Characterizing the Role of Moisture and Smoke on the 2021 Santa Coloma de Queralt Pyroconvective Event Using WRF‐Fire

Abstract

Smoke from wildfires or burning biomass directly affects air quality and weather through modulating cloud microphysics and radiation. A simple wildfire emission coupling of black carbon (BC) and organic carbon (OC) with microphysics was implemented using the Weather Research and Forecasting model's fire module. A set of large‐eddy simulations inspired by unique surface and upper atmospheric observations from the 2021 Santa Coloma de Queralt Fire (Spain) were conducted to investigate the influence of background conditions and interactions between atmospheric and fire processes such as fire smoke, ambient moisture, and latent heat release on the formation and evolution of pyroconvective clouds. While the microphysical impact of BC and OC emissions on the dynamics of fire behavior is minimal on short time scales (<6 hr), their presence increased the cloud water content and decreased the rain rates in our case study. In our case study, atmospheric moisture played an important role in the formation and development of pyroconvective clouds, which in turn enhanced the surface winds (8%) and fire spread rate (25%). The influence of fuel moisture on the pyroconvective cloud formation is smaller when compared with the atmospheric moisture content. A better representation of cloud processes can improve the mesoscale forecasts, which is important for better fire behavior modeling.

Triggering Pyro-Convection in a High-Resolution Coupled Fire–Atmosphere Simulation

“…Furthermore, the authors highlighted the sensitivity of deep moist convection to fuel load, and then to heat flux [9]. Concerning the fuel moisture content, it has a small influence on the formation of pyro-clouds, with atmospheric moisture availability being the main factor favoring the development of these clouds [44].…”

The Role of Fuel Characteristics and Heat Release Formulations in Coupled Fire-Atmosphere Simulation

“…While various studies have been conducted to assess the performance of WRF-Fire in simulating landscape-scale fire behavior and its sensitivity to various modeling parameters and assumptions (e.g., [11,[20][21][22][23][24][25][26][27]), no study exists that incorporates the parametrization of canopy and coarse woody materials in WRF-Fire to evaluate the relationship between fire energy and WRF-Fire simulated fire-weather. Kochanski et al (2013) assessed the performance of WRF-SFIRE, which is a variation of WRF-Fire with the same fire behavior model, when simulating the FireFlux I prescribed burn [25].…”