The Guaratinguetá region in São Paulo, Brazil, located in the Vale do Paraíba, a strategic economic region given its location in the industrial/technological hub between the cities of Rio de Janeiro and São Paulo. It features tropical climate and distribution of rainfall influenced by frontal systems, orography, convective rainfall, the continental influence and sea breezes, thus making it a highly productive region nationwide. The purpose of this article is to subsidize planning management of water resources, and the exploitation of water in various sectors, as well as serve as a reference for civil works and climate studies, looking to improve the use of activities that depend on the utilization of water in the region, therefore improving the quality of life of the population.
The used and properly compiled meteorological data were obtained from the Aeronautics Ministry Meteorological Station, the Department of Water and Energy of the State of São Paulo and the National Institute for Space Research. The data were analyzed according to the Gumbel distribution/methodology. The study was performed by addressing the overall period (1974-2012), the period in decades, and the seasonal period (1962-1991). The results show an increasing trend of average rainfall through the detailing in decades. The interval also showed an average cyclic rainfall, high and low cycles that alternate. In the second set of details, based on the seasons of the year, the averages behave according to the season for highland tropical climate, with summer having greater rainfall, followed by spring and autumn and winter with the least rainfall.
Knowing that there is a change of the rainfall regime, it is necessary to have better forecast of works in the region, more detailed monitoring, as well as government precaution tools. The major concern with global warming, and with water scarcity already pointed out in several regions of the world, makes it necessary nowadays to get a response based on microclimates, considering this effect. As the planning management of water resources, and the exploitation of water in various sectors are normally of the competence of public entities, the aim is to cooperate and provide data for such entities.