Relationship between the stratospheric polar vortex and the Southern Annular Mode in the southern hemiphere and the impact on the extratropical cyclones.

• Grant number: 23/16446-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: March 01, 2024
• End date: December 31, 2024
• Field of knowledge: Physical Sciences and Mathematics - Geosciences - Meteorology
• Principal Investigator: Luiz Felippe Gozzo
• Grantee: Fernanda Peruzzo Widar
• Host Institution: Faculdade de Ciências (FC). Universidade Estadual Paulista (UNESP). Campus de Bauru. Bauru , SP, Brazil

Abstract

Although the study and monitoring of micro and mesoscale meteorological phenomena and conditions are fundamental to achieving a good weather forecast, understanding synoptic and planetary scale phenomena are just as important for forecasting. Therefore, understanding their relationships and impacts on meteorology and consequently on people's lives is of paramount importance. In this project, the objective is to analyze a climatology of the Southern Annular mode and of the stratospheric polar vortex within a period of thirty-one years (1991 to 2022), calculating an index for each phenomenon, which will be based on (Gong and Wang, 1999) and will use data on monthly averages of geopotential height at 300hPa and isentropic potential vorticity at 10hPa, respectively. Finally, the aim is to establish a statistically significant correlation between the two phenomena (using a Pearson linear correlation and the t-Student hypothesis test) and determine the impact that the interaction of these phenomena causes in extratropical cyclogenesis of the southern hemisphere, , if such impact exists. The data for calculating the indices will be obtained from the ERA5 reanalysis of the European Center for Medium-Range Weather Forecasts (ECMWF), and the extratropical cyclones climatology are from the Climatic Studies Group at the University of São Paulo (GREC-USP), who also work with the Pearson correlation method. By investigating a possible relationship and interaction between the Southern Annular Mode and the stratospheric polar vortex, we move towards a better understanding of both phenomena and their impact on the dynamics of the atmosphere and on systems that directly impact the weather and the daily lives of the population.