Atuação da corrente de jato do Nordeste brasileiro associada a diferentes sistemas sinóticos

Abstract

The economy of the Northeast region, based on agriculture, livestock, and tourism, is sensitive to weather variations. The research focuses on the influence of the Brazilian Northeast Jet Stream (BNEJS) and other synoptic systems on the region's meteorological conditions. Recently, BNEJS has been identified as a significant factor in local heavy rainfall, as its vertical movements interact with other meteorological systems. The study aims to examine the vertical structure of BNEJS in conjunction with the South Atlantic Subtropical High (SASH), Cold Front (CF), Frontal Boundaries (FB), Bolivian High (BH), and Upper Tropospheric Cyclonic Vortex (UTCV), with a focus on the implications of these interactions on the formation of adverse weather phenomena. The data cover the period from 2016 to 2018. Synoptic and thermodynamic analyses were based on the following data: a) METAR coding containing surface data obtained by the Department of Airspace Control (DECEA), b) GIBBS satellite images in the infrared (IR) channel, provided by NOAA, and GOES + METEOSAT-10 and GOES 16 satellite images in the IR channel, provided by CPTEC, c) Reanalysis data from the ERA5 numerical model (0.25°×0.25°, vertically distributed at standard pressure levels and at synoptic times of 00, 06, 12, and 18 UTC), provided by ECMWF. The GrADS software was used for composing meteorological fields and simulated vertical profiles. BNEJS was observed on 1087 days (99%), with an average speed of 35 m/s. SASH was present on 991 days, Frontal Extremities (FEs) on 93 days, and UTCV and BH acted together with BNEJS on 380 days. Five exemplary cases illustrate the influence of BNEJS in different synoptic scenarios. In the first case (10/01/2016), the interaction of BNEJS with BH, UTCV, and SASH resulted in lifting that caused precipitation on the Brazilian Northeast (BNE) coastal zone. In the second case (23/01/2018), BNEJS influenced thunderstorms, heavy rainfall, and fog in Maceió in interacting with UTCV and BH, altering the UTCV pattern. The third case (14/11/2017) showed how BNEJS intensified lifting in the FE activity zone. The fourth case (16/07/2017) illustrates the interaction between BNEJS, SASH, BH, and an upper-level trough, affecting the vertical movements of the region. In the fifth case (22/08/2018), BNEJS was absent, and SASH was the main active system, without intense vertical movements and precipitation. Furthermore, the BNEJS- influenced region occurred 748 precipitation days and 21 fog events in Campina Grande (SBKG) during the study period. This study deepens the understanding of the influence of BNEJS and other synoptic systems on the meteorological conditions in Alagoas, providing valuable information for the prediction of adverse meteorological events in the region.