Andreia Medeiros de Lima
Abstract:
The aim of the research was to analyze rainfall on a regional scale and to compare temperature, relative humidity and rainfall on a local scale outside of the Semideciduous Seasonal Forests (FES) and within the FES, in the area of the Hydroelectric Power Plants basins. (UHEs) of Barra dos Coqueiros and Caçu, on the lower course of the Rio Claro, in Cachoeira Alta and Caçu municipalities in Goiás state. Rainfall data were obtained from four rainfall stations of the National Water Agency (ANA), (Cachoeira Alta, Itarumã, Quirinópolis and Pombal) from 1977 to 2011 and from the experiment outside the Semideciduous Seasonal Forests (FES), with temperature and relative humidity and rainfall measurement and inside the FES with temperature and relative humidity of September 2011 to September 2012. Methodological procedures were performed at regional, local and microclimatic scales, with calculation of standard years, statistical calculations, analysis of land use, slope exposure and comparison of climatic elements between the outside and inland points of the FES, starting from a reference point. In the regional scale, in 35 years of the averages of the four seasons, it was identified that 66% were rainy, rainy and usual standard years; The spatial variability of rainfall presented the highest concentration to the northwest and southwest of the basins and the climatic trend indicated a tendency of increase in the Cachoeira Alta and Pombal stations and decrease in Itarumã and Quirinópolis. In the local scale, in relation to land use, of the total area of 965 km2 of the two basins, it was found that the biggest change occurred due to the increase of the area occupied by water, in 2009 it was 0.6% and in 2011 it becomes occupy 7.4%, representing an increase of 1200%, with loss of native vegetation and habitat. Regarding temperature and relative humidity at the reference point outside the FES (P1), there were differences in the absolute maximum temperature of 10.6 ° C and the absolute minimum of 7.8 ° C; the absolute maximum relative humidity had differences smaller than 1% and the absolute minimum differences of 8%; in relation to rainfall, the largest difference was 927 mm. At the reference point within the FES (P15), the largest difference in the absolute maximum temperature was 10.5 ° C and the minimum 2.4 ° C; the absolute maximum relative humidity was 3% and the minimum 8%. In the microclimatic scale, the points outside the FES, especially those facing the north, northeast, west, northwest and southwest, which receive higher insolation, presented higher maximum temperatures between 52.7 to 46.9 ° C, while the points located within the FES, regardless of the exposure of the slopes, had the absolute maximum temperature between 36.7 to 47.2 ° C and the absolute minimum between 3.8 to 6.5 ° C. Thus, the points inside the FES showed attenuating effect on the microclimate, with the absolute maximum temperatures and thermal amplitude being lower and the absolute minimums and relative humidity being high.
