THIAGO ROCHA
AUTHOR: THIAGO ROCHA
TITLE: CLIMATE VARIABILITY IN THE MIDDLE CAIAPÓ WATER BASIN, GOIAN WEST - GOIÁS/BRAZIL (VARIABILIDADE CLIMÁTICA NA BACIA HIDROGRÁFICA DO MÉDIO CAIAPÓ, OESTE GOIANO – GOIÁS /BRASIL)
ADVISOR: Prof. Dr. Zilda de Fátima Mariano (in memoriam).
DEFENSE DATE: 08/27/2018
ABSTRACT:
Based on the genesis and atmospheric dynamics, several cause and effect relationships can be evidenced in the set formed by the atmosphere and the surface. Although the climate is governed by the action of solar radiation and natural surface factors, human action, through the forms of land use and occupation in space, has been causing climate change, especially at local scales. The study was carried out in the Middle Caiapó watershed, Goian West between the geographic coordinates of 16° 22′ 40″ and 16° 25′ 21″ south latitude and 51° 20′ 58″ and 51° 04′ 28″ west longitude. The aim of this research is to analyze the climatic variability of rainfall by relating it to atmospheric systems at the regional scale and air temperature (ºC) and rainfall (mm) at the local scale, cited by Ribeiro (1993), relating to the physical-geographical elements (geomorphology, hypsometry, slope, slope exposure and land use). Regional rainfall data were obtained from the National Water Agency (ANA) rainfall stations in the historical series from 1974 - 2016 (42 years). In order to obtain local data, 7 thermohygrometers (to record air temperature (ºC)) and rainfall (to collect rainfall data (mm) were installed. Data were tabulated in Excel spreadsheets. The results of the regional precipitation were: in the average rainfall spatialization there was an accumulation of precipitation in the North and West portions of the study area, and a decrease in precipitation in the southern and eastern portions of the basin; the rainfall variability of the 4 rainfall stations, in the regional scale, it was verified that in Piranhas-GO it obtained an average of 1,661.5 mm (42,86%) registered above average and (54,14%) below; the Córrego do Ouro (1,539.3 mm) and Montividiu-GO (1,457.8 mm) stations obtained the same results of 47.61% above average and 52.39% below average; the trend of precipitation over the 4 stations, there was an insignificant correlation because the value of R² was less than 1; In the standard years 1980 was classified as “rainy” with rainfall above 2,000.0 mm, in 1990 it was classified as “dry” for all posts (875.9 to 1,013.6 mm). This variability of precipitation is related to regional atmospheric systems; and on the regional atmospheric conditions and the daily maximum and minimum absolute air temperature (ºC) variability and local rainfall (mm) it was found that the maximum temperatures registered their highest values in the months of September, October and November under the action of the South Atlantic and Continental Tropical masses, causing high temperatures, in P1 were registered 49.2 ºC and, in P7, 46.1 ºC in September/2017. The minimum temperatures were recorded in June, July and August/2017, under the influence of cold fronts, in which the temperature decreased, being the lowest value recorded in P7 - 7,0 ºC in July/July. 2017 Rainfall is heterogeneous, the collection point P5 recorded the highest monthly precipitation in November/2016, with 411.6 mm, the month in which it is associated with the southward shift of the South Atlantic Convergence Zone (ZCAS). The lowest total monthly rainfall in the study area was 5.3 mm for July/2017, during this period the masses are characterized as dry and cold. Regarding the spatialization of the maximum and minimum absolute temperatures, an interrelation of the physical-geographical elements was observed; P1 recorded the highest temperatures (47.3 ºC; 48.0 ºC; 49.2 ºC) located at the eastern end of the basin and associated with land use, hypsometry, geomorphology, slope and slope exposure. The P5 located in the extreme north of the basin presented the maximum monthly absolute temperature of (43.6 ºC, 44.5 ºC and 45.8 ºC) associated with the topoclimate factor, which is the highest point of the basin (834 m). Absolute minimum temperatures were concentrated in the center of the basin, at P3 and P7, which are lower points, located in valley bottom, with pasture land use; At these points, P3 - 8.4 ºC and P7 - 7.0 ºC were recorded in July/2017.
