{"id":2086,"date":"2021-01-12T16:23:53","date_gmt":"2021-01-12T16:23:53","guid":{"rendered":"https:\/\/www.africa-press.com\/niger\/?p=2086"},"modified":"2021-01-12T16:23:53","modified_gmt":"2021-01-12T16:23:53","slug":"quelle-est-linfluence-du-fleuve-niger-sur-lupwelling-du-golfe-de-guinee","status":"publish","type":"post","link":"https:\/\/www.africa-press.net\/niger\/toutes-les-actualites\/quelle-est-linfluence-du-fleuve-niger-sur-lupwelling-du-golfe-de-guinee","title":{"rendered":"Quelle est l\u2019influence du fleuve Niger sur l\u2019upwelling du golfe de Guin\u00e9e ?"},"content":{"rendered":"

Africa-Press<\/a> – Niger<\/a>.\u00a0<\/strong><\/span>En \u00e9t\u00e9 en face du Ghana, le vent de sud-ouest souffle parall\u00e8lement \u00e0 la c\u00f4te et se combine avec la force de Coriolis pour transporter les eaux oc\u00e9aniques de surface vers le large (divergence d’Ekman). Cela induit des remont\u00e9es d’eaux profondes, froides et sal\u00e9es et donc denses: c’est l’upwelling c\u00f4tier du golfe de Guin\u00e9e, l’un des objets d’\u00e9tude du projet Triatlas.<\/p>\n

Plus \u00e0 l’est, l’upwelling fait place aux eaux chaudes et peu sal\u00e9es, et donc moins denses, du panache du fleuve Niger. Comme la hauteur de la colonne liquide d’un thermom\u00e8tre augmente avec la temp\u00e9rature, le niveau de la mer s’\u00e9l\u00e8ve vers l’est avec ces variations de densit\u00e9. Combin\u00e9e \u00e0 la force de Coriolis, cette pente cr\u00e9e des courants dirig\u00e9s vers la c\u00f4te (convergence g\u00e9ostrophique), observ\u00e9s par satellite et reproduits dans une simulation \u00e0 haute r\u00e9solution horizontale (1\/12\u00b0) r\u00e9alis\u00e9e par les chercheurs \u00e0 l’aide du mod\u00e8le oc\u00e9anique NEMO.<\/p>\n

Pour clarifier le r\u00f4le du panache du fleuve Niger sur cette convergence g\u00e9ostrophique, les chercheurs ont supprim\u00e9 le flux d’eau douce du fleuve Niger dans une seconde simulation. D’apr\u00e8s leurs analyses, le fleuve modifie trop peu les courants, et sur une couche trop fine, pour contribuer significativement \u00e0 la convergence g\u00e9ostrophique. Le calcul d’indices d’upwelling montre que cette convergence r\u00e9duit de 50 % l’upwelling \u00e0 l’est du Ghana et sugg\u00e8re qu’elle est en fait probablement due au brusque renflement de la c\u00f4te associ\u00e9 au delta du fleuve qui, en changeant l’angle entre le vent et la c\u00f4te, freine la divergence d’Ekman et renforce ainsi le front de densit\u00e9 \u00e0 l’extr\u00e9mit\u00e9 orientale de l’upwelling et la convergence g\u00e9ostrophique qui lui est associ\u00e9e.<\/p>\n

La d\u00e9couverte de cet effet topographique reste \u00e0 approfondir et son r\u00f4le potentiel dans d’autres r\u00e9gions d’upwelling \u00e0 \u00e9valuer. Le fleuve, m\u00eame s’il n’affecte pas l’upwelling, r\u00e9chauffe tout de m\u00eame les eaux c\u00f4ti\u00e8res de plus de 1\u00b0C par des processus de surface. De tels effets locaux li\u00e9s \u00e0 la topographie c\u00f4ti\u00e8re et aux fleuves devront \u00eatre pris en compte dans les \u00e9tudes portant sur l’\u00e9volution, li\u00e9e au changement climatique, des upwellings et de leur productivit\u00e9 biologique.<\/p>\n","protected":false},"excerpt":{"rendered":"

