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Yankin kankara na Gabashin Antarctic

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Yankin kankara na Gabashin Antarctic
Gileshiya (Tsaunin kankara)
Bayanai
Bangare na Antarctic ice sheet (en) Fassara
Nahiya Antatika
Ƙasa no value
Wuri
Map
 80°S 80°E / 80°S 80°E / -80; 80
Condominium (en) FassaraAntarctic Treaty area (en) Fassara

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, [1] 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 2.2 kilometres (1.4 mi) kauri a matsakaici kuma yana da 4,897 metres (16,066 ft) a mafi kauri.[2] 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 [3] yana haifar da rahoton yanayi sanyi na kusan -100 ° C (−148 ° F). [4] [5] 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.[3]

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.[6][7] 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.[8] 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. [9]

Bayyanawa

[gyara sashe | gyara masomin]
Wurin da zane na Tafkin Vostok, sanannen tafkin subglacial a ƙarƙashin Gabashin Antarctic Ice Sheet.

Ice Sheet na Gabashin Antarctic yana saman Garkuwar Antarctic ta Gabas - craton (tsayayyen yanki na ɓawon ƙasa ) mai girman 10,200,000 km2 (3,900,000 sq mi) , wanda ke lissafin kusan kashi 73% na dukkan ƙasar Antarctic. [10] Gabashin Antarctica ya bambanta da yammacin Antarctica saboda kasancewar tsaunukan Transantarctic, wanda ya kai kusan 3,500 km (2,200 mi) daga Tekun Weddell zuwa Tekun Ross, kuma suna da faɗin 100–300 km (62–186 mi) .

Yankin kankara yana da matsakaicin kauri na kusan kilomita 3 kilometres (1.9 mi)" (1.4 kilometres (2.5 mi) . Mafi kauri kankara a Antarctica yana kusa da Adélie Land kusa da kudu maso gabashin bakin teku, a Astrolabe Subglacial Basin, inda ya auna 4,897 metres (16,066 ft) 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 2.7 kilometres (1.7 mi) mi) kuma kusan daidai yake da girman Alps na Turai.[11][12] Sakamakon haka, kaurin kankara a kan wadannan duwatsu ya kasance daga kusan 1 mi) a kan tsaunuka zuwa kusan 3 mi) a saman kwari.[13]

Tashar bincike ta Kudu.

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 -10 °C (32 °F) ° C (−148 ° F).[4][5][3] 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). [13]

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.[14]

Tarihin yanayin ƙasa

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Canjin yanayin zafi na polar a duk lokacin Cenozoic, yana nuna glaciation na Antarctica zuwa ƙarshen Eocene, narkewa kusa da ƙarshen Oligocene da sakewar Miocene.

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.[15]

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. [16] Tun daga wannan lokacin, ya kasance mafi kwanciyar hankali, yana fuskantar canjin "ƙananan" a cikin girmanta a cikin shekaru miliyan 8 da suka gabata. [17] Yayin da har yanzu ya ragu da akalla 500 metres (1,600 ft) yayin lokacin Pleistocene, kuma ta ƙasa da 50 metres (160 ft) tun daga Ƙarshe Glacial Maximum, yankin ƙasar da ƙanƙara ta rufe a Gabashin Antarctica ya kasance iri ɗaya ne. [18] 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. [19] [20] [21] [22]

