Gishiri na teku na Antarctic

Gishiri na teku na Antarctic shine kankara ta teku na Kudancin Tekun. Ya shimfiɗa daga arewacin arewa a cikin hunturu kuma yana komawa kusan bakin teku a kowane bazara. Ruwan teku mai daskarewa ne wanda yawanci bai kai mita kadan ba. Wannan akasin shelf na kankara ne, wanda aka kafa ta kankara; suna iyo a cikin teku, kuma suna da kauri har zuwa kilomita. Akwai sassa biyu na kankara na teku: kankara mai sauri, wanda ke haɗe da ƙasa; da kankara, wanda ba haka ba ne.

Gishiri na teku wanda ya fito daga Kudancin Tekun yana narkewa daga kasa maimakon farfajiya kamar kankara na Arctic saboda an rufe shi da dusar ƙanƙara a saman. A sakamakon haka, ba a lura da tafkunan da suka narke ba. A matsakaici, kankara na teku na Antarctic ya fi ƙanƙanta, ya fi dumi, ya fi gishiri, kuma ya fi motsawa fiye da kankara na Arctic. Wani bambanci tsakanin kankara guda biyu, shine cewa yayin da akwai raguwar kankara na teku na Arctic, yanayin a Antarctica kusan kusan kwance ne."Understanding climate: Antarctic sea ice extent". NOAA Climate.gov. 14 March 2023. Archived from the original on June 4, 2019. Retrieved 2023-03-26. Ba a yi nazarin kankara na teku na Antarctic sosai idan aka kwatanta da kankara na Arctic ba tunda ba shi da sauƙin isa.

 Auna kankara na teku 


 Yankin 
Rufin kankara na teku na Antarctic yana da yanayi sosai, tare da ƙananan kankara a lokacin rani na austral, yana fadada zuwa yankin da ya yi daidai da na Antarctica a cikin hunturu. Yana da tsawo (~ 18 × 10^6 km2) a watan Satumba (wanda aka kwatanta da yankin Pluto), wanda ke nuna ƙarshen hunturu na austral, kuma yana komawa zuwa mafi ƙarancin (~ 3 × 10^ 6 km2) a cikin Fabrairu.Vaughan, D. G.; Comiso, J. C.; Allison, I.; Carrasco, J.; et al. (2013). "Chapter 4: Observations: Cryosphere" (PDF). IPCC AR5 WG1 2013. pp. 317–382. Sakamakon haka, yawancin kankara na teku na Antarctic shine kankara na shekara ta farko, 'yan mita masu kauri, amma ba a san ainihin kauri ba. Yankin kilomita miliyan 18 ^ 2 na kankara shine murabba'in mita miliyan 18, don haka ga kowane mita na kauri, saboda yawan kankara kusan 0.88 teratonnes / miliyan km ^ 3, nauyin mita na saman kankara na Antarctic yana da kusan 16 teratonnes (tunan mita tiriliyan) a ƙarshen hunturu. An auna rikodin ƙananan kankara na lokacin rani a watan Fabrairun 2022 a murabba'in mil 741,000 (1.9 murabba'i kilomita miliyan) ta Cibiyar Bayanan Snow da Ice ta Kasa.  

Tunda teku daga bakin tekun Antarctic yawanci ya fi zafi fiye da iska da ke sama da shi, yawan kankara na teku yana sarrafawa ta hanyar iskõki da raƙuman ruwa waɗanda ke tura shi zuwa arewa. Idan aka tura shi da sauri, kankara na iya tafiya zuwa arewa kafin ya narke. Yawancin kankara an kafa su ne a bakin tekun, yayin da kankara mai motsawa zuwa arewa ya bar wuraren ruwa mai budewa (polynyas masu zafi na bakin tekun), wanda ke daskarewa da sauri.
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 Kauri 
Saboda kankara ta Antarctic galibi kankara ce ta shekara ta farko, wanda ba shi da kauri kamar kankara ta shekaru da yawa, gabaɗaya ƙasa da 'yan mita kauri. Snowfall da ambaliyar kankara na iya kauri da shi sosai, kuma tsarin Layer na kankara na Antarctic sau da yawa yana da rikitarwa.

