Modelação da piro-convecção durante mega incêndios em Portugal

Abstract

In 2017, Portugal was affected by several wildfires that exhibited extreme behaviour. To investigate the pyro-convective activity in two megafires that occurred in 2017, two numerical simulations were carried out with the Meso-NH atmospheric model coupled to the ForeFire fire propagation model. The experiments were configured for three nested domains of horizontal resolution of 2000 m, 400 m, and 80 m. The vertical grid is composed of 50 height-based terrain-following levels. Heat and water vapour fluxes were emitted into the atmosphere and carried out by ForeFire, which allows the fire front temporal evolution calculation, considering the terrain slope, atmospheric properties, and fuel characteristics. The simulations were performed in a one-way coupling, i.e., the fire front evolution is directly imposed from a pre-defined map obtained from official reports. The simulations showed that coupling the atmospheric model with the fire propagation model allows exploring the fire impacts on the atmosphere, namely the clouds formation inside the smoke plume. In the Quiaios megafire, the simulation indicated the formation of a pyroCu cloud, while for Pedrógão Grande it was possible to verify that the pyro-convective column produced a pyroCb cloud.