城市及乡村大气边界层结构的数值模拟

Numerical Simulation of Atmospheric Boundary-layer Structureover Urban and Rural Areas

建立了一个研究城乡非均匀下垫面陆面物理过程与大气边界层相互作用的模式。模拟了城市及郊区、乡村下垫面的地面热量通量、地表温度、混合层高度及大气边界层结构等特征。对城乡之间的差别进行了对比。模式主要依赖于以下参数和物理量 :地面反照率、下垫面粗糙度、土壤的可含水量、下垫面的热容量和热扩散系数、云量等参数。结果表明 ,本模式能合理地模拟不同地表热量平衡、地表气温、混合层高度、湍流交换系数、湍流动能、位温廓线等 ,以及它们的日变化。该模式所取参数主要针对北京市 ,时间为九月初 ,对于其他城市 ,参数应作相应的调整。本模式还可以用于其他均匀或非均匀下垫面的模拟。

A transfer model is established,which can be used to study the interaction between the land surface physical processes of inhomogeneous region and the structure of atmosphere boundary-layer over urban and rural terrains.The model has simulated surface heat flux,surface temperature,temperature profiles,height of mixture layer and so on.And the differences between urban area,suburban area and rural area have been compared.This model mainly depends on the parameters below:surface albedo,surface roughness coefficient,moisture available coefficient of soil,thermal capacity and thermal diffusion coefficient of terrain,cloudage.The result shows that this model can simulate the structure and eigenvalues of atmosphere boundary layer and their changes in a day.Parameters used in this model aim at Beijing City,and the time is at the beginning of September.To other cities,or other time,the parameters should be adjusted accordingly.In addition,being adjusted,the model can also be used for other homogeneous and inhomogeneous terrains.