A minor Ivorian-Ghanian upwelling season influenced by the interaction between the Atlantic El Niño and marine heat waves
Paper Details
A minor Ivorian-Ghanian upwelling season influenced by the interaction between the Atlantic El Niño and marine heat waves
Abstract
This study examines the spatio-temporal variability of coastal upwelling in the northern Gulf of Guinea during the minor upwelling season (January–February) between 1993 and 2025, and analyses its relationship with the Atlantic El Niño phenomenon and marine heatwaves. Sea surface temperature data reveal two distinct upwelling centres (Cape Palmas and Cape Three Points). The western cell exhibits high interannual variability, with an extreme event in 1996, but no significant trend. In contrast, the eastern cell shows a significant downward trend, with a regime shift between 2006 and 2007. Analysis of marine heatwaves shows that they are almost exclusively concentrated after 2017, with a record intensity in 2024 (33.9 °C d). Their cumulative intensity is associated with a significant upward trend (slope= +0.2965 °C d/year). Bivariate analyses of the Atlantic El Niño phenomenon, marine heatwaves and the deep-water upwelling area reveal significant negative correlations. However, a multiple regression identifies the Atlantic El Niño as the main factor reducing upwelling, whilst the direct effect of marine heatwaves is not significant. These results highlight contrasting trends within upwelling cells, the recent emergence of intense marine heatwaves, and the dominant role of the Atlantic Niño in modulating the intensity of upwelling in the region.
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Mamadou Koné*, Hilaire Amemou, Kouakou Urbain Koffi, Yves Kouadio, 2026. A minor Ivorian-Ghanian upwelling season influenced by the interaction between the Atlantic El Niño and marine heat waves. J. Biodiv. Environ. Sci., 29(2), 53-66.
Copyright © 2026 by the Authors. This article is an open access article and distributed under the terms and conditions of the Creative Commons Attribution 4.0 (CC BY 4.0) license.