Standardized Precipitation Index Variability in the Northern Region of Paraná State Associated with the El Niño - Southern Oscillation

Abstract This study aimed to evaluate drought variability based on Standardized Precipitation Index (SPI) in localities in northern region of Parana State and its relationship with El Niño-Southern Oscillation (ENSO). Rainfall of five meteorological stations 40 years time series, obtained from Agronomic Institute of Paraná, National Institute of Meteorology and Paraná Meteorological System. It was noted that El Niño and La Niña events influenced annual rainfall variability, however, showed less significant associations with dry extremes of SPI index. With significant reduction of rainfall totals, June to August period registered highest frequency of SPI categories moderately dry (18.3%), very dry (13.0%) and extremely dry (7.0%). The highest monthly drought frequencies were intensified, moderate, very and extremely dry, recorded at Apucarana station (83 events), followed by Maringá and Paranavaí stations (68 events), and Bela Vista do Paraíso (63 events) and Londrina (66 events), with lowest occurrences of drought events. Although, literature consulted indicates association between increase or reduction of rainfall totals during El Niño and La Niña events occurrence, Kendall, Spearman and Pearson correlations, and statistical parameters used indicated predominantly low correlations between results obtained from SPI - 1 month and ENSO in all regions studied.