Impact of ENSO on Variability of the Total Ozone Column Over the Northeast Region of Brazil - Part 1: El Niño Canonical and Modoki

Abstract The objective of this work is to analyze the annual variation and the effects of the atmospheric variability mode El Niño (Canonical and Modoki) on the concentration of the Total Ozone Column (TOC) on the NEB between 1997 and 2018 using data generated by the sensors Total Ozone Mapping Spectrometer (TOMS) and Ozone Monitoring Instrument (OMI). An average monthly variation was observed, with typical behavior of the annual cycle domain in the seasonal variability, presenting a minimum value in May and maximum in October. There was a declining trend in the series of average values for the entire area. Cluster analysis revealed that different regions of the study area have slightly different behaviors and mean values of the total ozone column. Wavelet analysis was used, which exposed cycles of twelve months in length throughout the studied area, six-month cycles, demonstrating that the semi-annual cycle dominates seasonal variability in lower latitudes, and also two to three years cycles, representing the important performance of the Quasi-Biennial Oscillation (QBO). Anomaly averages show that El Niño events affect TOC causing predominantly a decrease in their values. These Modoki events have a greater potential to affect TOC variations than canonical events, with negative anomalies of greater intensity.