Tempo severo e formação de tornado em Taquarituba/SP: uma aplicação do modelo WRF como ferramenta de análise.

Abstract

Tornadoes are considered sudden and violent phenomena that cause major environmental impacts on social infrastructure and human security. The simulations of this type of phenomenon through numerical modeling have been increasing during the last years, to try to discover patterns and/or indicators of the most favorable environments for its formation and in this way to try to minimize the damages that they can cause. The main objective of this research is to investigate the atmospheric conditions that favored the development and evolution of the severe storm that generated the tornado in the city of Taquarituba, SP on September 22, 2013. Satellite data, images from the meteorological radar of Bauru were used, data from surface stations and from the MERRA2 reanalysis. The WRF model was processed with three nested grids (18, 6 and 2 km) every 30 minutes and using input data from the GFS model. Four experiments were carried out using combinations of 2 cloud microphysics schemes and 2 planetary boundary layer schemes in order to find which of these combinations reproduced in a better way the atmospheric environment that triggered the severe event and to evaluate the sensitivity of the model in the representation of some thermodynamic parameters and atmospheric variables indicators of deep convection. The results showed that the presence of the Low Level Jet, with winds greater than 15m/s, together with the High Level Jet, confirming the coupling between them, had a great contribution to the generation of convective instability on the surface and consequently in severe storm and tornado development. All indices showed a significant change in value around the time of the tornado. Experiments 3 and 4 showed the best performance of the model in representing the atmospheric conditions that favored the formation of the severe event, showing that the PLC parameterization schemes significantly influenced the development of the atmospheric conditions that generated the severe storm in Taquarituba.