The influence of forest canopy characteristics on fire-perturbed atmospheric boundary layer

Prescribed or controlled burning, a viable technique for forest management, is known to perturb atmospheric boundary layer. The amount of perturbation, however, can be modulated by the canopy characteristics in the forests where the controlled burning is conducted. In this study, the Advance Regional Prediction System (ARPS) with a canopy submodel (ARPS-CANOPY) is used to explore the sensitivity of fire-perturbed boundary layer to differences in the canopy characteristics. A series of numerical experiments are conducted with a stationary low-intensity prescribed burning, represented in the model as a line of enhanced surface sensible heat flux, and with different plant area indices and canopy profile shapes. Numerical experiments are also conducted where gaps are introduced into forest canopy. The results from these numerical experiments suggest that the differences in canopy profiles (e.g., dense overstory vs. more uniformly distributed canopy) and the relative position of forest gaps to the prescribed burn location have a strong influence on fire-induced perturbations to the mean and turbulent flows and vertical and horizontal scalar fluxes.