Aspectos sinóticos de vórtices ciclônicos em altos níveis que provocaram precipitações externas nas cidades de Recife, Maceió e Aracaju no período de 2011 à 2015: estudo de casos

Abstract

This study aimed to characterize synoptic aspects of Upper Tropospheric Cyclonic Vortices (UTCV) cases that caused extreme rainfall in the cities of Recife, Maceió and Aracaju during the period 2011 to 2015. For analysis and understanding of the synoptic aspects of UTCV cases daily rainfall data were used satellite images, the NCEP / NCAR and radiosondes. With the data of daily rainfall, the percentiles technique was used and it was considered as an extreme rainfall event (ERE) value equal to or above the 95th percentile with the obtained value, identified the amount and variability of proceedings ERE between January 2011 and December 2015 in the study area. Was selected the ERE occurred during the season UTCV (November to March) and through satellite image analysis along with the current line fields at high levels (200 hPa) it was possible to identify how many of ERE occurred November to March were caused by UTCV. The occurrence of 6 UTCV cases was found, these cases caused: 46.6% of ERE in the city of Recife (7 of 15), 60% of ERE in Maceió (3 of 5) and 66.6% of ERE in the city of Aracaju (2 of 3). The CVHL denominated 1, 4 and 6 formed by the African Formation I mechanism and showed a tendency to be more durable and remain active from 9 to 16 days. The UTCV 2 and 3 formed by the Classic mechanism and UTCV 5 formed the Formation High mechanism. The UTCV cases of more lasting, ranging between 9 and 16 days, occurred in the months of December, January and February, and the less durable, averaging two days, occurred in the months of November and March. The field relative vorticity proved an excellent mechanism to provide, in time scales, both the onset and the mangling of UTCV.