Study of mega fires in Portugal: surface, atmosphere and society perspectives

Abstract

A mega fire is a transversal problem to several fields, with impacts from the Earth’s atmosphere to human health and safety, quality of life and economic growth in affected areas. The study summarizes some recent studies developed at University of Évora, Portugal, covering the following areas: surface, atmosphere, and society. At surface, the study has been essential to understand the vegetation dynamic and fire susceptibility. The surface characterization, namely the fuel load and moisture content are improved based on remote sensing from drone flights, satellite and in-situ observations. In the atmospheric context, the current state of the fire weather risk and its tendency for the future based on climate projections over the western Iberian Peninsula is also explored. The results show a fire weather risk positive trend and, in general, there is an increase in the frequency of years with extreme Fire Weather Index values. The state-of-art MesoNH atmospheric model is used to characterize the atmosphere in several mega fires case studies occurring in 2017, 2018 and 2019. Some simulations are coupled to a fire propagation model (ForeFire). In general, the simulations show the main atmospheric conditions that favored the extreme events, from large to local circulation including the presence of weather systems, such as dry thunderstorms. The cloud electrification and the forecast of cloud to ground lightning that can serve as ignition of forest fires, as well as pyro-clouds (PyroCu and PyroCb) have been studied from the simulations at very-high horizontal and temporal resolution. Finally, in the society context, the study based on questionnaires, explores the fire risk perception and their impacts on tourism in a national natural park, (the Vale do Guadiana, PNVG). The study helps to identify strategies for the management of the PNVG in order to mitigate the occurrence of forest fires. All these studies represent an effort to better understand the occurrence of mega fires in Portugal from different points of views and in a multidisciplinary framework.