植被微气象的数值模拟

NUMERICAL SIMULATION OF PLANT CANOPY MICROMETEOROLOGY

综合考虑梯度输送和阵性穿透作用，并对植被上方的过渡层作适当处理，提出了植被微气象的一阶闭合模型。它对温、湿、风等物理量垂直分布的模拟精度良好。引用系统优化理论和方法，对模型中参数作多维非线性搜索，结果客观可靠。由于植物本身的调节适应能力和反馈作用，大气与植被间的动量与水热交换机制和过程不尽相同。在动量输送过程中，梯度产生项和阵性穿透皆不可忽视，尤其在群体下部，更为重要；而在热量和水分输送过程中，阵性穿透作用在低矮密集植被中的贡献甚微，梯度产生项起主导作用。

he gradient production and gust ejection of turbulent transfer have been combined to develop a first-order closure model for simulating plant canopy micrometeorology and the above environment with reasonable consideratinn to the transitional layer above the canopy.The model simulates the vegtical distributions of air temperature, specific humidity, and wind speed within and above a tea canopy very well. Objective and reliable values of the parameters involved in the model were computed with nonlinear multidimensional approach algorithm employed from optimizing theory and method.All the mechanisms and processes in momentum and water and heat exchange between vegetation canopy and the atmosphere are different that is mainly owing to the adjustment.adaptation, and feedback of the plant to the variation of its environment. It is gradient production rather than gust ejection that causes water vapour and heat to move within a short dense plant canopy. while for momentum transfer. both of them are equally important. especially in the lower part of the canopy.