Abstract
This study analyzes fire-induced winds from a wind-driven fire (Thomas
Fire) and a plume-dominated fire (Creek Fire). Two numerical
experiments, one without the fire present and the other with the fire,
were used. The fire-induced perturbations were then estimated by
subtracting a variable value in the “No Fire Run” from the “Fire
Run” (Fire - No Fire). For this study, spatial and temporal variability
of winds, geopotential height, and convergence were analyzed.
Furthermore, cloud water mixing ratio, precipitation, and fuel moisture
were analyzed during the Creek Fire to assess fire-induced rainfall and
its impact on fuel moisture. It was found that the wind-driven Thomas
Fire created more widespread and generally stronger fire-induced winds
than the plume-dominated Creek Fire. In addition, fire-induced wind
speeds during the Creek Fire followed a diurnal cycle, while the Thomas
Fire showed much less temporal variability. When analyzing geopotential
height, the results were very similar to other idealized simulations. A
localized low-pressure region was observed in front of the fire front,
with a preceding high-pressure area. When analyzing precipitation, it
was found that the fire increased precipitation accumulation in the area
surrounding the active fire. This created an increase in fuel moisture
which could have helped locally decelerate the fire spread. Further
research into the processes behind fire-atmosphere interactions will
lead to a better understanding of fire behavior and the extent to which
these interactions can impact the fire environment. These studies will
help assess the limitations of uncoupled operational models and improve
fire modeling overall.