Análise das ocorrências de granizo na região sul do país e estudo de viabilidade para implementação de sistemas anti-granizo em áreas afetadas

Abstract

The hail is an extreme atmospheric event that can cause serious damage that can account for millions of reais in losses for storms with only minutes long. In Brazil, the Southern Region is the most affected and the study of this phenomenon is of great importance to the states of Parana, Santa Catarina and Rio Grande do Sul. With greater understanding of it and knowing better the hail is possible to prepare and fight it to minimize the damage it causes. The present paper is a gathering and interpretation of information extracted from damage assessment documents (Avadan) of the Civil Defense of the States of southern Brazil for hail storms that came to cause damage to their municipalities. For Paraná and Santa Catarina the study period was from 1996 to 2012 and the Rio Grande do Sul and the South Region 2001-2012. With the information obtained in these documents was created a database containing the date, time, duration, diameter of the hydrometeors and the damage in the affected municipalities. After the treatment of the data was generated graphics of number of occurrences distributed monthly and hourly distributed for all the States. With the graphics, came to the conclusion that the occurrences are concentrated between the months of September and October in the afternoon and early evening. From geoprocessing data using ArcGIS 10.3 software were generated thematic maps of number of occurrences, losses and standardization occurrences for the three States individually and the Southern Region. Normalization was performed using the mean area of the municipalities of the subject matter and for a period of ten years. With the analysis of graphs can be noted that there is no direct relationship between the number of occurrences in the same municipality and losses, so, a municipality with fewer recorded events can accumulate more damage than one with more occurrences. A higher concentration of occurrences region was observed, more visible in the standardization maps, which defines an arc between the southwestern Paraná, west of Santa Catarina and northwestern Rio Grande do Sul. It was made a study of economic viability for the implementation of an anti-hail system in the city of Fraiburgo, the municipality with the highest accumulated losses of the study for the period 1996-2012. The silver iodide burner was the fighting method selected and were analyzed two indices of economic viability: the net present value and benefit-cost ratio. For both indicators the implementation proved quite favorably with the benefits exceeding by more than seven times the costs.