Ciclogêneses explosivas na América do Sul e no Atlântico Sul entre 2012 e 2014: estudos de casos

Abstract

The extratropical cyclones’ appearance and development (cyclogenesis) occur often throughout the year in the southern half of South America and in the South Atlantic. Such phenomenon is associated with damages to the local population, to the economy as well as with deaths due to its relation with factors such as strong winds, torrential rains and with lightning. The aim of the present study is to analyze the life cycle of eight explosive extratropical cyclones (EXCs) and to compare them with eight “ordinary” cyclones (ORCs) in order to identify differences in the dynamic and thermal forcing. The EXCs present elevated 250 hPa divergence, 500 omega vertical velocity, 850 hPa temperature advections and oceanic latent heat flux values as well as for a longer period. More extended upper- and mid-level waves in the explosive cases and in one ORC were observed. The low-level EPV anomalies were vertically wide and strong at the end of the EXCs’ deepening phase and in one ordinary case. The EXCs presented warm seclusions, which is in agreement with the literature.