Synoptic and climatological analysis of subtropical cyclone IBA

Abstract

This work proposes a case study of an unusual subtropical cyclone (Iba), registered in March 2019 over the South Atlantic Ocean near the coast of Espirito Santo and Bahia (Brazil). The main goal is to present a synoptic analysis of the cyclone, in order to characterize its subtropical structure, determine its main characteristics and identify the synoptic pattern in which it developed. Also, climatological anomalies of meteorological variables will be calculated for the month of March 2019, to investigate large-scale low frequency characteristics that may have contributed to the cyclone development. The analyses will be carried out using the European Centre for Medium-Range Weather Forecast (ECMWF) ERA5 reanalysis. The data will cover the surface up to 100 hPa, and it will have temporal resolution of 3 hours for the synoptic analysis and a month for the climatological analysis, spanning the period from 1979 to 2020. Synoptic analysis will be evaluated for genesis, mature stage and decaying stage of the cyclone. Monthly anomalies of horizontal wind and sea surface temperature during March 2019 will help to understand possible important departures from the mean March climatology that may have led to the cyclone development. It is expected that this work will contribute to the understanding and predictability of such cyclones over the South Atlantic. (AU)