Seasonal variability of the Intertropical Convergence Zone and its influence on northern South America

• Main Authors: Reis Ribeiro, Reinaldo Matheus, Vitorino, Maria Isabel, Moura, Mauricio do Nascimento
• Format: Article in Journal/Newspaper
• Language: Portuguese
• Published: Universidade Federal de Pernambuco 2023
• Subjects: ZCIT; Climatologia; Circulação atmosférica; Índices climáticos; Regime pluviométrico; Meteorologia Sinótica; North Atlantic
• Online Access: https://periodicos.ufpe.br/revistas/index.php/rbgfe/article/view/257964

The Intertropical Convergence Zone (ITCZ) is an important synoptic-scale system that contributes to the rainfall patterns in the northern and northeastern regions of South America (SA), thus governing the precipitation regime in the region. The variabilities and interactions of the ITCZ, seasonally with climate phenomena, cause extreme events that have impacts on various vulnerable sectors in SA. This study aims to qualitatively analyze the conditions generated by the ocean-atmosphere interactions represented by the Atlantic Meridional Mode (AMM), Southern Oscillation Index (SOI), and precipitation, with emphasis on the role of the ITCZ in the northern sector of SA. Monthly precipitation data, horizontal wind components, AMM, and SOI obtained from the National Institute of Meteorology (INMET) and the National Atmospheric Oceanic Administration (NOAA) for the period 1981 to 2018 were used. By using descriptive statistics (mean) and calculating anomalies applied to the indices and observed precipitation, respectively, it was possible to observe the seasonal variability of the ITCZ throughout the historical series, as well as the multidecadal variability of the related climate indices directly associated with precipitation anomalies for Belém - PA. The analyses indicated that the Atlantic plays an important role as a climate modulator in the northern sector. Similarly, the most intense convective activities were concentrated during the months of the austral autumn when the ITCZ shifted south of the equator with the North Atlantic Subtropical High (NASH) acting as a support for moisture advection towards the northern SA. Keywords: ZCIT, climatology, atmospheric circulation, climatic indices, rainfall regime. Tendo em vista que os extremos climáticos de precipitações pluviométricas ocasionam transtornos para diversos setores da sociedade, pesquisa-se sobre a Zona de Convergência Intertropical (ZCIT), sua interação e variabilidade sobre o norte da América do Sul. Para tanto é necessário analisar os possíveis ...