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| Kounta, Lala; Capet, Xavier; Jouanno, Julien; Kolodziejczyk, Nicolas; Sow, Bamol; Gaye, Amadou Thierno. |
| The West African seaboard is one of the upwelling sectors that has received the least attention, and in situ observations relevant to its dynamics are particularly scarce. The current system in this sector is not well known and understood, e.g., in terms of seasonal variability, across-shore structure, and forcing processes. This knowledge gap is addressed in two studies that analyze the mean seasonal cycle of an eddy-permitting numerical simulation of the tropical Atlantic. Part 1 is concerned with the circulation over the West African continental slope at the southernmost reach of the Canary Current system, between similar to 8 and 20 degrees N. The focus is on the depth range most directly implicated in the wind-driven circulation (offshore and coastal... |
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| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00458/56969/58862.pdf |
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| Claudet, Joachim; Bopp, Laurent; Cheung, William W.l.; Devillers, Rodolphe; Escobar-briones, Elva; Haugan, Peter; Heymans, Johanna J.; Masson-delmotte, Valérie; Matz-lück, Nele; Miloslavich, Patricia; Mullineaux, Lauren; Visbeck, Martin; Watson, Robert; Zivian, Anna Milena; Ansorge, Isabelle; Araujo, Moacyr; Aricò, Salvatore; Bailly, Denis; Barbière, Julian; Barnerias, Cyrille; Bowler, Chris; Brun, Victor; Cazenave, Anny; Diver, Cameron; Euzen, Agathe; Gaye, Amadou Thierno; Hilmi, Nathalie; Ménard, Frédéric; Moulin, Cyril; Muñoz, Norma Patricia; Parmentier, Rémi; Pebayle, Antoine; Pörtner, Hans-otto; Osvaldina, Silva; Ricard, Patricia; Santos, Ricardo Serrão; Sicre, Marie-alexandrine; Thiébault, Stéphanie; Thiele, Torsten; Troublé, Romain; Turra, Alexander; Uku, Jacqueline; Gaill, Françoise. |
| The health of the ocean, central to human well-being, has now reached a critical point. Most fish stocks are overexploited, climate change and increased dissolved carbon dioxide are changing ocean chemistry and disrupting species throughout food webs, and the fundamental capacity of the ocean to regulate the climate has been altered. However, key technical, organizational, and conceptual scientific barriers have prevented the identification of policy levers for sustainability and transformative action. Here, we recommend key strategies to address these challenges, including (1) stronger integration of sciences and (2) ocean-observing systems, (3) improved science-policy interfaces, (4) new partnerships supported by (5) a new ocean-climate finance system,... |
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Palavras-chave: Ocean health; Human well-being; United Nations; Policy levers; Sustainability; Transformative actions; Strategy. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00637/74861/75262.pdf |
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| Diankha, Ousmane; Ba, Aliou; Brehmer, Patrice; Brochier, Timothee; Sow, Bamol Ali; Thiaw, Modou; Gaye, Amadou Thierno; Ngom, Fambaye; Demarcq, Herve. |
| We investigate Sardinella aurita and Sardinella maderensis recruitment success relative to the variability of oceanographic conditions in Senegalese waters using generalized additive models (GAM). Results show that recruitment of both species is marked by a strong intra-annual (seasonal) variation with minimum and maximum in winter and summer, respectively. Their interannual variations are synchronous until 2006 (recruitment decreasing), while from 2007 there is no synchrony. The model developed shows that sardinella recruitment variability is closely related to the tested environmental variables in the study area. However, the key environmental variables influencing the recruitment success are different for both species: the Coastal Upwelling Index and... |
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Palavras-chave: Recruitment success; Sardinella aurita; Sardinella maderensis; Upwelling; West Africa. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00611/72299/71189.pdf |
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| Senghor, Habib; Machu, Eric; Hourdin, Frederic; Gaye, Amadou Thierno. |
| The impact of desert aerosols on climate, atmospheric processes, and the environment is still debated in the scientific community. The extent of their influence remains to be determined and particularly requires a better understanding of the variability of their distribution. In this work, we studied the variability of these aerosols in western Africa using different types of satellite observations. Sea-WiFS (Sea-Viewing Wide Field-of-View Sensor) and OMI (Ozone Monitoring Instrument) data have been used to characterize the spatial distribution of mineral aerosols from their optical and physical properties over the period 2005-2010. In particular, we focused on the variability of the transition between continental western African and the eastern Atlantic... |
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| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00393/50442/69636.pdf |
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| Diankha, Ousmane; Demarcq, Herve; Fall, Massal; Thiao, Djiga; Thiaw, Modou; Sow, Bamol Ali; Gaye, Amadou Thierno; Brehmer, Patrice. |
| This study investigated variations of landings of two key species, Sardinella aurita and Sardinella maderensis, in Senegalese waters over a ten-year period (2004-2013). Using generalized additive models, it was found that fishing gear played a major role in explaining differences in monthly landings for both species (51-71% deviance explained). Its effect was more significant in the southern part of Senegal. Fishing effort (number of trips) accounted only for 4-18% of variability in landings. Purse seine (PS) fishing was the most important contributor to the landings of both species. In addition, in the southern area, surrounding gillnet fishing was also important for S. maderensis. Modeling results showed that the relationship between monthly effort and... |
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Palavras-chave: Effects of fishing; Generalized additive model; Sardinella aurita; Sardinella maderensis; Purse seine; Surrounding gillnet; Senegal. |
| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00616/72808/72585.pdf |
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