Africa-Press – Niger.\u00a0En \u00e9t\u00e9 en face du Ghana, le vent de sud-ouest souffle parall\u00e8lement \u00e0 la c\u00f4te et se combine avec la force de Coriolis pour transporter les eaux oc\u00e9aniques de surface vers le large (divergence d’Ekman). Cela induit des remont\u00e9es d’eaux profondes, froides et sal\u00e9es et donc denses: c’est l’upwelling c\u00f4tier du golfe de […]<\/p>\n","protected":false},"author":82,"featured_media":2096,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[21,11,10],"tags":[],"class_list":["post-2086","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-communaute","category-homepage-french","category-toutes-les-actualites"],"yoast_head":"\nQuelle est l\u2019influence du fleuve Niger sur l\u2019upwelling du golfe de Guin\u00e9e ? - niger<\/title>\n<meta name=\"description\" content=\"Africa-Press - Niger.\u00a0En \u00e9t\u00e9 en face du Ghana, le vent de sud-ouest souffle parall\u00e8lement \u00e0 la c\u00f4te et se combine\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.africa-press.net\/niger\/toutes-les-actualites\/quelle-est-linfluence-du-fleuve-niger-sur-lupwelling-du-golfe-de-guinee\" \/>\n<meta property=\"og:locale\" content=\"fr_FR\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Quelle est l\u2019influence du fleuve Niger sur l\u2019upwelling du golfe de Guin\u00e9e ?\" \/>\n<meta property=\"og:description\" content=\"Africa-Press - Niger.\u00a0En \u00e9t\u00e9 en face du Ghana, le vent de sud-ouest souffle parall\u00e8lement \u00e0 la c\u00f4te et se combine\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.africa-press.net\/niger\/toutes-les-actualites\/quelle-est-linfluence-du-fleuve-niger-sur-lupwelling-du-golfe-de-guinee\" \/>\n<meta property=\"og:site_name\" content=\"niger\" \/>\n<meta property=\"article:published_time\" content=\"2021-01-12T16:23:53+00:00\" \/>\n<meta property=\"og:image\" content=\"https:\/\/static.africa-press.net\/niger\/sites\/40\/2021\/01\/39.jpg\" \/>\n\t<meta property=\"og:image:width\" content=\"720\" \/>\n\t<meta property=\"og:image:height\" content=\"405\" \/>\n\t<meta property=\"og:image:type\" content=\"image\/jpeg\" \/>\n<meta name=\"author\" content=\"cfeditorfr\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"\u00c9crit par\" \/>\n\t<meta name=\"twitter:data1\" content=\"cfeditorfr\" \/>\n\t<meta name=\"twitter:label2\" content=\"Dur\u00e9e de lecture estim\u00e9e\" \/>\n\t<meta name=\"twitter:data2\" content=\"2 minutes\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\/\/schema.org\",\"@graph\":[{\"@type\":\"Article\",\"@id\":\"https:\/\/www.africa-press.net\/niger\/toutes-les-actualites\/quelle-est-linfluence-du-fleuve-niger-sur-lupwelling-du-golfe-de-guinee#article\",\"isPartOf\":{\"@id\":\"https:\/\/www.africa-press.net\/niger\/toutes-les-actualites\/quelle-est-linfluence-du-fleuve-niger-sur-lupwelling-du-golfe-de-guinee\"},\"author\":{\"name\":\"cfeditorfr\",\"@id\":\"https:\/\/www.africa-press.net\/niger\/#\/schema\/person\/2b1cf3cd81a31e3cd26889ca66d677f1\"},\"headline\":\"Quelle est l\u2019influence du fleuve Niger sur l\u2019upwelling du golfe de Guin\u00e9e ?\",\"datePublished\":\"2021-01-12T16:23:53+00:00\",\"mainEntityOfPage\":{\"@id\":\"https:\/\/www.africa-press.net\/niger\/toutes-les-actualites\/quelle-est-linfluence-du-fleuve-niger-sur-lupwelling-du-golfe-de-guinee\"},\"wordCount\":423,\"commentCount\":0,\"image\":{\"@id\":\"https:\/\/www.africa-press.net\/niger\/toutes-les-actualites\/quelle-est-linfluence-du-fleuve-niger-sur-lupwelling-du-golfe-de-guinee#primaryimage\"},\"thumbnailUrl\":\"https:\/\/static.africa-press.net\/niger\/sites\/40\/2021\/01\/39.jpg\",\"articleSection\":[\"Communaut\u00e9\",\"homepage-french\",\"Toutes