Climatology of explosive cyclones over cyclogenetic area of South America

• Published in: Revista brasileira de meteorologia Vol. 28; no. 1; pp. 43 - 56
• Main Authors: BITENCOURT, Daniel Pires, FUENTES, Marcia Vetromilla, de Souza CARDOSO, Camila
• Format: Journal Article
• Language: English
• Published: 01.03.2013
• Subjects: ASW, South America
• ISSN: 0102-7786
• DOI: 10.1590/S0102-77862013000100005

Extratropical cyclones are defined as "explosive" when their deepening rate is maintained at 1 hPa h super(-1) during a 24-h period. Those systems are important over the South American continent due to their severe socio-economic impacts. This study presents a climatology of explosive cyclones over the cyclogenetic area of South America using NCEP-NCAR re-analysis data from 1957 to 2010. The deepening rate of an individual cyclone was classified with respect to their average latitude. Six-hourly storm attributes such as frequency, genesis, tracks, and deepening rates were analyzed. As a second step, their depth, central pressure, and radius were meaningfully compared with the climatological values obtained from non-explosive cyclones. Horizontal wind fields were compared through a co-moving coordinate system consisting of a 30[degrees] lat x 30[degrees] lon domain. It was found that the trajectory of most systems started over the ocean and that no explosive cyclones were found to occur at north of 27[degrees]S. This study also highlights that, on average, explosive cyclones are 5.1 hPa deeper, have a radius 0.41[degrees]lat. larger, and a central pressure 15.5 hPa lower than nonexplosive cyclones. In addition, the data suggested that explosive cyclones were associated with wind speeds that were on average 60 % stronger than non-explosive cyclones.