Numerical Study on Absorptive Characteristics both Mass and Momentum in Canopy Layer
冠层内动量和物质吸收特征的数值研究

A coupling model both mass and momentum exchange between canopy layer (CL) and atmospheric boundary layer (ABL) is developed in the paper. Diurnal variations and vertical distributions both mass and wind speed in CL are simulated with the model. The results show that the model can well describe the secondary maximum wind and multiple limits of the concentration distribution in the low CL due to the additional larger- scale diffusion, the rapid decrease of both turbulent flux and mass concentration with the decrease of height in CL, and the obvious effects of the CL momentum decrease on the concentration distribution. The simulating results are consistent with experimental data. Based on the similarity hypothesis of concentration to temperature profiles, the empirical relationship of mass sink height is derived.