{"id":16104,"date":"2023-01-27T11:11:11","date_gmt":"2023-01-27T10:11:11","guid":{"rendered":"https:\/\/www.cerege.fr\/?page_id=16104"},"modified":"2023-03-21T10:22:16","modified_gmt":"2023-03-21T09:22:16","slug":"diat-17","status":"publish","type":"page","link":"https:\/\/www.cerege.fr\/fr\/sciences\/climat\/projets-climat\/diat-17\/","title":{"rendered":"DIAT-17"},"content":{"rendered":"\t\t<div data-elementor-type=\"wp-page\" data-elementor-id=\"16104\" class=\"elementor elementor-16104\" data-elementor-post-type=\"page\">\n\t\t\t\t\t\t<section class=\"elementor-section elementor-top-section elementor-element elementor-element-17554b0d elementor-section-full_width elementor-section-height-min-height elementor-section-height-default elementor-section-items-middle\" data-id=\"17554b0d\" data-element_type=\"section\" data-e-type=\"section\" data-settings=\"{&quot;background_background&quot;:&quot;classic&quot;}\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-8cd3de2\" data-id=\"8cd3de2\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap\">\n\t\t\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section class=\"elementor-section elementor-top-section elementor-element elementor-element-46cd24f6 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"46cd24f6\" data-element_type=\"section\" data-e-type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-3b8c1499\" data-id=\"3b8c1499\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-20156eb elementor-widget elementor-widget-shortcode\" data-id=\"20156eb\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"shortcode.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t<div class=\"elementor-shortcode\"><nav aria-label=\"breadcrumbs\">\n            <div class=\"breadcrumb-container theme1\">\n                <ol>\n                                    <\/ol>\n            <\/div>\n        <\/nav>    <script type=\"application\/ld+json\">\n        {\n            \"@context\": \"http:\/\/schema.org\",\n            \"@type\": \"BreadcrumbList\",\n            \"itemListElement\": [\n                            ]\n        }\n    <\/script>\n   \n    <script>\n            <\/script>\n<\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<section class=\"elementor-section elementor-inner-section elementor-element elementor-element-6002b58f elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"6002b58f\" data-element_type=\"section\" data-e-type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-wide\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-50 elementor-inner-column elementor-element elementor-element-563b87ee\" data-id=\"563b87ee\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-520922e8 elementor-widget elementor-widget-text-editor\" data-id=\"520922e8\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p>L&#8217;humidit\u00e9 atmosph\u00e9rique relative (HR) est un param\u00e8tre climatique majeur qui est mal estim\u00e9 par les mod\u00e8les climatiques globaux. Les comparaisons entre mod\u00e8les et donn\u00e9es pour la p\u00e9riode pr\u00e9-instrumentale sont n\u00e9cessaires \u00e0 l&#8217;am\u00e9lioration des mod\u00e8les mais se heurtent \u00e0 l&#8217;absence de marqueurs r\u00e9ellement quantitatifs de l&#8217;HR pass\u00e9e. Au cours des 15 derni\u00e8res ann\u00e9es, un effort international a \u00e9t\u00e9 fait pour d\u00e9velopper l&#8217;utilisation de la composition isotopique de l&#8217;oxyg\u00e8ne triple de la mol\u00e9cule d&#8217;eau (exprim\u00e9e par d<sup>18<\/sup>O, d<sup>17<\/sup>O et <sup>17<\/sup>O-exc\u00e8s) comme marqueur du fractionnement par \u00e9vaporation dont l&#8217;humidit\u00e9 atmosph\u00e9rique relative est le principal moteur.