Análise da habilidade preditiva da precipitação com ênfase na seca meteorológica no nordeste brasileiro

Abstract

Of the adverse natural phenomena, drought is what most affects society because it acts over large territorial extensions and lasts for long periods of time. Drought is a phenomenon characterized by a water deficit long enough to impact on edaphic, meteorological, water and social factors. The prediction of drought has contributed worldwide to actions to mitigate the impacts of the phenomenon and increase resilience. Brazil has the largest inhabited semi-arid territory in the world: the Northeast. With each drought that occurs in the Northeast of Brazil (NEB), water rationing, loss of crops, death of animals and hunger of part of the population are registered. The impacts of drought provoke a great rural exodus to the coastal cities of NEB and even to large urban centers in the country. Several studies have been conducted to understand the dynamics of drought in NEB. It is known that the occurrence of the phenomenon is partly modeled by the El Niño Southern Oscillation (ENOS) and partly by the Sea Surface Temperature (SST) of the Tropical Atlantic. Such oceanic phenomena of slow variability allow to anticipate with some quality the accumulated rain and the average temperature of the following months. This work analyzed the predictive ability of precipitation with an emphasis on meteorological drought in Northeast Brazil in order to sediment a methodology that contributes to coping with drought using the most advanced operational products of the North American model set. In general, the results show that the NEB precipitation predictive ability is good enough to generate operational forecasts in the region. The northern sector of NEB showed the best results between the periods analyzed. In this sector, the predictive ability of precipitation extends beyond its rainy season. Followed by the northern sector comes the eastern and southern sectors with considerable dexterity in their respective rainy periods. The central region, in turn, represented by the northeastern semi-arid region, showed the worst results, where the dexterity of precipitation forecasts in this sector is particularly difficult. Thus, the precipitation conditions associated with meteorological drought in the NEB have reasonable forecasting potential and the model can be used in an operational way to assist actions to deal with drought.