• Energy Research

This study assessed the extremes of wave conditions for past (1979–2005) and future (2026–2045 and 2081–2100) time slices in the Gulf of Guinea (GoG). The ensemble produced from eight General Circulation Models under different Representative Concentration Pathway (RCP) emission scenarios (RCP4.5 and RCP8.5) was subjected to linear regression analysis and Mann–Kendal test for their trends and significance, respectively. Results showed an increase in the extreme of significant wave height (Hs) and mean wave period (Tm) between 1979–2005, 2026–2045, and 2081–2100 with few exceptions. The average values of annual and seasonal Hs and Tm range from 1.26–1.62 m and 10.37 s–10.86 s, respectively, for 1979–2005. These Hs values are projected to increase by 0.1 m (0.05 m) to 1.72 m (1.67 m) and the Tm will increase by 0.29 s (0.24 s) to 11.15 s (11.10 s) by the end of the century (mid-century) time slices, respectively. The mean wave direction (Dm) (201.89°–206.27°) showed an anticlockwise shift (−29.2 × 10−3 degrees per year) for 1979–2005 which is projected to become more southwesterly with an increase up to 2.2° (0.5°) by end (mid) century in 2100 (2045), respectively. Future work will be on the impacts of changing wave on longshore sediment transport along the GoG.

Affichage des formules : ?Les formules mathématiques ont été codées en MathML et sont affichées dans cette version HTML à l'aide de MathJax afin d'améliorer leur affichage. Décochez la case pour désactiver MathJax. Cette fonctionnalité nécessite Javascript. Cliquez sur une formule pour zoomer. Visualización de fórmulas: Las fórmulas matemáticas se han codificado como MathML y se muestran en esta versión HTML utilizando MathJax para mejorar su visualización. Desmarque la casilla para desactivar MathJax. Esta función requiere Javascript. Haz clic en una fórmula para hacer zoom. Formulae display:?Mathematical formulae have been encoded as MathML and are displayed in this HTML version using MathJax in order to improve their display. Uncheck the box to turn MathJax off. This feature requires Javascript. Click on a formula to zoom. عرض الصيغ:? تم ترميز الصيغ الرياضية كـ MathML ويتم عرضها في إصدار HTML هذا باستخدام MathJax لتحسين عرضها. قم بإلغاء تحديد المربع لإيقاف تشغيل MathJax. تتطلب هذه الميزة جافا سكريبت. انقر على صيغة للتكبير/التصغير.

This study examined the carbon cycling dynamics in the tropical Atlantic Ocean from 1985 to 2023, focusing on factors influencing the surface partial pressure of CO2 (pCO2), freshwater input, total alkalinity (ALK), total dissolved carbon (TCO2), and pH levels. The time series data revealed significant trends, with average pCO2 concentrations rising from approximately 350 μatm in the early 1990s to over 400 μatm by 2023. The TCO2 levels increased from about 2000 μmol/kg to 2200 μmol/kg, while ALK rose from approximately 2300 μmol/kg to 2500 μmol/kg. This increase highlights the ocean’s role as a carbon sink, particularly in areas with high biological productivity and upwelling where TCO2 also rose. This study employed Empirical Orthogonal Functions (EOFs) to identify variability modes and understand spatial patterns of pCO2. Freshwater dynamics significantly affect TCO2 concentrations, particularly in coastal regions, where pH can shift from 8.2 to 7.9, exacerbating acidification. Rising sea surface temperatures have been linked to elevated pCO2 values. These findings support the need for ongoing monitoring and effective management strategies to mitigate the impacts of climate change and ensure the sustainability of marine resources. This study documented the long-term trends in tropical Atlantic CO2 parameters linked to the North Atlantic Oscillation (NAO) and Atlantic Multidecadal Oscillation (AMO).

This study applied ocean models data from Copernicus Marine Environment Monitoring Service (CMEMS) in assessing the impacts of the trends in key ocean parameters on the primary production of the Gulf of Guinea (GoG). Trend analyses, from 1993 to 2020, were done using linear regression and Mann-Kendall significance test methods to ascertain inter-annual and inter-seasonal variations and check the significance of the trends, respectively. Results affirm that temperature, salinity, nutrients, and oxygen play significant roles in the primary production of the GoG. Also, parameters such as temperature, salinity, chlorophyll-A, net primary production, phosphate, and dissolved oxygen have been experiencing increases between the study duration while silicate and nitrate have been declining in the GoG. However, there are regions and years with contrary values to the average trends. The varying level of significance of the trend showed that the impacts of the climate on the primary production of the GoG vary basin-wide.

This study investigated the historical and future wave power potential in the Gulf of Guinea (GoG) with the aim of identifying high-density wave energy locations for potential exploitation. To estimate wave power density (WPD) for three time periods (past: 1979–2005, mid-century: 2026–2050, and end-century: 2081–2100), we utilized significant wave height and mean wave period obtained from eight General Circulation Models. Using an ensemble of these WAVEWATCH III simulated datasets, we calculated WPD and assessed overall and seasonal trends, projecting changes under Representative Concentration Pathway (RCP) 4.5 and 8.5 scenarios. Results revealed higher potential WPD in the western GoG, particularly near the coast, with increased values offshore. Spatially, WPD change rates varied widely (−0.021 to 0.039 kW/m per year), suggesting both positive and negative trends, though generally low. Projections indicated a potential increase from 0.5 to 1.0 kW/m by the end of the century. The estimated potential power for harvesting exceeded 14,000 MW, with offshore regions showing better wave converter performance. This study concludes that GoG's wave energy is a promising renewable resource, offering a potential solution to future power needs and contributing to regional greenhouse gas emission mitigation.