森林冠层和森林边界层大涡模拟

在采用各向异性湍流动能闭合方案和3阶Runge Kutta时间积分方案的大涡模式中，引入由森林冠层粗糙元造成的动量拖曳项、热量输入项和TKE耗散项，以模拟森林冠层和森林边界层的气象场. 通过中性和不稳定层结条件下不同叶面积指数算例的模拟分析及与已有观测结果的比较表明，本文所建大涡模式对森林冠层和森林边界层有较好的模拟效果. 进一步研究表明：不稳定层结条件下较稠密的森林冠层中特有的Kinking & Pairing湍涡结构与森林边界层中湍流的大涡运动相互作用，形成了森林冠层附近的温度斜坡型结构.

Large eddy simulation of turbulent flow in the forest canopy and the forest boundary layer.

Based on a large eddy simulation (LES) model with anisotropy subgrid scale closure model and an explicit multi-stage third-order Runge-Kutta scheme, the drag term on momentum, the heat source term and the production term of turbulent kinetic energy (TKE) imposed by the canopy elements are introduced to the LES equations to simulate the meteorological field in the forest canopy and the forest boundary layer. The analysis of simulation results and the comparison with observational data show that the LES model simulates the turbulent flow in forest canopy and forest boundary layer very well. Further research indicates that, under unstable stratification, the turbulent structure of Kinking and Pairing in the dense forest canopy, together with the large eddy structure in forest boundary layer, forms the temperature ramp near the forest canopy.