Polar night

Polar night wani yanayi ne na da ke faruwa a wasu yankuna na duniya inda rana ba ta bayyana a sararin samaniya gabaɗaya tsawon awanni ashirin da huɗu ko fiye. Wannan yanayi ba dare na yau da kullum ba ne, illa wani yanayi na musamman da ke faruwa kawai a yankunan da ke kusa da poles ɗin duniya, sakamakon tsarin juyawa da karkatar a kan bigirenta.
Ana rasa hasken rana a tsawon awanni 24 ko ma fiye a yayin da ake cikin yanayin polar nihgt.

Muhimmancin polar night a ilimin duniya yana ta’allaka ne ga yadda yake taimaka wa masana fahimtar alaƙar da ke tsakanin motsin duniya, zagayenta a kan rana, da rarrabuwar haske da duhu a saman doron ƙasa. Wannan yanayi yana da tasiri kai tsaye ga yanayin zafi, rayuwar mutane, dabbobi, da tsirrai a yankunan da abin ya shafa, kuma yana da muhimmiyar rawa a binciken ilimin taurari da na sauyin yanayi.

Polar night ya bambanta da sauran yanayin dare na al’ada domin a yawancin wurare na duniya, dare yana zuwa ne bayan faduwar rana, sannan rana ta sake fitowa bayan wasu sa’o’i. A polar night kuwa, ba a samun fitowar rana gabaɗaya, ba wai rana ta fadi kawai ba, har ma ba ta kai matsayin bayyana ko ɗan hango kanta a sararin sama ba, ko da na ɗan lokaci.

Ma’anar polar night a kimiyyance

A fahimtar masana kimiyya, polar night yanayi ne da ake bayyana shi ta fuskar ilimin taurari da ilimin ƙasa a matsayin lokacin da tsakiyar faifan rana (solar disk) bai ketare layin sararin sama (horizon) ko sau ɗaya a cikin awanni 24 ba. Wannan ma’anar tana dogara ne da ƙa’idojin lissafin motsawar rana da matsayin duniya a sararin samaniya, ba wai kawai ganin duhu da ido ba.

A ilimin taurari, ana kallon polar night a matsayin sakamakon karkatar bigiren juyawar duniya da kusan digiri 23.5, wanda ke sa wani ɓangare na duniya ya karkata daga rana a lokacin hunturu. A ilimin ƙasa kuwa, ana duban polar night ta fuskar yankuna, wato wuraren da ke cikin ko bayan iyakar Arctic Circle da Antarctic Circle, inda wannan yanayi ke iya faruwa a kowace shekara.

Polar night ya bambanta da dare na yau da kullum domin dare na al’ada yana faruwa ne sakamakon juyawar duniya kawai, inda kowanne wuri ke fuskantar rana sannan ya juya ya ba ta baya. A polar night kuwa, matsalar ba juyawa ba ce kaɗai, illa matsayin duniya gabaɗaya dangane da rana, wanda ke hana hasken rana kaiwa wani yanki gabaɗaya.

Maganar rana ba ta fito tsawon awanni 24, a kimiyyance ba tana nufin cewa duniya ta daina samun hasken rana gabaɗaya ba ne, sai dai tana nufin cewa rana ba ta kai matsayin fitowa a sararin samaniya ba. A wasu lokuta, ana iya samun ɗan haske mai rauni na twilight, amma hakan ba ya soke ma’anar polar night a matsayin cikakken rashin fitowar rana bisa ƙa’idojin kimiyya.

Karkatar duniya da asalin polar night

Karkatar Earth axial

Babban tushen samuwar polar night shi ne karkatar layin da duniya ke juyawa, wato abin da kimiyya ke kira axial tilt. Wannan layi ba ya tsaye daidai da layin zagayenta a sararin samaniya, sai dai yana karkata da kusan digiri 23.5. Wannan karkatarwa ita ce ke haifar da rabuwar yanayi tsakanin hunturu da rani, tare da bambancin tsawon dare da rana a sassa daban daban na duniya.

