The Upper Tropospheric Cyclonic Vortex Influence over Moisture Convergence and Precipitation on Brazilian Northeastern

The Upper-Tropospheric Cyclonic Vortexes (UTCV) are one of the main synoptic systems responsible for rainfall production in the pre-rainy season over Northeastern Brazil (BNE). This study aims to analyze the UTCV contribution with precipitation and moisture transport convergence in the BNE, comparing it to the most important moisture recycling region in South America from 2015 to 2017 - The Amazon region (AMZ), which has the largest hydrographic basin in the world; in addition to the high importance for the moisture transport to extratropical latitudes of the continent. Furthermore, the El Niño Southern Oscillation influence on the frequency and intensity of the UTCV was also investigated. The method proposed by this study sought to calculate the average moisture convergence and precipitation through pre-established areas using virtual boxes. This comparison concerns the average intensity and total amount of moisture convergence and precipitation for the defined regions. 22 UTCV were identified during the three years of analysis, with the highest frequency in 2016, the transition year between El Niño and La Niña. Through the two boxes fixed in both study regions, it was possible to observe, on certain dates, higher concentrations of moisture convergence and precipitation in the BNE concerning AMZ. This occurred during the presence of some vortexes over the BNE, mainly in 2016, highlighting a case in January of that same year when the moisture convergence values in the BNE were more intense than the first three months in the AMZ.