In this study an Objective Method (OM) to identify Upper-Tropospheric Cyclonic Vortex (UTCV) in South Tropical region, based on relative vorticity and on horizontal wind flow of the wind around the system center was developed. The OM was elaborated using reanalysis data of the National Center for Environmental Prediction-National Centers for Atmospheric Research (NCEP-NCAR) and validated for a period of five years (from 2002 to 2006),by through a comparison between the OM results and the ones obtained through field analyses (FA) of wind and relative vorticity. On the other hand a FA for evaluation in identifying UTCV was made in the same period through by a comparison between these results and the ones obtained using Satellite Images on water vapor channel satellite pictures. The FA presented satisfactory results and, therefore set of NCEP-NCAR reanalysis was applied to the MO. A good OM performance was observed in identifying these systems, as well as some associated characteristics, such as, number of occurrence, number of days in action, positioning, displacement direction and region formation.
upper-tropospheric cyclonic vortex; objective method; validation; South Tropical region
