Kamar yadda muka sani, glaciers Manyan kankara ne, masu kauri kuma masu ɗimbin yawa waɗanda ke samarwa a bayan ƙasa sakamakon haɗuwa, haɗuwa da dusar kankara bayan shekaru da aka kwashe. A yau za mu yi magana game da wani bangare mai ban sha'awa na kankara. Game da shi circier circus. Muhimmancin kankara yana ƙara zama mai dacewa a cikin yanayin canjin yanayi wanda muka sami kanmu a ciki.
A cikin wannan labarin zamuyi bayanin abin da circus na glacial yake da mahimmancin sa.
Dynamics na kankara
Don fahimtar menene ma'anar glacial cirque, dole ne mu fara sanin yadda ake yin kankara. Lokacin da yawan ruwa da ke ɗebowa a lokacin rani ya wuce na dusar ƙanƙarar shekara-shekara aikin ya fara narkewa. Idan kankara ta samu ya zama dole a sami daidaiton adadin dusar da aka sanya a saman duniya sabanin yawan dusar ƙanƙan da ke narke ko ƙazantar da ruwa.
Akwai nau'ikan kankara iri-iri a ko'ina cikin duniya. Tsakanin kowane nau'in kankara, ana iya bambanta siffofi daban-daban. Misali, Akwai glaciers mai kwari, alkuki, siffofin filin kankara, da dai sauransu Yanayin canjin yanayin da muke samu shima yana tantance abubuwan idan yakai ga ganin sikirin kankara. Waɗannan sharuɗɗan na iya zama na wurare masu zafi, yanayi, ko iyakacin duniya. Yanayin zafi yana tasiri yawan dusar kankara da ke taruwa ko narkewa. Dogaro da matsakaicin yanayin yanayin zafi da muke samu a cikin yanki mai ƙarancin sanyi, ƙila mu sami tarin dusar ƙanƙara da kuma matsi fiye da idan yanayin zafi ya canza fiye da haka.
A halin yanzu, 10% na saman duniyarmu an rufe shi da glaciers. A zamanin mulkin kasa an rufe shi da kashi 30%. Ana iya cewa yanayin yanayin ƙasa ne wanda ke tara mafi yawan ruwa mai ɗanɗano a duniya. Saboda haka haɗarin abin da yake gabatowa ko, sabili da haka, hauhawar yanayin teku.
Kashi 84% na dukkan yankin dake kankara a Antarctica yake, yayin da sauran ya kasu kashi biyu zuwa Greenland da sauran yankuna masu sanyi na duniya.
Menene circus circa?
Yanzu da mun tuna yadda tasirin dusar kankara ke aiki, za mu iya shiga cikin madaidaicin gilashi. A circus circus wani circus glacier shine wani irin kwaran dutse mai siffar zana zagaye Hakan na faruwa ne ta hanyar zugarwa ko shafawa ko kankara tare da yarjejeniya ko cikin tarawa ko yankin ciyarwa. Yankin tarawar kankara shine bangaren da adadin dusar kankara da aka ajiye ya fi wanda yake narkewa yawa. A gefe guda, muna da yankin abrasion inda ƙimar narkewa ya fi yawan tarin kuɗi.
Galibi mai ƙyalƙyali yana cikin sifar amphitheater ko kujera tare da ƙarin bayyane gefuna ko tare da tsaunuka masu tsaye kewaye da shi. Cirque na glacial galibi yana da sassa biyu waɗanda za'a iya rarrabe su da sauƙi. Muna da bangaren da aka raba shi da wani kira da ake kira rimaya wanda ke wucewa ko kwance: a nan zamu sami ɓangaren ƙananan, wanda shine inda ƙarin dusar ƙanƙara da kankara ke tarawa. Bangaren na sama, a gefe guda, yana da tudu mafi girma kuma kankara ta fi matsewa saboda ƙananan zafin jiki.
Hakanan zamu iya samun yankin ɓacewa a cikin circuque. Wannan yankin shine wurin da ake yin narkewa, bayani dalla-dalla da rabe-raben dusar kankara yayin shiga teku.
Halaye na glacier cirque
Kodayake akwai nau'ikan da'ira iri daban-daban, dukansu ana yin su ne ta hanyar samun wasu siffofi na ɗanɗano wanda zai ba mu damar rarrabe na waɗanda ke marabar tarbar kogunan tsaunuka. Daga cikin manyan halayen muna da ganuwarta ta sama. Suna nan sama da bergschrund na tsohuwar kankara. Waɗannan bangon ba a iyakance su ba ko kuma lalata su ta hanyar dusar kankara. Gangarensa suna da tsayi sosai kuma yanayinsa ba daidai bane saboda faduwar kankara wadanda zasu manne da dutsen.
A gefe guda, muna da ƙasan girar glacial. Tana da rami ƙasa da yawa fiye da ganuwar. A wannan bangon zamu iya samun duwatsu masu laka iri-iri waɗanda tasirin yanayin samaniya ya lalata su. Wasu lokuta, zamu iya samun igiyoyin moraine waɗanda suke layi ɗaya a cikin shugabancin gangaren. Bottomasan circus na iya zama mai siffar kwando ko a kwance. Bugu da ari, Dogaro da fasalin su, zasu iya samun lagoons ɗaya ko fiye.
A cikin da'irar da ke cikin sifar amphitheater, ɓangaren giciye yana da sashi mai fasali na U. A ƙasan gefen gefen gefen da'irar za mu ga yadda ake taɓar da gangaren alamar farkon kwarin glacial.
Athough ba alama, Berry yana da mahimmancin gaske a cikin girar glacial. Tsaguwa ce ta kwance wacce ke samarwa a cikin kankara a gefen fatar walƙiya. Wannan tsagwaron shine ke da alhakin raba tsayayyen kankarar da ke makale a kan duwatsu daga kankarar da ke motsa kankarar kanta.
Berry tana buɗewa kuma tana fallasa dutsen da yake tsayi a farkon bazara. Wannan saboda yanayin zafi mai yawa da farkon narkewar kankara. Dutse yana fuskantar yanayi na rana da na dare a cikin yanayin zafin jiki. Wadannan sake zagayowar na daskarewa da narkewa, a karkashin aikin sanyi, suna sa dutsen ya rabu a hankali kuma ya sa duwatsun sama su ruguje. Wannan shine yadda duwatsu ke ɗaukar sifofin da aka yanke da marasa tsari.
Wadannan canjin daskararren-narkewar ana rudasu ta hanyar canjin yanayi. Theungiyar narkewa tana ƙaruwa fiye da adadin hazo a cikin yanayin dusar ƙanƙara wanda ke ba da damar tarawa sanar da kankara.
Ina fatan cewa tare da wannan bayanin zaku iya ƙarin koyo game da wasan circa.