Bayani game da Da'irar Arctic da Antarctic
Da'irar Arctic da Da'irar Antarctic layuka ne guda biyu na tunani waɗanda galibi ake ambata a cikin ilimin ƙasa, ilmin taurari, da kimiyyar yanayi. Ba "layuka" ba ne da ake gani a saman Duniya, amma iyakokin ƙasa ne waɗanda ke nuna yankuna tare da abubuwan da suka bambanta na halitta, musamman tsawon dare da rana. Fahimtar waɗannan da'irori yana taimaka mana mu fahimci dalilin da yasa wasu yankuna ke fuskantar kwanaki ba tare da faɗuwar rana ba, ko kuma, akasin haka, tsawon dare ba tare da hasken rana ba.
Menene Da'irar Arctic da Da'irar Antarctic?
A taƙaice dai, Arctic Circle layin latitude ne a Arewacin Hemisphere, yayin da Antarctic Circle yake a Kudancin Hemisphere. Dukansu suna a kusan latitude 66,5° daga equator:
– Da'irar Arctic tana kusa da 66,5° N (Arewa Latitude).
– Da'irar Antarctic tana kusa da 66,5° Kudancin Latitude.
Wannan adadi na 66,5° yana da alaƙa kai tsaye da karkacewar axis na juyawar Duniya. Duniya tana karkata kimanin 23,5° idan aka kwatanta da matakin zagayenta da ke kewaye da Rana. Saboda haka, wasu yankuna suna samun kusan hasken rana akai-akai a wasu lokutan shekara, yayin da wasu kuma ba sa samun ko ɗaya kwata-kwata.
Me yasa ake kiransa "da'ira"?
Ana kiransa "da'ira" domin idan ka zana layin latitude a kusa da Duniya, zai samar da cikakken da'ira. Wannan layin yana daidai da equator, kamar sauran layukan latitude. Amma abin da ya sa ya zama na musamman shine aikinsa a matsayin iyaka ta sararin samaniya da yanayi, ba kawai alamar matsayi ba.
Babban abin mamaki: Rana ta tsakar dare da dare mai faɗi
Abubuwa biyu mafi shahara da ke faruwa a yankunan da ke sama da Arctic Circle ko ƙasa da Antarctic Circle sune:
1. Tsakar dare Lahadi (Tsakar dare Lahadi)
A wasu lokutan, musamman a lokacin bazara a kowace duniya, Rana ba ta taɓa faɗuwa gaba ɗaya a ƙarƙashin sararin sama na tsawon awanni 24 ko fiye. Sakamakon haka, duk da cewa "dare" ne a zahiri, sararin sama yana da haske.
2. Daren Polar
Sabanin haka, a lokacin hunturu, rana ba ta bayyana sama da sararin sama na tsawon awanni 24 ko fiye. Yankunan da ke fuskantar duhun dare suna fuskantar duhu mai tsawo, kodayake yawanci akwai ɗan duhu a wasu lokutan, ya danganta da wurin da yanayin yanayi.
A yankunan da ke kusa da da'irar (66,5°), wannan lamari yana faruwa kusan sau ɗaya a shekara. Duk da haka, yayin da mutum ke kusantar sandunan (90° N ga Arewacin Duniya da 90° S ga Kudancin Duniya), tsawon lokacin "rana ta tsakar dare," ko "daren polar," yana ƙaruwa, har ma watanni masu ɗorewa.
Bambance-bambance tsakanin yankunan Arctic da Antarctic
Duk da cewa dukkansu suna da taken "sandunan ƙasa", Arctic da Antarctic sun bambanta sosai.
1. Arctic: teku da ƙasa ke kewaye da shi
Yankin Arctic a zahiri Tekun Arctic ne, wanda aka fi rufe shi da kankara (musamman a lokacin hunturu), kuma yana kewaye da nahiyoyi kamar Arewacin Amurka, Turai, da Asiya. Yankin Arctic gida ne ga al'ummomin ɗan adam da yawa, gami da mutanen asali da ƙananan garuruwa zuwa matsakaici a ƙasashe kamar Kanada, Norway, Rasha, da Alaska (Amurka).
Saboda yankin Arctic teku ne, yawancin ƙanƙararsa tana shawagi ne a kan teku. Wannan ƙanƙara tana da matuƙar saurin kamuwa da canje-canje a yanayin zafi da kwararar ruwa, don haka tasirin ɗumamar yanayi a yankin Arctic yana bayyana musamman ta hanyar raguwar girman ƙanƙarar teku.
