Impactos do La Niña2020-2022 nas variáveis meteorológicas no estado do Amazonas

Abstract

The La Niña phenomenon, characterized by anomalous cooling in the Equatorial Pacific, alters atmospheric circulation and the global climate. In Brazil, it intensifies rainfall in the northern and northeastern regions, causes droughts and heat in the south, and affects family agricultural production in the Amazon, especially in the state of Amazonas. Therefore, the objective of this study was to evaluate the influences of La Niña on temperature, precipitation, and relative humidity variables in the state of Amazonas from 2020 to 2022. The data related to the studied variables were obtained from the ERA5 and CHIRPS reanalysis products, processed into monthly and annual averages from 2020 to 2022, and manipulated using Python programming language libraries. Anomalies were calculated by subtracting current records from the 30-year climatological normal (1980–2010). Precipitation had its lowest annual value in 2020, while the highest rainfall was recorded in 2021 and 2022 (2,850.32 mm/year and 2,685.42 mm/year), respectively. There were negative precipitation anomalies throughout most of 2020 and positive anomalies in 2021 and 2022, ranging between 200 mm and 700 mm. Air temperature had the highest annual average recorded in 2020 (26.7°C), and in 2021 and 2022, the annual average temperatures remained similar. Positive temperature anomalies were more evident in 2020, ranging from 0.2°C to 1.9°C above the historical average. Relative humidity had an annual average of 83.2% in 2020, while in 2021, values ranged from a maximum average of 88.7% in December to a minimum average of 74.17% in August. In 2022, there were no significant variations, with an average of 83.01% for the year. All variables analyzed in this study were influenced by La Niña and varied according to the intensity of this event. However, the La Niña event was classified as weak.