Upper Tropospheric Cyclonic Vortex Synoptic and Vertical Structure Study Occurred in January 2016

Abstract

The Upper-Tropospheric Cyclonic Vortexes (UTCV) are one of the main synoptic systems that provoke alterations in the weather during the pre-rainy season over Northeastern Brazil (BNE). The main objective of the study is to understand the UTCV configuration that was developed during 26 days in January 2016 through synoptic and thermodynamic analysis. In addition to the vortex, systems of different spatial and temporal scales such as the South Atlantic Convergence Zone (SACZ), Madden-Julian Oscillation (OMJ) were configured simultaneously, along with the El Niño that had been active since 2015. The connection between these systems caused a large increase in rainfall over the BNE. The UTCV configuration together with the SACZ being driven by the propagation of the MJO determined the excess of rainfall during the days analyzed. The western periphery of the vortex was positioned close to the BNE east coast, causing a change in the convergence pattern of large-scale moisture transport, which began to converge on the BNE, increasing precipitation rates in some states. The evaluation of the UTCV vertical structure through vertical sections indicated upward movements only in the western periphery, the eastern periphery was characterized by strong convective inhibition.

Keywords
UTCV; tropical region; SACZ; MJO