Collaborative Research: Lagrangian Modeling of Dispersion in the Stable Boundary Layer and Canopy Environments

摘要

The objective of this research was to improve our understanding of dispersion in the planetary boundary layer (PBL) by extending our Lagrangian particle dispersion model (LPDM) to the stable boundary layer (SBL) and to PBLs interacting with vegetation canopies. The LPDM was driven by large-eddy simulations (LESs). For the SBL, dispersion simulations of a weakly stable PBL demonstrated the slow dispersion rate caused by the stable stratification and showed that the LPDM produced plume features in good agreement with observations. These included plume ''tilting'' due to wind direction shear, plume spread, and the downwind concentration distribution. For a neutral PBL with a resolved forest canopy, the LPDM demonstrated enhanced vertical dispersion but reduced effects of directional shear on lateral dispersion by comparison to a reference no-canopy case. More detailed canopy studies were initiated by coupling the LES with a newly developed multi-layer canopy version of the NOAH land-surface model; initial results showed that the modeled canopy- imposed heat source accurately reproduces that obtained from the recent CHATS field experiment.