Abstract
The weather systems that cause storms accompanied by strong winds, such as cold fronts and extratropical and subtropical cyclones, often interfere with the sea condition. As a consequence, sea levels can rise dramatically causing coastal flooding. The 2015 and 2016 years were characterized by the occurrence of the positive phase of the phenomenon El Niño - Southern Oscillation, with very strong intensity. The Southern Brazil presented greater conditions of atmospheric instability, with frequent passages of frontal systems and formation of extratropical cyclones, interfering in the sea conditions. In view of the above, this study aimed to evaluate the atmospheric conditions during rough sea events in the South and Southeast of Brazil during 2015/2016 El Niño, through information presented in the Warnings of Bad Weather, issued by the Hydrographic Center of the Brazilian Navy. Through these warnings and ERA-Interim reanalysis data, we analyzed the distributions by sea area, by month and by season of the year, as well as the analysis of synoptic fields plotted on the surface for the 12 most prominent events. As a result, the autumn and winter months recorded the highest occurrences of rough sea in both areas during the 2015/2016 El Niño. In general, four atmospheric patterns favorable to rough sea events were identified, due to the action of extratropical cyclones and the performance of post-frontal high pressure systems.
Keywords:
El Niño; rough sea; atmospheric systems
