Variabilidade interanual da precipitação em cidades do semiárido brasileiro.

Abstract

Rainfall variations affect the economy of a region directly. The semi-arid region in northeastern Brazil suffers drastic effects of such variability, which harms the agriculture and the availability of water resources. Were analyzed the influence of global climate variability modes in semiarid cities of rainfall in the states of Pernambuco, Paraíba, Ceará and Rio Grande do Norte. It was also analyzed the phenomenon of dry spells, adopted as a period of at least four consecutive days without rain within the rainy season. The data used in this stage consisted of daily precipitation series of 6 (six) stations located in the states of Ceará, Paraíba and Pernambuco. The climatology of 70 (seventy) locations throughout the four states and the correlation of the rainy season of these stations with El Niño, La Niña and the Atlantic Dipole were performed. Most stations showed five months of rainy season, from January to May. The Ceará region was the most affected by the interannual variability patterns. The variability of patterns affected the four studied states in different ways, however, the rainy seasons in the whole region suffered a large influence of the SST anomalies of the South Atlantic Tropical Basin. In El Niño years strong, the occurrence of dry spells is constant, they are of a lasting nature (reaching the mark of 60 days without rain) or shorter, but more often.