<\/p><p>Dans le projet de validation de concept DIAT-17, nous cherchons \u00e0 d\u00e9terminer si la composition isotopique de l&#8217;oxyg\u00e8ne triple des frustules de diatom\u00e9es peut \u00eatre utilis\u00e9e pour enregistrer la composition isotopique de l&#8217;oxyg\u00e8ne triple de l&#8217;eau du lac, informer sur l&#8217;ampleur de l&#8217;\u00e9vaporation dans l&#8217;\u00e9quilibre hydrologique du lac et avoir le potentiel de compl\u00e9ter la bo\u00eete \u00e0 outils des proxies quantitatifs de l&#8217;humidit\u00e9 relative atmosph\u00e9rique pass\u00e9e.<\/p><p>Dans ce but, la composition isotopique de l&#8217;oxyg\u00e8ne triple des diatom\u00e9es modernes et des \u00e9chantillons d&#8217;eau lacustre de quatre lacs d&#8217;Afrique occidentale et centrale sera \u00e9tudi\u00e9e et le fractionnement (dans le syst\u00e8me isotopique de l&#8217;oxyg\u00e8ne triple) entre l&#8217;eau et les diatom\u00e9es sera d\u00e9fini. Un des lacs a \u00e9t\u00e9 \u00e9quip\u00e9 pour un suivi hydrom\u00e9t\u00e9orologique complet qui nous permettra d&#8217;utiliser le mod\u00e8le de Craig &amp; Gordon pour estimer l&#8217;\u00e9volution de l&#8217;exc\u00e8s de d<sup>18<\/sup>O vs <sup>17<\/sup>O \u00a0de l&#8217;eau du lac avec l&#8217;\u00e9vaporation et l&#8217;humidit\u00e9 relative. Les donn\u00e9es et les estimations seront confront\u00e9es.<\/p><p>Le r\u00e9sultat obtenu sera utilis\u00e9 pour discuter les donn\u00e9es d<sup>18<\/sup>O\u00a0 et <sup>17<\/sup>O-exc\u00e8s des diatom\u00e9es d&#8217;une carotte s\u00e9dimentaire couvrant la p\u00e9riode humide africaine (11000-5000 cal BP yr).<\/p><div>\u00a0<\/div><div>\u00a0<\/div>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t<div class=\"elementor-column elementor-col-50 elementor-inner-column elementor-element elementor-element-bc72ce5\" data-id=\"bc72ce5\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-77f79a69 elementor-widget elementor-widget-text-editor\" data-id=\"77f79a69\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<h2><span style=\"font-weight: normal;\">2022-2023 : INSU LEFE\/IMAGO DIAT-17<br \/><\/span><\/h2><p><em>L&#8217;exc\u00e8s de <sup>17<\/sup>O des diatom\u00e9es : vers un nouveau marqueur hydroclimatique<\/em><\/p><p>\u00a0<\/p><p><strong>Au CEREGE:<br \/>Responsables<\/strong>: <a href=\"https:\/\/www.cerege.fr\/fr\/cerege\/florence-sylvestre\/\">Florence Sylvestre<\/a><strong>, <\/strong><a href=\"https:\/\/www.cerege.fr\/fr\/cerege\/anne-alexandre\/\">Anne Alexandre<\/a><\/p><p><strong>Participants<\/strong>: <a href=\"https:\/\/www.cerege.fr\/fr\/cerege\/christine-vallet-coulomb\/\">Christine Vallet-Coulomb<\/a>, <a href=\"https:\/\/www.cerege.fr\/fr\/cerege\/julie-aleman\/\">Julie Aleman<\/a>,<a href=\"https:\/\/www.cerege.fr\/fr\/cerege\/corinne-sonzogni\/\"> Corinne Sonzogni<\/a><a href=\"https:\/\/www.cerege.fr\/fr\/author\/anne-alexandre\/\" target=\"_blank\" rel=\"noopener\">,<\/a> <a href=\"https:\/\/www.cerege.fr\/fr\/cerege\/jean-charles-mazur\/\">Jean-Charles Mazur<\/a>, <a href=\"https:\/\/www.cerege.fr\/fr\/cerege\/david-au-yang\/\">David Au Yang<\/a>.