 Yanayin baya-bayan nan da canjin yanayi 
Yankin kankara na teku a Antarctica ya bambanta sosai shekara-shekara. Wannan ya sa ya zama da wahala a tantance yanayin, kuma an lura da rikodin rikodin rikodi da ƙananan rikodin tsakanin 2013 da 2023. Halin gabaɗaya tun Nuwamba 1978, farkon Ma'aunin tauraron dan adam, ya kasance kusan a kwance, tare da maki biyu na canji. Daga Nuwamba 1978 zuwa Agusta 2007, matsakaicin yanayin kankara na teku ya kasance kusa da sifili. Wannan ya biyo bayan wani lokaci na anomalies masu kyau daga Satumba 2007 zuwa Agusta 2016, da kuma canji na gaba zuwa mafi yawan anomalies da ke ci gaba har zuwa yanzu. Binciken kididdiga ya nuna cewa tsarin kankara na teku na Antarctic ya sami canjin tsari wanda ke nuna canjin mulki a cikin halayyar tsarin. Raguwar kankara na teku na Antarctic tun daga shekara ta 2016 ya kasance tare da karuwar yanayin zafi na teku,  yana nuna tasirin teku akan asarar da aka lura.   Wannan raguwa a cikin kankara na teku ya bayyana cewa ana motsa shi da farko ta hanyar hanyoyin thermodynamic, maimakon ta hanyar advection na inji.alt=|212x212pxRahoton rage yawan kankara na teku na Antarctic a tsakiyar 2023, masu bincike sun kammala cewa "canjin mulki" na iya faruwa "wanda dangantaka mai mahimmanci a baya ba ta mamaye canjin kankara na ruwa ba".Purich, Ariaan; Doddridge, Edward W. (13 September 2023). "Record low Antarctic sea ice coverage indicates a new sea ice state". Communications Earth & Environment. 4 (1): 314. Bibcode:2023ComEE...4..314P. doi:10.1038/s43247-023-00961-9.alt=|222x222pxYankin (yanki) na kankara na teku na Antarctic ya kai sabon ƙasa a cikin 2023."Charctic Interactive Sea Ice Graph / A Sea Ice Today Tool / Antarctic Sea Ice Extent". nsidc.org. National Snow and Ice Data Center (NSIDC), a part of CIRES at the University of Colorado Boulder. April 2025. Archived from the original on 26 April 2025. (Hover mouse over data traces to view individual data values.) Shafin ya nuna yadda ƙananan kankara na teku ya kasance a lokacin rani na Antarctic, wanda a wani lokaci a watan Fabrairun 2023 ya kasance kusan kashi 60% na matsakaicin 1981-2010.alt=|172x172pxRuwan kankara na teku na Antarctic yana raguwa zuwa mafi ƙarancinsa a kowace shekara a watan Fabrairu ko Maris; Ruwan kanjamau yana girma har sai ya kai iyakarsa a watan Satumba ko Oktoba.Halitta na kankara na teku na Antarctic da ke girma daga mafi ƙarancin yanayi zuwa mafi girman yanayi a lokacin kaka da hunturu (tsakanin Maris 21 da Satumba 19, 2014; alamun rubutu akan raye-raye). Ruwa na bazara ba a nuna shi ba.Rahoton 2" href="./IPCC_Fifth_Assessment_Report" id="mwgg" rel="mw:WikiLink" title="IPCC Fifth Assessment Report">IPCC AR5 ya kammala cewa "yana da matukar yiwuwar" cewa matsakaicin kankara na Antarctic na shekara-shekara ya karu da 1.2 zuwa 1.8% a kowace shekara goma, wanda shine 0.13 zuwa 0.20 miliyan km2 a kowace shekara, a lokacin 1979 zuwa 2012. : 7 IPCC AR5 kuma ya kammala cewa rashin bayanai ya hana ƙayyade yanayin a cikin jimlar girma ko taro na kankara na teku. Karin yankin kankara na teku mai yiwuwa yana da dalilai da yawa. Wadannan suna da alaƙa da canje-canje a cikin iskar yamma kudancin, waɗanda haɗuwa ne na bambancin yanayi da canjin tilasta daga iskar gas da rami na ozone. Iska tana fitar da kankara na teku, kuma binciken ƙira ya nuna cewa fadada kankara na ruwa da aka lura ya haifar da canje-canje a cikin saurin kankara na baybay. Wani direba mai yiwuwa shine narkewar kankara, wanda ke kara shigar da ruwa mai laushi zuwa teku; wannan yana kara da raunin teku mai laushi don haka yana rage ikon ruwan zafi don isa farfajiya. Wani binciken 2015 ya gano wannan tasirin a cikin samfuran yanayi don kwaikwayon canjin yanayi na gaba, wanda ya haifar da karuwar kankara a cikin watanni na hunturu. 

Canje-canje na baya-bayan nan a cikin tsarin iska, waɗanda ke da alaƙa da canje-canje na yanki a cikin yawan guguwa ta extratropical da anticyclones,  a kusa da Antarctica sun advected teku da ke arewacin arewa a wasu yankuna kuma ba har zuwa arewa a wasu ba.

