Análise da severidade de secas no Norte de Minas Gerais

Abstract

Drought, as other natural disasters, is phenomena of economic, social, technical and political. In Brazil, for centuries, drought or drought affects not only northeast, but also is present in the southeastern region, in Minas Gerais, and more significantly in the North of Minas Gerais and in the Valley of Jequitinhonha and Mucuri. Specifically in the North of Minas Gerais, a region characterized primarily by the uneven distribution of rainfall during the year and high evaporation rate, there may be years of drought, with effects observed in all areas of this middle region and years, in which the drought problems are verified only in some areas. In this sense, it is important to understand and identify the elements and climatic parameters which are related to the drought and drought phenomenon to support mitigating actions to minimize its effects on society. And before the common problem and in view of the lack of studies on the intensity of drought, this study aims to evaluate and compare the results to validate the Drought Index Bhalme & Mooley with the Rain Anomaly Index developed by Rooy, for climatic conditions of the state North of Minas Gerais and surrounding municipalities, relating the results to the parameters of the Water Balance climatological proposed by Thornthwaite e Mather (1955) and aridity indices, using historical climate data from the National Institute of Meteorology - INMET available to thirteen (13) municipalities of this region and surroundings. The development work was based on methodological procedures aimed behavior analysis of the amount of rain measured in (mm) and the measured air temperature values (° C). He attempted to organize and systematize a database of weather event data from historical data to study and estimate the intensity of water deficit affects the studied area. The objects of this study municipalities, located in the middle region North of Minas and surrounding municipalities were chosen based on the availability of meteorological data that would enable the calculation of the indices by the methodologies proposed. The results showed that the indexes Bhalme & Mooley - BMDI and Rain Anomaly - IAC found showed behaviors coincide with the reality of droughts and drought occurrences in the study area, and may this time be considered as good drought indicators. It was observed in the analysis of Rain Anomaly Index (IAC) to the region North of Minas and surrounding municipalities, the occurrence of negative precipitation anomalies in 11 (eleven) of the municipalities surveyed, especially in the outer years analysis. The municipalities of Montes Claros and Januária presented the greatest periods in consecutive months of negative precipitation anomalies. This coincides with the predominance of dry years and with a higher number of surveyed data, which were verified by quantitative droughts municipality, usually 53 years of drought, on average. The same pattern of temporal variations of the dry was also observed for the analyzed results with Bhalme & Mooley Index - BMDI, showing both dry contents analyzed in this study, separately or together, can be considered as good indicators for analysis severity dried