy. Through comparisons with laboratory experiments and field observations, the model was found to yield a good estimation of the evaporation from intercepted water on the basis of both a single leaf and the entire canopy. During a calculation, a negative sensible heat flux was simulated, exhibiting general agreement with observations, and providing the energy for the evaporation of intercepted water under low-radiation conditions. In addition to the mechanical turbulence resulting from the large forest roughness, thermally induced turbulence beneath the canopy is also found to be responsible for the negative sensible heat flux. Using the model, numerical studies are conducted to examine the relationship between the evaporative efficiency of a bulk canopy and the water storage within. Results show that the evaporative efficiency is not only a function of water storage as described by the Rutter model, but also depends on the canopy structure and meteorological conditions.