Zagayawar duniya

Yayin da duniya ke zagayawa a kewayen rana a duk shekara, wannan karkatarwa tana sa wani ɓangare na duniya ya karkata zuwa ga rana, yayin da wani ɓangaren kuma ke karkata daga gare ta. A lokacin da yankunan arewa ko kudu suka karkata daga rana, hasken ranar ba ya kaiwa wuraren da ke kusa da poles ɗin duniya. Idan karkatarwar ta kai wani mataki, rana ba ta iya ketare layin sararin samaniya gabaɗaya, abin da ke haifar da polar night.

Rawar da zagayawar duniya, wato orbit, ke takawa a nan ita ce tabbatar da cewa wannan yanayi ba na dindindin ba ne. Saboda duniya na zagaye rana, wuraren da suka shiga polar night a wani lokaci za su fita daga ciki a wani lokaci, sannan su fuskanci akasin haka, wato midnight sun. Don haka, polar night sakamako ne na haɗuwar karkatar layin da duniya ke zagayawa, ba wai wani abu na ba zata ko sauyin yanayi kai tsaye ba.

Yankunan da polar night ke faruwa

Polar night yana faruwa ne kawai a yankuna na musamman na duniya, musamman a waɗanda ke cikin ko bayan iyakokin arewa, da kudu. Waɗannan yankuna su ne layukan tunani na ilimin ƙasa da ke nuna iyakar inda rana za ta iya kasa fitowa tsawon awanni 24 a wasu lokutan shekara.

Arctic Circle da Antarctic Circle

A cikin Arctic Circle, polar night yana faruwa a lokacin hunturun arewacin duniya, yayin da a Antarctic Circle kuma yake faruwa a lokacin hunturun kudancin duniya. Tsawon lokacin polar night yana ƙaruwa ne yayin da ake ƙara matsowa kusa da poles ɗin duniya, daga kwana ɗaya kacal a kusa da Circle, zuwa watanni da dama a poles.

Bambanci tsakanin circle da pole

Bambanci tsakanin circle da pole yana da muhimmanci a fahimtar polar night. Circle iyaka ce ta ilimin ƙasa da ke nuna inda polar night zai iya faruwa, amma pole shi ne ainihin ƙarshen juyawar duniya. A da, polar night na iya ɗaukar kusan watanni shida a jere, inda rana ba ta bayyana ko sau ɗaya a tsawon wannan lokaci.

Wannan rarrabuwar yankuna na nuna cewa polar night ba yanayi ne da ke shafar duniya baki ɗaya ba, sai dai wani yanayi ne na musamman da ke faruwa a iyakantattun wurare sakamakon tsarin duniya da matsayinta a sararin samaniya.

Lokutan faruwar polar night

Lokacin faruwar polar night yana da alaƙa kai tsaye da rarrabuwar lokutan shekara, musamman lokacin hunturu. Wannan yanayi ba ya faruwa lokaci guda a duk duniya, sai dai yana bambanta tsakanin arewacin duniya da kudancin duniya, gwargwadon matsayin karkatar duniya a lokacin zagayenta a kewayen rana.

A arewacin duniya, polar night yana faruwa ne a lokacin hunturun arewa, wato daga kusan ƙarshen watan Satumba zuwa farkon watan Maris. A kudancin duniya kuma, polar night yana faruwa ne a lokacin hunturun kudu, wanda yawanci ya kasance daga kusan watan Maris zuwa Satumba. Wannan dangantaka tana nuna cewa polar night wani ɓangare ne na tsarin yanayi na duniya baki ɗaya.

