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An Exploratory Study on Building, Traffic and Temperatures Rising in Porto Alegre City - Brazil
Published: 08 November 2011 by MDPI in The 1st World Sustainability Forum session Remote Sensing for Sustainable Management of Land and Biodiversity
Abstract: Climate change is a global phenomena that carries strong and sensitive effects at local scales, especially in cities, where more than 50% of world population is nowadays settled (Harlan and Ruddel, 2011). Urbanization is featured by intensive building, specifically by edification density and shape (Emmanuel, 2005, Hasenack, 1989), as well as by high rates of vehicles circulation in cities (Gu et al., 2011), two dynamic systems whose combination can contribute for temperatures increasing in crowded areas, as registered by Bentley (2007), Kim and Kim (2011) and several other authors. We studied the situation of Porto Alegre, placed in the Southern Brazilian State, at 30°2\'0" South and 51°12\'0" West coordinates, regarding these three aspects. Analysing side by side statistical data of real estate local institution (SINDUSCON) on building indexes, vehicles fleet and temperatures variation, given respectively by State Traffic Authority (DETRAN) and the National Institute of Meteorology (INMET), it was possible to identify expressive rising in these variables along the last decade. Building data were available for the 12 past years. They have shown an increase of 52,72% from 1998 to 2008 taking in account the number of new edifications in the city. Data from 2009 and 2010 for building were overlooked as atypical because of the impact suffered from financial global crisis. Vehicle fleet has experimented an increase of 54,37% with respect to the number of circulating unities from 2000 to 2010. Annual average temperatures grew 0,3ºC – from 19,5ºC between 1990 and 1999 to 19,8ºC between 2000 and 2009. In order to face constraints related to missing data, and to understand the changing patterns of land occupation in the last decade, we compared satellite images captured by Landsat in 2000 and 2010. Using geoprocessing techniques, we identified patterns of expansion in built area of the whole city, markedly to South direction. Considering that the population of Porto Alegre is keeping an average growth rate of 6% from decade to decade since 1990, reaching to 1,4 million of indwellers in 2010, according the Sate Economic and Statistical Foundation (FEE/RS), we can take population growth as not so relevant as the increase observed in building and vehicles fleet. Although any strong conclusion cannot be stated from this analysis regarding temperatures rising determinants, we suggest that building and fleet vehicles variation deserve more attention in terms of monitoring by local authorities responsible for urban planning in order to avoid losses for quality of life in the city.
Keywords: urbanization, building, vehicles fleet, air temperature, urban planning