Manazarta

[gyara sashe | gyara masomin]
  1. ↑ Galeotti, Simone; DeConto, Robert; Naish, Timothy; Stocchi, Paolo; Florindo, Fabio; Pagani, Mark; Barrett, Peter; Bohaty, Steven M.; Lanci, Luca; Pollard, David; Sandroni, Sonia; Talarico, Franco M.; Zachos, James C. (10 March 2016). "Antarctic Ice Sheet variability across the Eocene-Oligocene boundary climate transition". Science. 352 (6281): 76–80. doi:10.1126/science.aab066.
  2. ↑ Fretwell, P.; Pritchard, H. D.; Vaughan, D. G.; Bamber, J. L.; Barrand, N. E.; Bell, R.; Bianchi, C.; Bingham, R. G.; Blankenship, D. D. (2013-02-28). "Bedmap2: improved ice bed, surface and thickness datasets for Antarctica". The Cryosphere. 7 (1): 375–393. Bibcode:2013TCry....7..375F. doi:10.5194/tc-7-375-2013. ISSN 1994-0424. |hdl-access= requires |hdl= (help)
  3. ↑ 3.0 3.1 3.2 Singh, Hansi A.; Polvani, Lorenzo M. (10 January 2020). "Low Antarctic continental climate sensitivity due to high ice sheet orography". npj Climate and Atmospheric Science (in Turanci). 3. doi:10.1038/s41612-020-00143-w. S2CID 222179485. Cite error: Invalid <ref> tag; name "Singh2020" defined multiple times with different content
  4. ↑ 4.0 4.1 Scambos, T. A.; Campbell, G. G.; Pope, A.; Haran, T.; Muto, A.; Lazzara, M.; Reijmer, C. H.; Van Den Broeke, M. R. (25 June 2018). "Ultralow Surface Temperatures in East Antarctica From Satellite Thermal Infrared Mapping: The Coldest Places on Earth". Geophysical Research Letters. 45 (12): 6124–6133. Bibcode:2018GeoRL..45.6124S. doi:10.1029/2018GL078133. |hdl-access= requires |hdl= (help) Cite error: Invalid <ref> tag; name "Scambos2018" defined multiple times with different content
  5. ↑ 5.0 5.1 Vizcarra, Natasha (25 June 2018). "New study explains Antarctica's coldest temperatures" (in Turanci). National Snow and Ice Data Center. Retrieved 10 January 2024. Cite error: Invalid <ref> tag; name "VizcarraNSIDC2018" defined multiple times with different content
  6. ↑ Xin, Meijiao; Clem, Kyle R; Turner, John; Stammerjohn, Sharon E; Zhu, Jiang; Cai, Wenju; Li, Xichen (2 June 2023). "West-warming East-cooling trend over Antarctica reversed since early 21st century driven by large-scale circulation variation". Environmental Research Letters. 18 (6): 064034. doi:10.1088/1748-9326/acd8d4.
  7. ↑ Xin, Meijiao; Li, Xichen; Stammerjohn, Sharon E; Cai, Wenju; Zhu, Jiang; Turner, John; Clem, Kyle R; Song, Chentao; Wang, Wenzhu; Hou, Yurong (17 May 2023). "A broadscale shift in antarctic temperature trends". Climate Dynamics. 61: 4623–4641. doi:10.1007/s00382-023-06825-4.
  8. ↑ Eric Steig; Gavin Schmidt (2004-12-03). "Antarctic cooling, global warming?". Real Climate. Retrieved 2008-08-14. At first glance this seems to contradict the idea of "global" warming, but one needs to be careful before jumping to this conclusion. A rise in the global mean temperature does not imply universal warming. Dynamical effects (changes in the winds and ocean circulation) can have just as large an impact, locally as the radiative forcing from greenhouse gases. The temperature change in any particular region will in fact be a combination of radiation-related changes (through greenhouse gases, aerosols, ozone and the like) and dynamical effects. Since the winds tend to only move heat from one place to another, their impact will tend to cancel out in the global mean.
  9. ↑ Steig, E. J.; Schneider, D. P.; Rutherford, S. D.; Mann, M. E.; Comiso, J. C.; Shindell, D. T. (2009). "Warming of the Antarctic ice-sheet surface since the 1957 International Geophysical Year". Nature. 457 (7228): 459–462. Bibcode:2009Natur.457..459S. doi:10.1038/nature07669. PMID 19158794. S2CID 4410477.
