The Impact of Different Phases of the El Niño-Southern Oscillation Phenomenon on Goiás State Rainfalls and Temperature Characteristics Across Three Decades

Abstract

Rainfall and temperature are the two key parameters of crop development. Studying the characteristics of these parameters under El Niño-Southern Oscillation (ENSO) conditions is important to better understand the impacts of the different phases of this phenomenon (El Niño, Neutral, and La Niña conditions) on agriculture. This study analyzes 32 years (1980–2011) of climatic data from 128 weather stations across Goiás State in Brazil to determine the behavior of temperature and rainfall time series over three periods (1980–1989; 1990–1999 and 2000–2011) under El Niño, Neutral, and La Niña conditions. The analysis revealed no major impacts of ENSO conditions on accumulated rainfall characteristics, a feature particularly marked in the most recent period (2000–2011). ENSO impacting temperature was identified but presented considerable variability across the periods investigated. These impacts were marked in the first two periods as for maximum temperature and increased from the first to the last period as for minimum temperature. These features were noticed in both analyses in the entire Goiás State and most of the investigated mega-regions, except for the East and Northeast mega-regions as for minimum temperature. There were increases in maximum temperature values throughout the rainfed season (October to March) for all ENSO conditions and investigated periods. Minimum temperature also increased across the three investigated periods, and this was marked in the beginning of the rainfed season (October) under El Niño and Neutral conditions.