Atmospheric Teleconnections and their impact on precipitation patterns in the Brazilian legal Amazon: insights from the standardized precipitation index (SPI)

The Brazilian Legal Amazon (BLA) region plays a crucial role in global climate regulation. This study investigates the impacts of atmospheric teleconnections, including the Atlantic Multidecadal Oscillation (AMO), Pacific Decadal Oscillation (PDO), Southern Oscillation Index (SOI), North Atlantic Oscillation (NAO), North Atlantic Sea Surface Temperature (TNA), and South Atlantic Sea Surface Temperature (TSA), through the Standardized Precipitation Index (SPI) at different temporal scales in the BLA. Monthly precipitation data from 1,675 grid points, covering the period from 1970 to 2019, were analyzed using the Global Precipitation Climatology Centre (GPCC) dataset. Pearson's linear correlation coefficient was employed to quantify the strength and direction of linear relationships between atmospheric teleconnections and SPI, and wavelet coherence analysis examined relationships between atmospheric teleconnections and SPI across various temporal scales. Key findings indicate that positive phases of the AMO and PDO tend to be associated with drier conditions in the BLA, while negative SOI phases, indicative of El Nino, also contribute to severe drought events. Dominant periodicities identified through wavelet coherence analysis reveal significant oscillations at 2-4 years and 8-16 years, strongly correlating with the SOI and PDO phases. Additionally, positive TNA phases are associated with increased precipitation, while positive TSA phases show a weaker correlation with precipitation variability. The regions most affected by droughts include the northern and eastern parts of the Amazon, which experience severe, prolonged drought. The results of this study advance understanding of mechanisms controlling climate variability in the Amazon, providing valuable insights for the scientific community and policymakers. Add the most important numerical results of correlation and periodicities.