Abstract

ESQUIVEL-ARRIAGA, Gerardo et al. Temporal analysis of droughts (1922-2016) in the upper Nazas River Basin using SPI and its relationship with ENSO. Tecnol. cienc. agua [online]. 2019, vol.10, n.5, pp.126-153.  Epub Feb 15, 2020. ISSN 2007-2422.  https://doi.org/10.24850/j-tyca-2019-05-05.

The Standardized Precipitation Index (SPI) allows measuring the severity of the drought during a given period. The main objective of this was to generate SPI series for the upper Nazas River Basin and to analyze the ENSO (El Niño-Southern Oscillation), climatic phenomenon influence on the modulation of the SPI variability. The monthly precipitation data of 17 stations distributed in the basin were taken into account. The SPI was generated for a 12-month time scale of the 17 stations where a common variability was determined in15 out of the 17 series. A regional series of SPI for the period 1922-2016 was generated, in wich the most severe drought in the basin was recorded in the 1950s and 2000s. The spectral coherence of waves analysis between the SPI and the El Niño 3.4 index indicates a relationship for the dry and wet periods recorded in 1920-1930, 1950 and from 1980 to 2005 with a statistically significant influenced (p<0.05) due to occurrence of ENSO in periods of 2 to 7 years, 2 to 3 years and 10 to 14 years, respectively. The knowledge of the ENSO influence on the modulation of the climatic variability at the basin level, represents critical information to implement water resources management strategies and to prevent short-term risks in the activities destined to the inputs’ production.

Keywords : Drought index; severity; hydrology; climatic risk.