EVALUATION OF URBANIZATION ON AIR AND SURFACE TEMPERATURES IN THE METROPOLITAN REGION OF FORTALEZA – CEARÁ
Urban climate. Urbanization Effect. Mann-Kendall test. Land Use Land Cover. Land Surface Temperature. Normalized Difference Built-up Index.
The Metropolitan Region of Fortaleza, in the state of Ceará, has an approximate population of 4.051 million inhabitants, more than half of this population is concentrated in Fortaleza. Urbanization, the way in which the land use and occupation process takes place, leads to the formation of a climate of its own, which influences the way of life of the population in these areas. The increase in urban population has generated anxieties about the study of local and regional climate change in an attempt to understand the relationship between anthropogenic activities and possible changes in climate. In this way, the objective of this research was to investigate the effect of urbanization on air and surface temperatures in the Metropolitan Region of Fortaleza-CE (urban station) and Jaguaruana (rural station). In order to do so, first, we used the observed data of the monthly mean maximum and minimum air temperature of meteorological stations of the National Meteorological Institute for the period from 1980 to 2017, and satellite images of Landsat 5-Thematic Mapper and Landsat 8- Operational Lande Imager/Thermal Infrared Sensor for July 2006 and August 2017, respectively. Thus, the parametric (Simple Linear Regression) and non-parametric methods (Mann-Kendall and Theil-Sen) were used to investigate the tendency of air temperature in urban and rural stations; maximum likelihood-supervised classification method for land use change and land cover (Land Use Land Cover); The Normalized Difference Built-up Index for mapping urban areas. As well as, some steps of the Surface Energy Balance Algorithms for Land method were used to obtain the Land Surface Temperature estimation. The results obtained for the air temperature showed that: (i) a positive linear trend was observed in the mean maximum temperature for the urban station of 0.37°C/decade, while for the rural season, the trend was positive for the mean minimum temperature, but not statistically significant; (ii) the urbanization effect in relation to the mean maximum temperature between urban and rural stations was 0.11°C/decade. (iii) For surface temperature, the year 2017 showed a difference of 4.5°C in the temperature between the urban and rural stations, as Land Land Land Cover increased in both regions for the years 2006 and 2017. (iv) The Normalized Difference Built-up Index showed an increase in temperature in relation to the built area for both the urban and rural stations, which was 2.5°C higher than that, about. However, this index does not accurately differentiate urban area from exposed soil, since these surfaces have similar spectral responses to built-up areas.