Cyclones and Atmosferic Circulation Patterns Study in the South Atlantic Ocean Near the Coast of South and a Southest of Brazil Using Reanalysis Era-Interim Data

Abstract

The main objective of this research is to study the cyclones, and the atmospheric circulation pattern associated with them, occurring in South Atlantic Ocean, using data from ERA-Interim Reanalysis from October to April in the 2003-2013 period. An objective method was developed and applied to identify the dates, location and intensity of cyclones, which allowed to generate composites of some meteorological variables. The results showed that, on average, 17 cases of cyclones occurred in the months from October to April and the life within the studied area reaches up to 8 days. The period of October/2008 to April /2009 calls attention for recording 27 cases. Composites for the entire period showed a combination of the difluence in the flow at upper levels, associated with an mid-tropospheric trough and the presence of positive zonal-wind anomalies are favorable to formation of cyclone in the Atlantic Ocean near South and Southeastern Brazil. Convergence of low-level flow were decisive to stimulate cyclogenesis in the region. The case studied showed an application of the developed tool that can be useful in improving the numerical prediction models of this type of weather system.

Keywords:
cyclones; cyclogenesis in the South Atlantic Ocean; Era-Interim reanalysis