2. Antarctica: nahiyar da ke kewaye da tekuna
Sabanin haka, Antarctica nahiyar ce da ke cike da kauri mai kauri na kankara, kewaye da Tekun Kudancin. Antarctica ba ta da yawan jama'a na dindindin; mutanen da ke zaune a wurin galibi masana kimiyya ne da ma'aikatan tallafi a tashoshin bincike.
Kankarar da ke Antarctica ta samo asali ne daga zanen kankara na ƙasa. Idan zanen kankara na ƙasa ya narke ya kuma kwarara zuwa cikin teku, tasirin da zai iya yi wa hauhawar matakin teku a duniya zai iya zama mafi girma fiye da canje-canjen kankara mai iyo a teku.
Me yasa wannan layin yake canzawa?
A fasaha, matsayin da'irar Arctic da Antarctic ba su "daidai" ba tsawon dubban shekaru. Wannan ya faru ne saboda ƙananan canje-canje a cikin karkatar da axial na Duniya (ƙwanƙwasa), wanda ke canzawa a hankali a kan zagayowar taurari na dogon lokaci. Lokacin da karkatar Duniya ta canza kaɗan, latitudes da ke fuskantar zagayowar rana/dare na awanni 24 suma suna canzawa kaɗan.
Duk da cewa canje-canjen ba su da yawa a sikelin rayuwar ɗan adam, suna da mahimmanci a kimiyya don fahimtar yanayi da yanayin sararin samaniya a kan sikelin dogon lokaci.
Tasiri ga yanayi da rayuwa
Yankunan da ke kewaye da waɗannan da'irori biyu suna da yanayi mai tsauri: hunturu mai tsawo, sanyi da kuma lokacin rani mai tsawo wanda zai iya zama sanyi ko dumi sosai a wurare (musamman a yankin Arctic a wasu yankunan bakin teku).
Tsarin Yanayi na Arctic
Yankin Arctic yana da tsaunukan tundra, gansakuka, ƙananan bishiyoyi, da namun daji kamar beyar polar, dila na Arctic, caribou, da tsuntsayen da ke ƙaura daban-daban. Rayuwar ɗan adam a yankin Arctic ta kuma saba da waɗannan yanayi ta hanyar farauta, kamun kifi, da kuma tsarin mafaka da ya dace da yanayin sanyi.
Tsarin Yanayi na Antarctic
Antarctica ta fi tsanani. Rayuwa a ƙasa tana da iyaka, amma teku da ke kewaye tana da wadata a cikin rayuwa, ciki har da krill (ƙananan jatan lande), seal, whales, da penguins. Sarkar abinci a wannan yanki ta dogara ne sosai kan yawan amfanin teku na yanayi da kuma samuwar ƙanƙarar teku.
Muhimmancin rawar da ake takawa a fannin kimiyya
Yankunan Arctic da Antarctic suna aiki a matsayin "dakunan gwaje-gwaje na halitta" don nazarin sauyin yanayi. Masana kimiyya sun lura:
- canje-canje a cikin girman kankara na teku a kowane lokaci,
- narkewar dusar ƙanƙara da zanen kankara,
- yanayin iska da kwararar ruwa a teku,
- da kuma sinadaran yanayi (misali iskar ozone da iskar gas mai dumama yanayi).
Antarctica kuma ta shahara wajen gano da kuma sa ido kan ramin ozone a cikin stratosphere, wanda ke taimaka wa duniya fahimtar tasirin wasu sinadarai (kamar CFCs) akan sararin samaniya. A halin yanzu, Arctic alama ce mai sauri ta ɗumamar yanayi saboda yankunan polar suna ɗumama da sauri fiye da matsakaicin duniya, wani lamari da ake kira ƙara girman Arctic.
Kammalawa
Da'irar Arctic da Da'irar Antarctic suna da muhimman iyakokin latitude waɗanda suka shafi karkatawar axial na Duniya da kewayar Rana. Dukansu suna wakiltar yankunan da ake iya fuskantar rana ta tsakar dare da dare na polar, abubuwan da ba a cika ganinsu a wurare masu zafi ko wurare masu zafi ba. Duk da cewa suna da kama da juna a ra'ayi, Arctic da Antarctic sun bambanta sosai dangane da yanayin ƙasa, yanayin halittu, da kasancewar ɗan adam. Fahimtar waɗannan da'irori biyu ba wai kawai suna ƙara fahimtar yanayin ƙasa ba ne, har ma suna ƙarfafa fahimtarmu game da yanayin yanayi na duniya da makomar muhallin Duniya.
Idan kuna so, zan iya daidaita wannan labarin zuwa salon "wanda ɗalibai suka shahara", sigar "kimiyya mai nassoshi", ko kuma ƙara sassa na musamman kamar misalan ƙasashen da Arctic Circle ta haɗu da su da kuma muhimman tashoshin bincike a Antarctica.