<\/p><p><em>\u00a0<\/em><\/p><p><strong>Collaborateurs \u00e9trangers:<\/strong> Universit\u00e9 de N&#8217;Djamena, D\u00e9partement G\u00e9o-ressources et R\u00e9servoirs (Tchad)<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-3b7034e elementor-widget elementor-widget-image\" data-id=\"3b7034e\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"image.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<img fetchpriority=\"high\" decoding=\"async\" width=\"800\" height=\"499\" src=\"https:\/\/www.cerege.fr\/wp-content\/uploads\/2023\/01\/FS-GN9011-MG3.png\" class=\"attachment-large size-large wp-image-16320\" alt=\"\" srcset=\"https:\/\/www.cerege.fr\/wp-content\/uploads\/2023\/01\/FS-GN9011-MG3.png 1019w, https:\/\/www.cerege.fr\/wp-content\/uploads\/2023\/01\/FS-GN9011-MG3-300x187.png 300w, https:\/\/www.cerege.fr\/wp-content\/uploads\/2023\/01\/FS-GN9011-MG3-768x479.png 768w, https:\/\/www.cerege.fr\/wp-content\/uploads\/2023\/01\/FS-GN9011-MG3-18x12.png 18w\" sizes=\"(max-width: 800px) 100vw, 800px\" \/>\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<div class=\"elementor-element elementor-element-6ad9d4b1 elementor-widget elementor-widget-spacer\" data-id=\"6ad9d4b1\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"spacer.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t<div class=\"elementor-spacer\">\n\t\t\t<div class=\"elementor-spacer-inner\"><\/div>\n\t\t<\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-15cecca7 elementor-widget elementor-widget-spacer\" data-id=\"15cecca7\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"spacer.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t<div class=\"elementor-spacer\">\n\t\t\t<div class=\"elementor-spacer-inner\"><\/div>\n\t\t<\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<\/div>\n\t\t","protected":false},"excerpt":{"rendered":"<p>L&#8217;humidit\u00e9 atmosph\u00e9rique relative (HR) est un param\u00e8tre climatique majeur qui est mal estim\u00e9 par les mod\u00e8les climatiques globaux. Les comparaisons entre mod\u00e8les et donn\u00e9es pour la p\u00e9riode pr\u00e9-instrumentale sont n\u00e9cessaires [&hellip;]<\/p>\n","protected":false},"author":551,"featured_media":16058,"parent":4955,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"_acf_changed":false,"footnotes":""},"class_list":["post-16104","page","type-page","status-publish","has-post-thumbnail","hentry"],"acf":[],"publishpress_future_action":{"enabled":false,"date":"2026-05-12 18:30:02","action":"change-status","newStatus":"draft","terms":[],"taxonomy":"","extraData":[]},"publishpress_future_workflow_manual_trigger":{"enabledWorkflows":[]},"_links":{"self":[{"href":"https:\/\/www.cerege.fr\/fr\/wp-json\/wp\/v2\/pages\/16104","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.cerege.fr\/fr\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/www.cerege.fr\/fr\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/www.cerege.fr\/fr\/wp-json\/wp\/v2\/users\/551"}],"replies":[{"embeddable":true,"href":"https:\/\/www.cerege.fr\/fr\/wp-json\/wp\/v2\/comments?post=16104"}],"version-history":[{"count":5,"href":"https:\/\/www.cerege.fr\/fr\/wp-json\/wp\/v2\/pages\/16104\/revisions"}],"predecessor-version":[{"id":17816,"href":"https:\/\/www.cerege.fr\/fr\/wp-json\/wp\/v2\/pages\/16104\/revisions\/17816"}],"up":[{"embeddable":true,"href":"https:\/\/www.cerege.fr\/fr\/wp-json\/wp\/v2\/pages\/4955"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.cerege.fr\/fr\/wp-json\/wp\/v2\/media\/16058"}],"wp:attachment":[{"href":"https:\/\/www.cerege.fr\/fr\/wp-json\/wp\/v2\/media?parent=16104"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}