Avaliação do impacto dos modos de variabilidade el niño-oscilação sul e modo anular sul nas concentrações de ozônio sobre o Hemisfério Sul

Abstract

Ozone is a gas present in the Earth's atmosphere in small quantities and that contributes significantly to the energy balance of the atmosphere. Several factors can affect its concentration and distribution, such as the variability modes El Niño - Southern Oscillation (ENSO) and Southern Annular Mode (SAM). In this study, climatological analyzes were performed for periods of ENSO and SAM using a robust series of Total Column Ozone (TOC) data from the Multi-sensor reanalysis (MSR) product, available by the European Center for Medium-Range Weather Forecasts (ECMWF), for the Southern Hemisphere area, covering a period of 41 years (1980-2020). TOC’s means, anomalies for periods with action of the variability modes and statistical analysis of the dominant variability patterns were obtained. When there is El Niño action, the accentuated transport of the Brewer-Dobson Circulation (CBD) causes positive anomalies in medium and high latitudes and negative anomalies in low latitudes. During La Niña the reverse is observed. For the action of the positive phase of the SAM, a predominance of negative anomalies is observed in high and medium latitudes, and positive in low latitudes. The inverse is observed for the negative phase. Statistical analyzes of Empirical Orthogonal Functions (EOF) show that the patterns of greatest influence on CTO during the austral summer, autumn and spring are SAM and ozone transport by CBD. The polar vortex and the ozone “croissant” are the dominant patterns in the austral spring. There is na increase in the frequency of SAM in the positive phase and an increase in the average concentrations of the CTO within the polar vortex in the spring months, effects that may be linked to climate change that alters atmospheric patterns, resulting from anthropogenic emissions of greenhouse gases, which have occurred within the study period.