les actualit\u00e9s\"],\"inLanguage\":\"fr-FR\",\"potentialAction\":[{\"@type\":\"CommentAction\",\"name\":\"Comment\",\"target\":[\"https:\/\/www.africa-press.net\/niger\/toutes-les-actualites\/quelle-est-linfluence-du-fleuve-niger-sur-lupwelling-du-golfe-de-guinee#respond\"]}]},{\"@type\":\"WebPage\",\"@id\":\"https:\/\/www.africa-press.net\/niger\/toutes-les-actualites\/quelle-est-linfluence-du-fleuve-niger-sur-lupwelling-du-golfe-de-guinee\",\"url\":\"https:\/\/www.africa-press.net\/niger\/toutes-les-actualites\/quelle-est-linfluence-du-fleuve-niger-sur-lupwelling-du-golfe-de-guinee\",\"name\":\"Quelle est l\u2019influence du fleuve Niger sur l\u2019upwelling du golfe de Guin\u00e9e ? - niger\",\"isPartOf\":{\"@id\":\"https:\/\/www.africa-press.net\/niger\/#website\"},\"primaryImageOfPage\":{\"@id\":\"https:\/\/www.africa-press.net\/niger\/toutes-les-actualites\/quelle-est-linfluence-du-fleuve-niger-sur-lupwelling-du-golfe-de-guinee#primaryimage\"},\"image\":{\"@id\":\"https:\/\/www.africa-press.net\/niger\/toutes-les-actualites\/quelle-est-linfluence-du-fleuve-niger-sur-lupwelling-du-golfe-de-guinee#primaryimage\"},\"thumbnailUrl\":\"https:\/\/static.africa-press.net\/niger\/sites\/40\/2021\/01\/39.jpg\",\"datePublished\":\"2021-01-12T16:23:53+00:00\",\"author\":{\"@id\":\"https:\/\/www.africa-press.net\/niger\/#\/schema\/person\/2b1cf3cd81a31e3cd26889ca66d677f1\"},\"description\":\"Africa-Press - Niger.\u00a0En \u00e9t\u00e9 en face du Ghana, le vent de sud-ouest souffle parall\u00e8lement \u00e0 la c\u00f4te et se combine\",\"breadcrumb\":{\"@id\":\"https:\/\/www.africa-press.net\/niger\/toutes-les-actualites\/quelle-est-linfluence-du-fleuve-niger-sur-lupwelling-du-golfe-de-guinee#breadcrumb\"},\"inLanguage\":\"fr-FR\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\/\/www.africa-press.net\/niger\/toutes-les-actualites\/quelle-est-linfluence-du-fleuve-niger-sur-lupwelling-du-golfe-de-guinee\"]}]},{\"@type\":\"ImageObject\",\"inLanguage\":\"fr-FR\",\"@id\":\"https:\/\/www.africa-press.net\/niger\/toutes-les-actualites\/quelle-est-linfluence-du-fleuve-niger-sur-lupwelling-du-golfe-de-guinee#primaryimage\",\"url\":\"https:\/\/static.africa-press.net\/niger\/sites\/40\/2021\/01\/39.jpg\",\"contentUrl\":\"https:\/\/static.africa-press.net\/niger\/sites\/40\/2021\/01\/39.jpg\",\"width\":720,\"height\":405},{\"@type\":\"BreadcrumbList\",\"@id\":\"https:\/\/www.africa-press.net\/niger\/toutes-les-actualites\/quelle-est-linfluence-du-fleuve-niger-sur-lupwelling-du-golfe-de-guinee#breadcrumb\",\"itemListElement\":[{\"@type\":\"ListItem\",\"position\":1,\"name\":\"Accueil\",\"item\":\"https:\/\/www.africa-press.net\/niger\/\"},{\"@type\":\"ListItem\",\"position\":2,\"name\":\"Quelle est l\u2019influence du fleuve Niger sur l\u2019upwelling du golfe de Guin\u00e9e ?\"}]},{\"@type\":\"WebSite\",\"@id\":\"https:\/\/www.africa-press.net\/niger\/#website\",\"url\":\"https:\/\/www.africa-press.net\/niger\/\",\"name\":\"niger\",\"description\":\"Just another Africa News Agency Sites site\",\"potentialAction\":[{\"@type\":\"SearchAction\",\"target\":{\"@type\":\"EntryPoint\",\"urlTemplate\":\"https:\/\/www.africa-press.net\/niger\/?s={search_term_string}\"},\"query-input\":{\"@type\":\"PropertyValueSpecification\",\"valueRequired\":true,\"valueName\":\"search_term_string\"}}],\"inLanguage\":\"fr-FR\"},{\"@type\":\"Person\",\"@id\":\"https:\/\/www.africa-press.net\/niger\/#\/schema\/person\/2b1cf3cd81a31e3cd26889ca66d677f1\",\"name\":\"cfeditorfr\"}]}<\/script>\n<!