Direbobin sararin samaniya da na teku na iya ba da gudummawa ga samar da yanayin yanki daban-daban a cikin yanayin kankara na teku na Antarctic. Misali, yanayin zafi a cikin yanayi da Kudancin Tekun sun karu a lokacin 1979-2004. Koyaya, kankara na teku yana girma da sauri fiye da yadda yake narkewa, saboda teku mai rauni. Don haka, wannan tsarin teku, a tsakanin wasu, yana ba da gudummawa ga karuwar samar da kankara, wanda zai iya haifar da karin kankara na teku. Kodayake lura da kauri yana da iyaka, ƙirar ta nuna cewa an lura da kankara zuwa yankunan bakin teku yana ba da ƙarin gudummawa don kauri na kankara a lokacin kaka da hunturu.

Abubuwan da aka lura da kaka da bazara a cikin yawan guguwa ta extratropical, anticyclones da tubalan, waɗanda ke da iko mai ƙarfi ta hanyar advection na zafin jiki, da kuma iko mai ƙarfi mai ƙarfi ta wurin kankara, a kan teku-kankara a lokacin haka kuma a lokacin da suka biyo baya kusan kusan ko'ina ne a kusa da Antarctica daidai da abin da aka lura, bambance-kankara.Schemm, Sebastian (25 June 2018). "Regional Trends in Weather Systems Help Explain Antarctic Sea Ice Trends". Geophysical Research Letters. 45 (14): 7165–7175. Bibcode:2018GeoRL..45.7165S. doi:10.1029/2018GL079109. hdl:20.500.11850/286394. S2CID 134805912. Sakamakon haka, ana zaton iskar da ke kusa da tsarin yanayi don bayyana manyan sassa na yanayin kankara na Antarctica.

Rahoton IPCC AR6 na 2021 ya tabbatar da karuwar yanayin da aka lura a cikin matsakaicin yankin kankara na Antarctic a cikin lokacin daga 1979 zuwa 2014 amma ya kimanta cewa akwai raguwa bayan 2014, tare da mafi ƙarancin kai a cikin 2017, da kuma ci gaba mai zuwa. Rahoton ya kammala cewa akwai "babban amincewa" cewa babu wani muhimmin yanayi a cikin tauraron dan adam da aka lura da yankin kankara na Antarctic daga 1979 zuwa 2020 a cikin hunturu da rani.

A farkon watan Janairun 2023, Cibiyar Bayanai ta Snow da Ice ta Kasa ta ba da rahoton cewa yawan kankara na teku na Antarctic ya tsaya a mafi ƙasƙanci a cikin rikodin tauraron dan adam na shekaru 45 - fiye da murabba'in kilomita 500,000 (193,000 murabba'i mil) a ƙasa da rikodin da ya gabata (2018), tare da hudu daga cikin shekaru biyar mafi ƙasƙantawa na rabin Disamba sun faru tun daga 2016. Fig. 5a

A watan Satumbar 2023, kankara ta teku ta Antarctic ta kai matsakaicin matsakaicin hunturu na murabba'in kilomita miliyan 16.96, kusan murabba'i kilomita miliyan daya kasa da rikodin da aka kafa a shekarar 1986.  Duk da yake ana bayar da rahoton karuwar net a wasu shekaru masu nisa ko karuwar kankara a wasu lokuta, wannan bai saba wa raguwar net da kankara na Antartic ya sha wahala shekaru da yawa ba.

 Sakamakon 
Kula da canje-canje a cikin kankara na teku yana da mahimmanci saboda wannan yana tasiri ga masu hankali da ke zaune a nan.

Canje-canje a cikin kankara na teku na Antarctic suna da mahimmanci saboda tasirin yanayi da yaduwar teku. Lokacin da kankara ta teku ta samo asali, tana ƙin gishiri (ruwan teku yana da gishiri amma kankara ta ruwa yana da kyau) don haka ana samar da ruwa mai gishiri wanda ke nutsewa kuma yana taka muhimmiyar rawa wajen samar da Ruwa na Ruwa na Antarctic.

 Tasirin Jirgin Ruwa 

Ƙarfin motsi na kankara yana da yawa; yana iya murkushe jiragen ruwa da aka kama a cikin kankara, kuma yana iyakance wuraren da jiragen ruwa zasu iya isa ƙasar, har ma a lokacin rani. Ana amfani da masu fashewar kankara, tashar kankara da tashar kan kankara don sauka da kayayyaki.

 Manazarta 

Rukuni:Shafuka masu fassarorin da ba'a duba ba