Patterns of coverage and land use and their influence on the air temperature in Rio Claro, SP

Abstract

Changes in the coverage patterns and land use in a given place result in changes in air temperature. From this premise, this study aimed to analyze the air temperature gradients in five sites with different coverage patterns and land use, situated between the State Forest Edmundo Navarro de Andrade (FEENA), Rio Claro (SP), and the urban area of the same municipality. Between September 2010 and August 2011, the air temperature was measured every 30 min by dataloggers in five sites with different land use patterns: 1) forest of native trees, 2) eucalyptus reforestation with understory native trees, 3) eucalyptus forestry, 4) industrial mixed urban, commercial and residential areas, and 5) residential and commercial urban area. After data consistency, statistical analyses of position, dispersion, regression/correlation, and time series were performed. The results are shown in tables, graphs and spatial-temporal diagrams and reveal the thermal structure and its relationship with the coverage and land use patterns. Urban settlement patterns have higher temperature variations when compared to forest of native trees, with mean deviation of 1.7 ºC in the fall and spring, and 2.0 ºC in the summer and winter. In several cases, the small altitude variation among the posts of the FEENA was enough to mask the influence of differences in the vegetation, indicating that the topoclimatic effect overlapped the microclimatic one under certain weather types. In urban areas the topoclimatic effect was not strong enough to mitigate the influence of changes in coverage and land use, and of the energy dissipated by urban dynamics. Its influence can be seen in the differences in temperature range, the deviations of the temperature of the native forest trees, and in the change in the thermal rhythm related to heat dissipation from human activities (seven-day cycle).