-- \/ Yoast SEO Premium plugin. -->","yoast_head_json":{"title":"Quelle est l\u2019influence du fleuve Niger sur l\u2019upwelling du golfe de Guin\u00e9e ? - niger","description":"Africa-Press - Niger.\u00a0En \u00e9t\u00e9 en face du Ghana, le vent de sud-ouest souffle parall\u00e8lement \u00e0 la c\u00f4te et se combine","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/www.africa-press.net\/niger\/toutes-les-actualites\/quelle-est-linfluence-du-fleuve-niger-sur-lupwelling-du-golfe-de-guinee","og_locale":"fr_FR","og_type":"article","og_title":"Quelle est l\u2019influence du fleuve Niger sur l\u2019upwelling du golfe de Guin\u00e9e ?","og_description":"Africa-Press - Niger.\u00a0En \u00e9t\u00e9 en face du Ghana, le vent de sud-ouest souffle parall\u00e8lement \u00e0 la c\u00f4te et se combine","og_url":"https:\/\/www.africa-press.net\/niger\/toutes-les-actualites\/quelle-est-linfluence-du-fleuve-niger-sur-lupwelling-du-golfe-de-guinee","og_site_name":"niger","article_published_time":"2021-01-12T16:23:53+00:00","og_image":[{"width":720,"height":405,"url":"https:\/\/static.africa-press.net\/niger\/sites\/40\/2021\/01\/39.jpg","type":"image\/jpeg"}],"author":"cfeditorfr","twitter_card":"summary_large_image","twitter_misc":{"\u00c9crit par":"cfeditorfr","Dur\u00e9e de lecture estim\u00e9e":"2 minutes"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"Article","@id":"https:\/\/www.africa-press.net\/niger\/toutes-les-actualites\/quelle-est-linfluence-du-fleuve-niger-sur-lupwelling-du-golfe-de-guinee#article","isPartOf":{"@id":"https:\/\/www.africa-press.net\/niger\/toutes-les-actualites\/quelle-est-linfluence-du-fleuve-niger-sur-lupwelling-du-golfe-de-guinee"},"author":{"name":"cfeditorfr","@id":"https:\/\/www.africa-press.net\/niger\/#\/schema\/person\/2b1cf3cd81a31e3cd26889ca66d677f1"},"headline":"Quelle est l\u2019influence du fleuve Niger sur l\u2019upwelling du golfe de Guin\u00e9e ?","datePublished":"2021-01-12T16:23:53+00:00","mainEntityOfPage":{"@id":"https:\/\/www.africa-press.net\/niger\/toutes-les-actualites\/quelle-est-linfluence-du-fleuve-niger-sur-lupwelling-du-golfe-de-guinee"},"wordCount":423,"commentCount":0,"image":{"@id":"https:\/\/www.africa-press.net\/niger\/toutes-les-actualites\/quelle-est-linfluence-du-fleuve-niger-sur-lupwelling-du-golfe-de-guinee#primaryimage"},"thumbnailUrl":"https:\/\/static.africa-press.net\/niger\/sites\/40\/2021\/01\/39.jpg","articleSection":["Communaut\u00e9","homepage-french","Toutes les actualit\u00e9s"],"inLanguage":"fr-FR","potentialAction":[{"@type":"CommentAction","name":"Comment","target":["https:\/\/www.africa-press.net\/niger\/toutes-les-actualites\/quelle-est-linfluence-du-fleuve-niger-sur-lupwelling-du-golfe-de-guinee#respond"]}]},{"@type":"WebPage","@id":"https:\/\/www.africa-press.net\/niger\/toutes-les-actualites\/quelle-est-linfluence-du-fleuve-niger-sur-lupwelling-du-golfe-de-guinee","url":"https:\/\/www.africa-press.net\/niger\/toutes-les-actualites\/quelle-est-linfluence-du-fleuve-niger-sur-lupwelling-du-golfe-de-guinee","name":"Quelle est l\u2019influence du fleuve Niger sur l\u2019upwelling du golfe de Guin\u00e9e ? - niger","isPartOf":{"@id":"https:\/\/www.africa-press.net\/niger\/#website"},"primaryImageOfPage":{"@id":"https:\/\/www.africa-press.net\/niger\/toutes-les-actualites\/quelle-est-linfluence-du-fleuve-niger-sur-lupwelling-du-golfe-de-guinee#primaryimage"},"image":{"@id":"https:\/\/www.africa-press.net\/niger\/toutes-les-actualites\/quelle-est-linfluence-du-fleuve-niger-sur-lupwelling-du-golfe-de-guinee#primaryimage"},"thumbnailUrl":"https:\/\/static.africa-press.net\/niger\/sites\/40\/2021\/01\/39.jpg","datePublished":"2021-01-12T16:23:53+00:00","author":{"@id":"https:\/\/www.africa-press.net\/niger\/#\/schema\/person\/2b1cf3cd81a31e3cd26889ca66d677f1"},"description":"Africa-Press - Niger.