Canopy Wind Models for Complex Terrain in the Fast-Response QES Framework

The flow dynamics within a vegetated canopy is affected by factors such as the height, density, distribution of the vegetation, weather conditions, and terrain. Evaluation of wind-speed reduction created by the drag induced by the vegetation is critical to study the effects on other environmental factors such as temperature, humidity, or particulate transport. In addition, complex terrain can have a significant impact on the flow within the canopy. Models that can accurately simulate these situations at a small computational cost remain a significant challenge.

QES (Quick Environmental Simulation) is a fast-response framework designed to quickly and accurately predict wind field, turbulence, and particle transport for applications in atmospheric boundary layer research such as urban air quality, wildfire spread, and pathogen propagation in agricultural systems. QES wind-diagnostic model uses conservation of mass and empirical parameterizations to simulate flow in complex geometries such as urban areas, vegetated canopies, and complex terrain. QES canopy models are modified to capture the interaction between the terrain and vegetative canopies. We present how the modified models affect flow and scalar transport in neutrally stratified atmospheric boundary layer. We show examples of applications of the model in wildfire spread and powdery mildew transport in vineyards.