Climate changes in urban environments : trends and generations of heat islands in Presidente Prudente, Brazil

Resumo

Presidente Prudente is located at São Paulo State (Brazil), has a population of approximately 200,000 inhabitants and in the structure of the city, there are intra-urban environments completely different from the point of view of soil occupancy, especially with regard to the density of constructions, arborization standards of roads and backyards, green areas, circulation of vehicles and people. This survey had the purpose of verifying the trend of thermal
characteristics of the last 34 years and analyzing the intensity and shape of the
urban heat island. The materials and techniques used to develop this study were: temperature data (minimum, average, maximum, and recorded at 9 pm) in the period from 1971 to 2005, collected in the Meteorological Station of Presidente Prudente (INMET). They were statistically treated, and the methodology to verify the intensity and shape of the urban heat island consisted of the definition of two transects, with mobile measurements, using digital thermometers, coupled to the side of two vehicles, totaling 120 points of air temperature collection. The results showed that the temperatures have suffered significant increase, especially with regard to the absolute minimum values and the records at nighttime. Heat islands of high magnitude were also identified, with maximum intensity of 9.6ºC. The spatial variations occurred according to the types of soil occupancy and relief. This way, one concludes that in view of all the changes implemented in the natural environment, the energy balance has changed, coinciding with the global warming trend described by the IPCC published in 1994 and 2001.