{"id":1081,"date":"2009-10-30T10:28:00","date_gmt":"2009-10-30T09:28:00","guid":{"rendered":"https:\/\/kids.esa.int\/esa_satellite_prepares_for_water_watch\/"},"modified":"2026-10-08T00:35:47","modified_gmt":"2026-10-07T22:35:47","slug":"esa_satellite_prepares_for_water_watch","status":"publish","type":"post","link":"https:\/\/kids.esa.int\/fr\/esa_satellite_prepares_for_water_watch\/","title":{"rendered":"Le satellite de l\u2019ESA se pr\u00e9pare \u00e0 observer l\u2019eau"},"content":{"rendered":"<div class=\"lede\">\n<p>Pour un extraterrestre qui passerait au-dessus de la Terre, notre plan\u00e8te ressemblerait \u00e0 un monde d\u2019eau recouvert essentiellement d\u2019oc\u00e9ans et de nuages. Sans ce pr\u00e9cieux liquide, il n\u2019y aurait pas de vie sur Terre. Mais il reste encore beaucoup de choses que nous ignorons sur l\u2019eau et son impact sur le climat. La prochaine mission Earth Explorer de l\u2019ESA, baptis\u00e9e SMOS, devrait pouvoir apporter des r\u00e9ponses.<\/p>\n<\/div>\n<p>L\u2019eau est la seule substance naturelle sur Terre existant sous forme de gaz, de liquide ou de solide. Lorsqu\u2019elle est chauff\u00e9e par le Soleil, l\u2019eau s\u2019\u00e9vapore et se transforme en gaz (vapeur d\u2019eau). Ce gaz s\u2019\u00e9l\u00e8ve et refroidit, formant les nuages et la pluie. La pluie retombe sur la surface de la Terre, compl\u00e9tant le cycle de l\u2019eau.<\/p>\n<figure class=\"wp-block-image size-large\" data-width=\"2490\" data-credit=\"ESA - AOES Medialab\" data-detail-url=\"https:\/\/www.esa.int\/ESA_Multimedia\/Images\/2009\/07\/SMOS_BR-2782\" data-licence=\"ESA Standard Licence\" data-licence-url=\"https:\/\/www.esa.int\/ESA_Multimedia\/Terms_and_conditions_of_use_of_images_and_videos_available_on_the_esa_website\"><img decoding=\"async\" loading=\"lazy\" style=\"max-width:100%;height:auto\" src=\"https:\/\/www.esa.int\/var\/esa\/storage\/images\/esa_multimedia\/images\/2009\/07\/smos_br-2782\/17885841-2-eng-GB\/SMOS_BR-278.jpg\" alt=\"SMOS BR-278\"><\/figure>\n<p>Si la vapeur d\u2019eau provient largement des oc\u00e9ans, \u00e0 peu pr\u00e8s un-dixi\u00e8me est lib\u00e9r\u00e9 par les plantes et l\u2019\u00e9vaporation du sol. Cependant, si le sol est trop humide, inondations et \u00e9rosion peuvent se produire. Inversement, un sol trop sec peut se transformer en d\u00e9sert. A ce jour, quelques rares mesures de l\u2019humidit\u00e9 du sol ont \u00e9t\u00e9 effectu\u00e9es, mais cela va changer avec le lancement de SMOS.<\/p>\n<p>Le satellite va \u00e9galement mesurer la salinit\u00e9 (la teneur en sel) des oc\u00e9ans, recherchant les zones beaucoup plus sal\u00e9es et doncplus denses. De telles variations ont un impact sur les courants oc\u00e9aniques, qui \u00e0 leur tour influent sur le climat.<\/p>\n<p>SMOS transporte \u00e0 son bord un instrument sp\u00e9cial destin\u00e9 \u00e0 mesurer l\u2019humidit\u00e9 des sols et la salinit\u00e9 des oc\u00e9ans. 69 r\u00e9cepteurs plac\u00e9s sur des bras en Y mesureront le rayonnement micro-onde \u00e9mis par la surface. Ils pourront d\u00e9tecter l\u2019humidit\u00e9 des sols dans une plage de pr\u00e9cision de 4 % - ce qui revient \u00e0 d\u00e9tecter l\u2019\u00e9quivalent d\u2019une cuill\u00e8re \u00e0 caf\u00e9 d\u2019eau dans une poign\u00e9e de terre s\u00e8che. Durant la mission de trois ans, SMOS fournira la premi\u00e8re cartographie de l\u2019humidit\u00e9 des sols et de la salinit\u00e9 des oc\u00e9ans jamais effectu\u00e9e depuis l\u2019espace.<\/p>","protected":false},"excerpt":{"rendered":"<p>To a passing alien, Earth would appear as a water world, largely covered by oceans and clouds. Without this precious liquid, life on Earth would not exist. However, there is [&hellip;]<\/p>\n","protected":false},"author":5,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"esa_banner_image":"https:\/\/www.esa.int\/var\/esa\/storage\/images\/esa_multimedia\/images\/2009\/09\/smos_in_orbit2\/18245588-2-eng-GB\/SMOS_in_orbit.jpg","esa_banner_description":"SMOS in orbit","esa_banner_credit":"ESA\/AOES Medialab","esa_banner_licence":"ESA Standard Licence","esa_banner_detail_url":"https:\/\/www.esa.int\/ESA_Multimedia\/Images\/2009\/09\/SMOS_in_orbit2","esa_external_url":"","esa_external_new_window":false,"_jetpack_feature_clip_id":0,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_post_was_ever_published":true},"categories":[42,10,66],"tags":[],"panel":[],"language":[],"age":[],"duration":[],"resource_type":[],"audience":[],"wf_post_folders":[],"class_list":["post-1081","post","type-post","status-publish","format-standard","hentry","category-earth","category-learn","category-water-world"],"jetpack_sharing_enabled":true,"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/posts\/1081","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/users\/5"}],"replies":[{"embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/comments?post=1081"}],"version-history":[{"count":4,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/posts\/1081\/revisions"}],"predecessor-version":[{"id":4840,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/posts\/1081\/revisions\/4840"}],"wp:attachment":[{"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/media?parent=1081"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/categories?post=1081"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/tags?post=1081"},{"taxonomy":"panel","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/panel?post=1081"},{"taxonomy":"language","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/language?post=1081"},{"taxonomy":"age","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/age?post=1081"},{"taxonomy":"duration","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/duration?post=1081"},{"taxonomy":"resource_type","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/resource_type?post=1081"},{"taxonomy":"audience","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/audience?post=1081"},{"taxonomy":"wf_post_folders","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/wf_post_folders?post=1081"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}