Influence of El Niño and La Niña phenomena on seasonality of the relative frequency of rainfall in southern Amazonas mesoregion

Abstract

The global and Amazon climate change, mainly in rainfall, due to the El Niño and La Ninã phenomena. The objective of this study was to analyze the relative frequency (RF) of rainfall, in different periods of the day, during occurrences of El Niño, La Niña events and neutrality condition. The research was carried out in the Southern mesoregion of the state of Amazonas (Apuí, Boca do Acre, Lábrea, Manicoré and Humaitá). Data were analyzed by the Spiegel´s method. The rainfall data were obtained from the Global Land Data Assimilation database from January 1st, 2000 to December 31st, 2018. Data were made available every three hours and integrated into six hours. RF of rainfall was higher in the afternoon in La Niña, Neutro and El Niño years in all municipalities. The RF in La Niña year was higher than during El Niño. The RF during the Neutral year was higher than during El Niño in Apuí and Boca do Acre, and had no difference in Lábrea, Manicoré and Humaitá. The rainfall in the southern Amazon mesoregion was more frequent during the afternoon.

Riscos de geadas em cultivos de batata na região de Guarapuava-PR em diferentes fases do ENOS

“…A respeito de ocorrência de mais de uma geada concentrada no mesmo decêndio, Uma explicação provável para a ocorrência de eventos de geadas de maiores intensidades em períodos de neutralidade climática, conforme avaliado no estudo, está Research, Society and Development, v. 9, n. 11, e3309119925, 2020 (CC BY 4.0) | ISSN 2525-3409 | DOI: http://dx.doi.org/10.33448/rsd-v9i11.9925 relacionado ao fato, de esta fase ser instável e não apresentar um padrão estabelecido do comportamento de suas variáveis, podendo assim, ocorrer eventos extremos como na precipitação (Pedreira Junior et al, 2020). Maiores números de geadas em anos de neutralidade foram encontrados por Müller et al (2003), em situações com um centro de baixa pressão localizado no nordeste da área continental, simultaneamente com um sistema de baixa pressão acentuado em latitudes altas, favorecendo as condições mais frias e ocorrência de geadas.…”

Flow variability in the Araguaia River Hydrographic Basin influenced by precipitation in extreme years and deforestation

“…ENSO is the name referring to the El Niño and La Niña phenomena, which constitute the hot and cold phases, respectively, when there is anomalous heating and cooling of the sea surface temperature (SST) in the tropical Pacific, causing a decrease and an increase in atmospheric pressure in this region of the ocean (Pedreira Junior et al, 2020). Such thermal and barometric oscillations alter the circulation of winds, configuring in the northern Brazilian region and its surroundings as descending and ascending air movements, which induce a reduction and an increase in precipitation, respectively (Barichivich et al, 2018).…”

Spatiotemporal variability of precipitation and surface temperature in the southern mesoregion of amazonas, Brazil, during the occurrence of ENSO

“…It contributes to the availability of 70% of all Brazilian fresh water and provides important environmental services, such as storage and absorption of excess carbon from the atmosphere and transport of water vapor to the atmosphere (SILVA JÚNIOR et al, 2019;ROCHA et al, 2015). The Amazon is located in the equatorial region and has a hot and humid climate, where rainfall is the main climatic factor, as it distinguishes between wet and dry seasons (PEDREIRA JUNIOR et al, 2020). Variability in the climate pattern, whether due to deficiency or excessive rainfall, across the Amazon region, causes drought and flood events (MARENGO; ESPINOZA, 2016).…”