Influence of the antarctic ozone hole and atmospheric dynamics on ozone in southern Brazil
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2022-08-22Primeiro coorientador
Bencherif, Hassan
Primeiro membro da banca
Bègue, Nelson
Segundo membro da banca
Steffenel, Luiz Angelo
Terceiro membro da banca
Peres, Lucas Vaz
Quarto membro da banca
Anabor, Vagner
Quinto membro da banca
Boiaski, Nathalie Tissot
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The austral spring in the Southern Hemisphere presents temporary reductions in ozone content mainly in the Antarctic region known as the Antarctic Ozone Hole (AOH). However, studies show an influence in mid-latitude regions, such as southern Brazil, where days with temporary decreases in the total ozone column (TCO) are identified. The main objective of this thesis is to investigate this influence of AOH on the southern region of Brazil, using data from the total ozone column and vertical profiles that will help to identify the preferential height at which these decreases occur in southern Brazil, in addition to analyzing the atmospheric dynamic behavior during these events in the period 42 years of data (1979 to 2020). The methodology used comprises the analysis of average daily data of the total column of ozone through surface instruments (Brewer Spectrophotometer), satellite data (TOMS and OMI), and to compare reanalysis data from the ECMWF-ERA5, for the identification of events of influence of the AOH on the southern region of Brazil. The analysis of the vertical content of O3 data from the TIMED/SABER satellite provides daily data from 15 to 105 km in height and has 17 years of O3 profiles available in the period from 2002 to 2018. The validation of these data was necessary, and for that the SHADOZ network of ozonesondes measurements was used to carry out this validation through the tropical season in Natal/RN as a reference. This validation showed a good agreement between the two instruments, enabling the use of SABER for the analysis of AOH influence events. From this, 102 events were identified that influenced Santa Maria/RS with a temporary decrease in O3 content during the period, and with an average drop between 24 - 28.1 km in altitude. In the dynamic analysis, the stratospheric fields showed an increase in the potential vorticity in the average of the events, mainly in the months of September and October. The conceptual models in the horizontal and vertical section of the atmosphere explain the action of the stratospheric and tropospheric jet during the occurrence of events of decrease in the O3 content in Santa Maria/RS. It was possible to identify the strong influence on the development of these events through the connection of the stratospheric jet (polar vortex) with the tropospheric jets (polar and subtropical jet) at medium and high levels of the atmosphere.
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