Yankin kankara na Gabashin Antarctic

Gabashin Antarctic Ice Sheet (**EAIS**) yana tsakanin 45 ° yamma da 168 ° gabas a tsawon lokaci. An fara kafa shi ne a kusa da shekaru miliyan 34 da suka gabata,  kuma shine mafi girman kankara a duk duniya, tare da girma fiye da kankara na Greenland ko West Antarctic Ice Sheet (WAIS), wanda Dutsen Transantarctic ya raba shi. Yankin kankara yana kusa da    kauri a matsakaici kuma yana da    a mafi kauri. Har ila yau, gida ne ga Kudancin Kudancin, Kudancin Magnetic da Amundsen-Scott Kudancin Pole Station.

Yankin EAIS shine wuri mafi bushewa, mafi iska, da kuma mafi sanyi a Duniya. Rashin danshi a cikin iska, babban albedo daga dusar ƙanƙara da kuma tsawo mai tsawo  yana haifar da rahoton yanayi sanyi na kusan -100 ° C (−148 ° F).   Shi ne kawai wuri a Duniya sanyi isa domin canjin zafin jiki na yanayi ya faru akai-akai. Wato, yayin da yanayi ya fi zafi a kusa da farfajiyar kuma ya zama mai sanyi a mafi girman tsawo, yanayi a lokacin hunturu na Antarctic ya fi sanyi a farfajilar fiye da tsakiya. Sakamakon haka, iskar gas a zahiri tana kama zafi a cikin matsakaicin yanayi kuma tana rage kwarararta zuwa farfajiya yayin da juyin zafin jiki ke ci gaba.

Saboda wadannan dalilai, Gabashin Antarctica ya sami ɗan sanyaya na shekaru da yawa yayin da sauran duniya suka yi zafi sakamakon Canjin yanayi. Bayyanawar zafi a Gabashin Antarctica kawai ya fara faruwa tun daga shekara ta 2000, kuma ba a gano shi ba har zuwa 2020s. A farkon shekarun 2000, sanyaya a Gabashin Antarctica wanda ya fi ƙarfin dumama a kan sauran nahiyar ana fassara shi sau da yawa ta hanyar kafofin watsa labarai kuma a wasu lokuta ana amfani dashi azaman jayayya don musanta canjin yanayi. Bayan shekara ta 2009, ci gaba a cikin rikodin zafin jiki na Antarctica ya tabbatar da cewa dumama a kan Yammacin Antarctica ya haifar da dumama a duk faɗin nahiyar tun daga shekara ta 1957. 

## Bayyanawa

Ice Sheet na Gabashin Antarctic yana saman Garkuwar Antarctic ta Gabas - craton (tsayayyen yanki na ɓawon ƙasa ) mai girman   , wanda ke lissafin kusan kashi 73% na dukkan ƙasar Antarctic.  Gabashin Antarctica ya bambanta da yammacin Antarctica saboda kasancewar tsaunukan Transantarctic, wanda ya kai kusan  daga Tekun Weddell zuwa Tekun Ross, kuma suna da faɗin  . 

Yankin kankara yana da matsakaicin kauri na kusan kilomita " (1. . Mafi kauri kankara a Antarctica yana kusa da Adélie Land kusa da kudu maso gabashin bakin teku, a Astrolabe Subglacial Basin, inda ya auna    a kusa da 2013. Yawancin kankara sun riga sun kasance a wani tsawo mai tsawo: musamman, Dome Argus Plateau yana da matsakaicin tsawo na kusan kilomita 4 (2.5 , kuma duk da haka yana ƙarƙashin Dutsen Gamburtsev, wanda ke da matsakaitan tsawo na   mi) kuma kusan daidai yake da girman Alps na Turai. Sakamakon haka, kaurin kankara a kan wadannan duwatsu ya kasance daga kusan 1  mi) a kan tsaunuka zuwa kusan 3  mi) a saman kwari.

Wadannan tsaunuka masu tsawo sune muhimmiyar dalilin da ya sa kankara ta fi bushewa, iska, da kuma sanyi a Duniya. Dome A a cikin takamaiman saiti ya ba da rahoton rikodin zafin jiki na kusan -1 ° C (−148 ° F). Yankunan da ba su da kankara a Gabashin Antarctica sune inda akwai karancin ruwan sama na shekara-shekara don samar da kankara, wanda shine yanayin da ake kira McMurdo Dry Valleys na Kudancin Victoria Land. Wani banbanci shine tabkuna na subglacial, wanda ke faruwa da zurfi a ƙarƙashin kankara cewa matsin lamba yana ƙasa da 0 ° C (32 ° F). 

Kasashe da yawa sun yi ikirarin yankin a Antarctica. A cikin EAIS, Ƙasar Ingila, Faransa, Norway, Ostiraliya, Chile da Argentina duk suna da'awar wani ɓangare (wani lokacin suna haɗuwa) a matsayin yankinsu.

## Tarihin yanayin ƙasa

Duk da yake an san ƙananan kankara da kankara a Antarctica tun a kalla lokacin Late Palaeocene, shekaru miliyan 60 da suka gabata,  takardar kankara mai kyau ba ta fara samuwa ba har sai Eocene-Oligocene ya faru game da shekaru miliyan 34 da suka gabata. Da farko ba ta da kwanciyar hankali, kuma ba ta girma ba don rufe dukan nahiyar har sai shekaru miliyan 32.8 da suka gabata, lokacin da matakan CO2 suka kara raguwa zuwa ƙasa da 600 ppm.

Bayan haka, Tsarin Kankara na Gabashin Antarctic ya ragu sosai a lokacin Mafi kyawun yanayi na Miocene na Tsakiya shekaru miliyan 15 da suka gabata, duk da haka ya fara farfadowa kusan shekaru miliyan 13.96 da suka gabata.  Tun daga wannan lokacin, ya kasance mafi kwanciyar hankali, yana fuskantar canjin "ƙananan" a cikin girmanta a cikin shekaru miliyan 8 da suka gabata.  Yayin da har yanzu ya ragu da akalla  yayin lokacin Pleistocene, kuma ta ƙasa da  tun daga Ƙarshe Glacial Maximum, yankin ƙasar da ƙanƙara ta rufe a Gabashin Antarctica ya kasance iri ɗaya ne.  Bambance-bambancen, ƙaramin kankara na yammacin Antarctic ana tsammanin ya rushe sosai a kwanan nan kamar lokacin Eemian, kimanin shekaru 125,000 da suka wuce.     

## Manazarta