Collaborative Research: Lagrangian Modeling of Dispersion in the Stable Boundary Layer and Canopy Environments
Final rept. 1 Oct 2004-31 Aug 2008
COLORADO UNIV AT BOULDER COOPERATIVE INST FOR RESEARCH IN ENVIRONMENTAL SCIENCES
Pagination or Media Count:
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.
- Fluid Mechanics