Mean sea level, tidal components and surges in Guanabara Bay (Rio de Janeiro) from 1990 to 2021

• Published in: International journal of climatology 2024-11, Vol.44 (13), p.4629-4648
• Main Authors: Tecchio, Rodrigo, Souza, Danilo Couto, Silva, Matheus Bonjour Laviola, Oliveria Costa, Marcia Carolina, Camargo, Ricardo, Harari, Joseph
• Format: Article
• Language: English
• Subjects: Altimeters; Anticyclones; Atmospheric evolution; Climate models; Climate prediction; Climatic analysis; Coastal zone; Components; Ekman transport; Evolution; Mean sea level; Metropolitan areas; Oceans; ocean–atmosphere interaction; PACMARE; Pattern analysis; Pressure; Satellite altimetry; Satellite observation; Sea level; Sea level changes; Sea level fluctuations; Seasonal variability; Seasonal variation; Seasonal variations; Southern Hemisphere; Surges; synoptic patterns; tidal analysis; Urban areas; Wind; Winds
• ISSN: 0899-8418; 1097-0088
• DOI: 10.1002/joc.8600

Guanabara Bay, located in the Metropolitan Region of Rio de Janeiro, one of the largest urban coastal areas in the Southern Hemisphere, is subject to intense maritime traffic due to the presence of several ports. These facilities are affected by sea level fluctuations, influenced by atmospheric and astronomical forces, which motivates synoptic and climatological analysis, including meteorological and astronomical tidal phenomena. This study aimed to assess the evolution of tidal components and the relative mean sea level (MSL) between 1990 and 2021, as well as the atmospheric influence on extreme meteorological tide events, in which the MSL exceeded ±2 and ±3 (±29.98 and ±44.97 cm) standard deviations. The results have shown that, albeit small, the main tidal components (M2, S2, O1, M4, Q1, K1, K2 and N2) indicated positive trends in the increase of amplitude and phase, despite the small quantities. For the relative MSL, an increase of 0.30 cm·year−1 was observed in agreement with estimates from global series from satellite altimeters and climate model predictions. Pressure and wind field analyses led to the identification of seasonal variability and the pattern of evolution of atmospheric systems associated with extreme events. In the case of positive surges, very intense winds from the SW, extending along the S/SE Brazilian coast, are caused by the presence of a high‐pressure centre over the continent and low‐pressure centres over the ocean, leading to water piling up. In turn, negative surges are caused by the presence of an anticyclone over the ocean, generating NE winds parallel to the coast of Rio de Janeiro, inducing Ekman transport and lowering the sea level. Therefore, the extreme sea level events in the Guanabara Bay are not triggered by local forces, but rather depend on the temporal persistence and direction of winds along the S/SE Brazilian coast. This study examines Guanabara Bay, Rio de Janeiro, from 1990 to 2021, revealing significant shifts in tidal patterns and mean sea level due to climate change and human impact. It highlights how atmospheric conditions influence extreme sea level events, underscoring the bay's vulnerability to global environmental trends.