Influência das ligações das correntes de jato entre os hemisférios na formação de fenômenos meteorológicos adversos no Nordeste brasileiro

Abstract

Brazilian Northeast Jet Streams (BNEJS) are the main Jet Stream (JS) that influence throughout Brazilian Northeast (BNE), but their connections with adverse phenomena have not yet been studied. Adverse phenomena directly influence society with the formation of fogs and mists in the stable atmosphere and thunderstorms and heavy rain in the unstable atmosphere. These phenomena cause many damage to population, for example, affect air safety, no time of landing and aircraft take-off. Research aims were to study the influence of BNEJS connections with both Northern (NH) and Southern (SH) Hemispheres in the formation of adverse meteorological phenomena in the BNE. The study was carried out from 2017 to 2019. The data from NCEP-DOE Reanalysis 2, with a resolution of 2.5°x2.5 ° at the level of 200 hPa were used in this study. The adverse meteorological phenomena information was obtained from the REDMET database of the API application of all BNE capitals. All BNEJS were divided into three circulation patterns: Southern, Zonal and Transversal. Examples of the Southern, Zonal and Transversal events are presented in detail with the analysis of the Geopotential Height (Ag) at the level of 200 hPa. The adverse phenomena recorded were identified according to their position at the entrance (hot and cold side) and exit (hot and cold side) of the BNEJS. Connections between hemispheres were identified and quantified: the BNEJS links with other JSs types (Subtropical Jet Stream-STJS and Polar Jet Stream-PJS) were detected. BNEJS were identified every month. Connections between the hemispheres were detected mainly in the coldest months of SH during study years. Analysis of the Southern, Zonal and Transversal processes showed that Transversal processes occurred more frequently than others. The most frequent links were BNEJS + STJSSH + PJSSH, BNEJS + STJSNH + PJSNH and BNEJS without connections were also often observed. The most frequent phenomena were light rain, thunderstorm with light rain and humid mist. Adverse phenomena were more frequent in the transverse process (hot side of entrance and cold side of exit of the CJNEB. Thunderstorm occurred mainly at airports in the north of the BNE.