{"id":1950,"date":"2025-08-18T10:43:49","date_gmt":"2025-08-18T08:43:49","guid":{"rendered":"https:\/\/acriv.org\/WP\/?page_id=1950"},"modified":"2025-08-18T10:46:43","modified_gmt":"2025-08-18T08:46:43","slug":"%e2%9b%88%ef%b8%8fmto-formation-des-nuages","status":"publish","type":"page","link":"https:\/\/acriv.org\/WP\/%e2%9b%88%ef%b8%8fmto-formation-des-nuages\/","title":{"rendered":"\u26c8\ufe0fMTO : FORMATION DES NUAGES"},"content":{"rendered":"\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"700\" height=\"375\" src=\"https:\/\/acriv.org\/WP\/wp-content\/uploads\/2025\/08\/e54639_1df1962ad8184767a0d1b294b23b6200.avif\" alt=\"\" class=\"wp-image-1951\"\/><\/figure>\n\n\n\n<p>\ud83c\udf26\ufe0f ! La formation des nuages repose sur des principes de <strong>physique de l\u2019atmosph\u00e8re<\/strong> et de <strong>cycle de l\u2019eau<\/strong>. <\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">\ud83c\udf0a \u00c9tape 1 \u2013 L\u2019\u00e9vaporation et la transpiration<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li>L\u2019<strong>eau<\/strong> des oc\u00e9ans, lacs, rivi\u00e8res, sols et v\u00e9g\u00e9tation s\u2019\u00e9vapore sous l\u2019effet de la chaleur du Soleil.<\/li>\n\n\n\n<li>Les plantes rel\u00e2chent aussi de la vapeur d\u2019eau (transpiration).<br>\ud83d\udc49 R\u00e9sultat : l\u2019air contient de la <strong>vapeur d\u2019eau invisible<\/strong>.<\/li>\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">\ud83c\udf21\ufe0f \u00c9tape 2 \u2013 Le refroidissement de l\u2019air<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Quand une masse d\u2019air humide <strong>s\u2019\u00e9l\u00e8ve<\/strong> (par convection, par soul\u00e8vement frontal, ou par effet orographique au passage d\u2019une montagne), la pression diminue.<\/li>\n\n\n\n<li>Moins de pression = l\u2019air se <strong>dilate<\/strong> = il se <strong>refroidit<\/strong>.<br>\ud83d\udc49 C\u2019est ce qu\u2019on appelle le <strong>refroidissement adiabatique<\/strong>.<\/li>\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">\ud83d\udca7 \u00c9tape 3 \u2013 La condensation<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Plus l\u2019air est froid, moins il peut contenir de vapeur d\u2019eau.<\/li>\n\n\n\n<li>Quand l\u2019air atteint sa <strong>temp\u00e9rature de saturation<\/strong> (point de ros\u00e9e), la vapeur d\u2019eau se condense en fines <strong>gouttelettes<\/strong> ou en <strong>cristaux de glace<\/strong> si la temp\u00e9rature est tr\u00e8s basse.<br>\ud83d\udc49 Ce regroupement de micro-gouttelettes forme le <strong>nuage<\/strong>.<\/li>\n<\/ul>\n\n\n\n<p>\u26a0\ufe0f Mais pour que la condensation se produise, il faut des <strong>noyaux de condensation<\/strong> (poussi\u00e8res, sels marins, pollens, particules fines) sur lesquels les gouttelettes se fixent.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">\ud83c\udf29\ufe0f \u00c9tape 4 \u2013 L\u2019\u00e9volution du nuage<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Si l\u2019air continue \u00e0 monter et \u00e0 s\u2019humidifier \u2192 le nuage grandit (ex : cumulus qui devient cumulonimbus).<\/li>\n\n\n\n<li>Si le nuage devient assez \u00e9pais, les gouttelettes fusionnent \u2192 elles deviennent trop lourdes pour rester en suspension \u2192 <strong>pr\u00e9cipitations<\/strong> (pluie, neige, gr\u00eale).<\/li>\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">\ud83d\udd0e Les principaux m\u00e9canismes de formation des nuages<\/h2>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Convection thermique<\/strong> : l\u2019air chaud monte (cumulus, cumulonimbus).<\/li>\n\n\n\n<li><strong>Soul\u00e8vement orographique<\/strong> : l\u2019air est forc\u00e9 de monter en rencontrant une montagne (nuages sur les reliefs).<\/li>\n\n\n\n<li><strong>Soul\u00e8vement frontal<\/strong> : l\u2019air chaud glisse sur l\u2019air froid (front chaud) ou est forc\u00e9 de monter par de l\u2019air froid (front froid) \u2192 altostratus, nimbostratus.<\/li>\n\n\n\n<li><strong>Refroidissement nocturne<\/strong> : au sol, formation de stratus ou brouillard.<\/li>\n<\/ol>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<p>\ud83d\udc49 En r\u00e9sum\u00e9 :<br>Les nuages se forment quand <strong>l\u2019air humide monte, se refroidit et condense sa vapeur d\u2019eau<\/strong> autour de particules en suspension.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\ud83c\udf26\ufe0f ! La formation des nuages repose sur des principes de physique de l\u2019atmosph\u00e8re et de cycle de l\u2019eau. \ud83c\udf0a \u00c9tape 1 \u2013 L\u2019\u00e9vaporation et la transpiration \ud83c\udf21\ufe0f \u00c9tape 2 \u2013 Le refroidissement de l\u2019air \ud83d\udca7 \u00c9tape 3 \u2013 La condensation \u26a0\ufe0f Mais pour que la condensation se produise, il faut des noyaux de condensation (poussi\u00e8res, sels marins, pollens, particules<\/p>\n<p><a class=\"more-link\" href=\"https:\/\/acriv.org\/WP\/%e2%9b%88%ef%b8%8fmto-formation-des-nuages\/\">Read More<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-1950","page","type-page","status-publish","hentry"],"jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/acriv.org\/WP\/wp-json\/wp\/v2\/pages\/1950","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/acriv.org\/WP\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/acriv.org\/WP\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/acriv.org\/WP\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/acriv.org\/WP\/wp-json\/wp\/v2\/comments?post=1950"}],"version-history":[{"count":2,"href":"https:\/\/acriv.org\/WP\/wp-json\/wp\/v2\/pages\/1950\/revisions"}],"predecessor-version":[{"id":1956,"href":"https:\/\/acriv.org\/WP\/wp-json\/wp\/v2\/pages\/1950\/revisions\/1956"}],"wp:attachment":[{"href":"https:\/\/acriv.org\/WP\/wp-json\/wp\/v2\/media?parent=1950"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}