Análise do indice de anomalia de chuva (IAC) e a influência do fenômeno el niño - oscilação sul (ENOS) na floresta Nacional de Caxiuanã

Abstract

Climate change is increasingly important in the natural processes of the Amazon. Thus, understanding the quantity, intensity, and spatial distribution of rainfall contributes to the management and territorial planning of the area. One way to study the rainfall of a specific region is through the Rainfall Anomaly Index (RAI). This study aims to analyse the variability of annual precipitation in the Caxiuanã National Forest, highlighting the years of occurrence of El Niño Southern Oscillation (ENSO) phenomena. The data were obtained from the LBA and ESECAFLOR projects located at the Ferreira Pena Scientific Station, covering a period of 43 years. RAI calculations were based on monthly averages and the averages of the 10 years with the highest and lowest precipitation. During extreme El Niño events, the dry period in the region was drier, while during moderate La Niña events, the rainy period varied differently than normal. Using the RAI, it was possible to visualize and analyse the influence of the ENOS, confirming that the index is compatible with the Pacific Decadal Oscillation (PDO) when analysing the precipitation variation in the region.