  10. ↑ Drewry, David J. (November 1976). "Sedimentary basins of the east antarctic craton from geophysical evidence". Tectonophysics. 36 (1–3): 301–314. Bibcode:1976Tectp..36..301J. doi:10.1016/0040-1951(76)90023-8.
  11. ↑ Sara E. Pratt (6 February 2012). "Unearthing Antarctica's mysterious mountains". Earth Magazine. Retrieved 15 January 2024.
  12. ↑ Robin Bell (12 November 2008). "Dispatches from the Bottom of the Earth: An Antarctic Expedition in Search of Large Mountains Encased in Ice". Scientific American. Retrieved 15 January 2024.
  13. ↑ 13.0 13.1 Davies, Bethan (22 June 2020). "East Antarctic Ice Sheet". AntarcticGlaciers.org. Cite error: Invalid <ref> tag; name "EAISDavies" defined multiple times with different content
  14. ↑ Bush, W. M. (October 1989). "Antarctica and international law: a collection of inter-state and national documents". American Journal of International Law (in Turanci). 83 (4): 959–964. doi:10.2307/2203393. ISBN 978-0-379-20321-9.
  15. ↑ Galeotti, Simone; DeConto, Robert; Naish, Timothy; Stocchi, Paolo; Florindo, Fabio; Pagani, Mark; Barrett, Peter; Bohaty, Steven M.; Lanci, Luca; Pollard, David; Sandroni, Sonia; Talarico, Franco M.; Zachos, James C. (10 March 2016). "Antarctic Ice Sheet variability across the Eocene-Oligocene boundary climate transition". Science. 352 (6281): 76–80. doi:10.1126/science.aab066.
  16. ↑ Barr, Iestyn D.; Spagnolo, Matteo; Rea, Brice R.; Bingham, Robert G.; Oien, Rachel P.; Adamson, Kathryn; Ely, Jeremy C.; Mullan, Donal J.; Pellitero, Ramón; Tomkins, Matt D. (21 September 2022). "60 million years of glaciation in the Transantarctic Mountains". Nature Communications (in Turanci). 13 (1): 5526. doi:10.1038/s41467-022-33310-z. ISSN 2041-1723. |hdl-access= requires |hdl= (help)
  17. ↑ Shakun, Jeremy D.; et al. (2018). "Minimal East Antarctic Ice Sheet retreat onto land during the past eight million years". Nature. 558 (7709): 284–287. Bibcode:2018Natur.558..284S. doi:10.1038/s41586-018-0155-6. OSTI 1905199. PMID 29899483. S2CID 49185845.
  18. ↑ Yusuke Suganuma; Hideki Miura; Albert Zondervan; Jun'ichi Okuno (August 2014). "East Antarctic deglaciation and the link to global cooling during the Quaternary: evidence from glacial geomorphology and 10Be surface exposure dating of the Sør Rondane Mountains, Dronning Maud Land". Quaternary Science Reviews. 97: 102–120. Bibcode:2014QSRv...97..102S. doi:10.1016/j.quascirev.2014.05.007.
  19. ↑ Voosen, Paul (2018-12-18). "Discovery of recent Antarctic ice sheet collapse raises fears of a new global flood". Science (in Turanci). Retrieved 2018-12-28.
  20. ↑ Turney, Chris S. M.; Fogwill, Christopher J.; Golledge, Nicholas R.; McKay, Nicholas P.; Sebille, Erik van; Jones, Richard T.; Etheridge, David; Rubino, Mauro; Thornton, David P.; Davies, Siwan M.; Ramsey, Christopher Bronk (2020-02-11). "Early Last Interglacial ocean warming drove substantial ice mass loss from Antarctica". Proceedings of the National Academy of Sciences (in Turanci). 117 (8): 3996–4006. Bibcode:2020PNAS..117.3996T. doi:10.1073/pnas.1902469117. ISSN 0027-8424. PMC 7049167. PMID 32047039.
  21. ↑ Lau, Sally C. Y.; Wilson, Nerida G.; Golledge, Nicholas R.; Naish, Tim R.; Watts, Phillip C.; Silva, Catarina N. S.; Cooke, Ira R.; Allcock, A. Louise; Mark, Felix C.; Linse, Katrin (21 December 2023). "Genomic evidence for West Antarctic Ice Sheet collapse during the Last Interglacial". Science (in Turanci). 382 (6677): 1384–1389. doi:10.1126/science.ade0664.
  22. ↑ AHMED, Issam. "Antarctic octopus DNA reveals ice sheet collapse closer than thought". phys.org (in Turanci). Retrieved 2023-12-23.
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