{"id":555,"date":"2013-12-13T08:49:00","date_gmt":"2013-12-13T07:49:00","guid":{"rendered":"https:\/\/kids.esa.int\/thinning_ice_and_rising_sea_levels\/"},"modified":"2026-10-08T00:29:35","modified_gmt":"2026-10-07T22:29:35","slug":"thinning_ice_and_rising_sea_levels","status":"publish","type":"post","link":"https:\/\/kids.esa.int\/fi\/thinning_ice_and_rising_sea_levels\/","title":{"rendered":"J\u00e4\u00e4n ohentuminen ja merenpinnan nousu"},"content":{"rendered":"
\n

ESA:n CryoSat-avaruusluotain on lent\u00e4nyt maapallon pohjois- ja etel\u00e4navan yl\u00e4puolella huhtikuusta 2010 l\u00e4htien. Sen teht\u00e4v\u00e4n\u00e4 on seurata n\u00e4it\u00e4 alueita peitt\u00e4v\u00e4n j\u00e4\u00e4n paksuuden muutoksia.<\/p>\n

Kolmen vuoden havaintojen perusteella CryoSat on vahvistanut, ett\u00e4 arktisen j\u00e4\u00e4n (Pohjoisnapa) tilavuus on pienentynyt. CryoSat on my\u00f6s osoittanut, ett\u00e4 L\u00e4nsi-Antarktiksen j\u00e4\u00e4peite (Etel\u00e4napa) menett\u00e4\u00e4 vuosittain yli 150 kuutiokilometri\u00e4 j\u00e4\u00e4t\u00e4. Se vastaa j\u00e4\u00e4laattaa, joka on 1 km leve\u00e4, 1 km syv\u00e4 ja 150 km pitk\u00e4!<\/p>\n<\/div>\n

Maapallon napa-alueita peitt\u00e4v\u00e4t valtavat j\u00e4\u00e4peitteet eiv\u00e4t ole pysyvi\u00e4. Ne kasvavat kylmempin\u00e4 kausina, joita kutsutaan j\u00e4\u00e4kausiksi, ja kutistuvat, kun l\u00e4mp\u00f6tilat nousevat tai paikalliset olosuhteet muuttuvat. Jopa l\u00e4hes 3 km paksu Antarktiksen j\u00e4\u00e4peite voi olla alttiina n\u00e4ille muutoksille.<\/p>\n

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J\u00e4\u00e4peitteen paksuuden muutos vuodessa<\/figcaption><\/figure>\n

L\u00e4nsi-Antarktikalla tapahtuu parhaillaan nopeaa j\u00e4\u00e4n menetyst\u00e4. CryoSat-satelliitin mittausten mukaan suurin osa t\u00e4st\u00e4 tapahtuu Amundseninmerelle virtaavissa j\u00e4\u00e4tik\u00f6iss\u00e4. J\u00e4\u00e4n ohenemisnopeus nousee jopa 4\u20138 metriin vuodessa niill\u00e4 alueilla, joilla Pine Islandin, Thwaitesin ja Smithin j\u00e4\u00e4tik\u00f6t irtoavat mantereesta ja alkavat kellua merell\u00e4.<\/p>\n

L\u00e4nsi-Antarktiksen j\u00e4\u00e4tik\u00f6iden sulamisen arvioitiin aiheuttaneen maailmanlaajuisen merenpinnan nousun, joka oli 0,28 mm vuodessa vuosina 2005\u20132010. CryoSat-satelliitin uudet tulokset viittaavat kuitenkin siihen, ett\u00e4 alueen vaikutus merenpinnan nousuun on viel\u00e4kin suurempi! T\u00e4m\u00e4 voi johtua joko siit\u00e4, ett\u00e4 j\u00e4\u00e4 ohenee nopeammin kuin tutkijat aiemmin arvelivat, tai siit\u00e4, ett\u00e4 CryoSat antaa tarkemman kuvan kuin muut satelliitit!<\/p>","protected":false},"excerpt":{"rendered":"

Since its launch in April 2010, ESA\u2019s CryoSat spacecraft has been flying over the North and South Poles of our planet. Its mission is to observe changes in the thickness […]<\/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\/2010\/01\/esa_s_ice_mission2\/17894573-2-eng-GB\/ESA_s_ice_mission.jpg","esa_banner_description":"ESA's ice mission","esa_banner_credit":"ESA\/AOES Medialab","esa_banner_licence":"ESA Standard Licence","esa_banner_detail_url":"https:\/\/www.esa.int\/ESA_Multimedia\/Images\/2010\/01\/ESA_s_ice_mission2","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":[64,42,10],"tags":[],"panel":[],"language":[],"age":[],"duration":[],"resource_type":[],"audience":[],"wf_post_folders":[],"class_list":["post-555","post","type-post","status-publish","format-standard","hentry","category-climate-change","category-earth","category-learn"],"jetpack_sharing_enabled":true,"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/posts\/555","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/users\/5"}],"replies":[{"embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/comments?post=555"}],"version-history":[{"count":4,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/posts\/555\/revisions"}],"predecessor-version":[{"id":4547,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/posts\/555\/revisions\/4547"}],"wp:attachment":[{"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/media?parent=555"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/categories?post=555"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/tags?post=555"},{"taxonomy":"panel","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/panel?post=555"},{"taxonomy":"language","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/language?post=555"},{"taxonomy":"age","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/age?post=555"},{"taxonomy":"duration","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/duration?post=555"},{"taxonomy":"resource_type","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/resource_type?post=555"},{"taxonomy":"audience","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/audience?post=555"},{"taxonomy":"wf_post_folders","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/wf_post_folders?post=555"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}