\u00a0En \u00e9t\u00e9 en face du Ghana, le vent de sud-ouest souffle parall\u00e8lement \u00e0 la c\u00f4te et se combine","breadcrumb":{"@id":"https:\/\/www.africa-press.net\/niger\/toutes-les-actualites\/quelle-est-linfluence-du-fleuve-niger-sur-lupwelling-du-golfe-de-guinee#breadcrumb"},"inLanguage":"fr-FR","potentialAction":[{"@type":"ReadAction","target":["https:\/\/www.africa-press.net\/niger\/toutes-les-actualites\/quelle-est-linfluence-du-fleuve-niger-sur-lupwelling-du-golfe-de-guinee"]}]},{"@type":"ImageObject","inLanguage":"fr-FR","@id":"https:\/\/www.africa-press.net\/niger\/toutes-les-actualites\/quelle-est-linfluence-du-fleuve-niger-sur-lupwelling-du-golfe-de-guinee#primaryimage","url":"https:\/\/static.africa-press.net\/niger\/sites\/40\/2021\/01\/39.jpg","contentUrl":"https:\/\/static.africa-press.net\/niger\/sites\/40\/2021\/01\/39.jpg","width":720,"height":405},{"@type":"BreadcrumbList","@id":"https:\/\/www.africa-press.net\/niger\/toutes-les-actualites\/quelle-est-linfluence-du-fleuve-niger-sur-lupwelling-du-golfe-de-guinee#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"Accueil","item":"https:\/\/www.africa-press.net\/niger\/"},{"@type":"ListItem","position":2,"name":"Quelle est l\u2019influence du fleuve Niger sur l\u2019upwelling du golfe de Guin\u00e9e ?"}]},{"@type":"WebSite","@id":"https:\/\/www.africa-press.net\/niger\/#website","url":"https:\/\/www.africa-press.net\/niger\/","name":"niger","description":"Just another Africa News Agency Sites site","potentialAction":[{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https:\/\/www.africa-press.net\/niger\/?s={search_term_string}"},"query-input":{"@type":"PropertyValueSpecification","valueRequired":true,"valueName":"search_term_string"}}],"inLanguage":"fr-FR"},{"@type":"Person","@id":"https:\/\/www.africa-press.net\/niger\/#\/schema\/person\/2b1cf3cd81a31e3cd26889ca66d677f1","name":"cfeditorfr"}]}},"_links":{"self":[{"href":"https:\/\/www.africa-press.net\/niger\/wp-json\/wp\/v2\/posts\/2086","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.africa-press.net\/niger\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.africa-press.net\/niger\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.africa-press.net\/niger\/wp-json\/wp\/v2\/users\/82"}],"replies":[{"embeddable":true,"href":"https:\/\/www.africa-press.net\/niger\/wp-json\/wp\/v2\/comments?post=2086"}],"version-history":[{"count":0,"href":"https:\/\/www.africa-press.net\/niger\/wp-json\/wp\/v2\/posts\/2086\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.africa-press.net\/niger\/wp-json\/wp\/v2\/media\/2096"}],"wp:attachment":[{"href":"https:\/\/www.africa-press.net\/niger\/wp-json\/wp\/v2\/media?parent=2086"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.africa-press.net\/niger\/wp-json\/wp\/v2\/categories?post=2086"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.africa-press.net\/niger\/wp-json\/wp\/v2\/tags?post=2086"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}