A influência do crescimento urbano na variação de temperatura no bairro de Val-de-Cans em Belém-PA

Abstract

These days, global, regional and local climatic changes represent one of the biggest concerns for humanity. Studies indicate that these changes can due to both natural and anthropogenic causes. The air temperature is one of the meteorological variables modified by it. This study aims to analyze the hourly variation of air temperature and dew point over 31 years, in the region located around the Belem International Airport. Air temperature and dew point hourly data were used and analyzed by period: I (1975-1984), II (1985-1994) and III (2003-2013). The 1995-2002 period was not made available for this study. The data analyses were carried out using hourly, monthly and yearly air temperature and dew point averages for each period. In the maximum and minimum daily temperatures, the Morlet Wavelet Technique was used to check the signal where temperatures have greater variability. In addition, satellite images for the years 1985 and 2013 were used to identify the percentage of green urban areas and Land surface temperature (LST) and the Effective Temperature Index (ET) for the thermal comfort analysis, both in the Val-de-Cans region. Over these periods, we could notice an increase of 0,4°C in the maximum temperature analysis and 0,9°C in the minimum temperature one. The daily maximum and minimum temperature presented intensity in the signal in the annual cycle which can be related to annual scale natural events that influence their own variation. We also verified that there was a reduction of about 665,7 hectares in green areas in the Val-de-Cans region, during 29 years. The results also showed a lower surface temperature in 1985 than in 2013. In 2013, we observed that as the urban areas increased, the green urban areas decreased, consequently increasing the heated areas. Through the Effective Temperature Index, we could verify the maximum values of TE in period III, in other words, thermic stress which is likely to have an impact on quality of life of human population and biodiversity. The thermal behavior seemed effectively influenced by the urbanization process.