Tsawon lokacin polar night

Tsawon lokacin polar night ba ya kasancewa iri ɗaya a ko’ina, yana bambanta gwargwadon nisan wuri daga iyakar circle zuwa poles ɗin duniya. A yankunan da ke kusa da Arctic Circle ko Antarctic Circle, polar night na iya kasancewa na kwana ɗaya kacal ko ‘yan kwanaki kaɗan. Yayin da ake matsowa kusa da poles ɗin duniya, tsawon polar night yana ƙaruwa daga kwanaki zuwa makonni. A poles ɗin duniya kansu, wato north pole da south pole, polar night na iya ɗaukar kusan watanni shida a jere. Dalilin wannan bambancin tsawon lokaci daga wuri zuwa wuri shi ne matsayin latitude.

Nau’o’in polar night

Civil polar night

Civil polar night shi ne nau’in da ya fi sauƙin duhu a cikin polar night. A wannan yanayi, rana tana kasancewa a ƙasa da sararin sama kaɗan, amma ba fiye da digiri shida ba. Duk da cewa rana ba ta fitowa, amma ana iya samun isasshen haske a wasu lokuta na rana, musamman a tsakiyar yini, wanda ke ba da damar ganin abubuwa ba tare da cikakken duhu ba.

Nautical polar night

Nautical polar night yana faruwa ne idan rana ta sauka tsakanin digiri shida zuwa digiri goma sha biyu a ƙasa da sararin samaniya. A wannan yanayi, duhu yana ƙaruwa sosai, kuma sararin samaniya yana fara rasa hasken da ke ba da damar bambance abubuwa a nesa. An fi kiran wannan yanayi da “nautical” ne saboda yana da tasiri kai tsaye ga masu amfani da taurari wajen gano hanya a teku.

Astronomical polar night

Astronomical polar night shi ne nau’in da ya fi tsanani. A nan, rana tana ƙasa da digiri goma sha takwas a ƙasa da sararin samaniya. A wannan mataki, ana samun kusan cikakken duhu a sararin samaniya, sai dai hasken wata, taurari, ko wasu abubuwan haske na halitta. Wannan nau’i ne da ya fi dacewa ga binciken taurari.

Bambancin da ke tsakanin waɗannan nau’o’i ya ta’allaka ne gabaɗaya a kan matsayin rana a ƙasa da sararin samaniya, ba wai tsawon lokacin polar night kawai ba.

Haske a lokacin polar night

Duk da sunan da ake kiran polar night da shi, wannan yanayi ba lallai ba ne ya zama duhu tsantsa a kowane lokaci. A wasu lokuta, ana samun wani nau’in haske mai rauni da ake kira twilight. Twilight yana da nau’o’i da dama: civil twilight, nautical twilight, da astronomical twilight, waɗanda suka dace da nau’o’in polar night da aka bayyana a baya.

Dalilin da ya sa ba a samun duhu tsantsa a kodayaushe shi ne yanayin watsuwar haske a cikin sararin duniya. Haske daga rana, ko da yana nesa da sararin samaniya na yankin, yana iya watsewa a cikin iska, ya haifar da ɗan haske mai rauni. Haka kuma, hasken wata, taurari, da kuma hasken dusar ƙanƙara na iya ƙara rage tsananin duhu a wasu lokuta.

Yanayin haske a sararin samaniya a lokacin polar night yana da muhimmanci a fannin binciken kimiyya, musamman a ilimin taurari.

Polar night da yanayin zafi

Polar night yana da tasiri kai tsaye ga raguwar yanayin zafi, domin rashin fitowar rana na tsawon lokaci yana hana doron ƙasa samun makamashin zafi daga hasken rana. Dangantakar polar night da yanayin ƙanƙara yana bayyana ne ta hanyar tsawaita lokacin da ƙanƙara ke taruwa da kuma jinkirin narkewarta. Polar night yana kuma shafar yanayin iska da samuwar guguwar sanyi.

Polar night da rayuwar ɗan Adam

Duk da tsananin yanayinsa, mutane sun daɗe suna rayuwa a yankunan da polar night ke faruwa. Polar night yana da tasiri ga lafiyar mutum, musamman ta fuskar barci, damuwa, da yanayin tunani. Domin daidaita rayuwa, mutane suna amfani da fitilu a madadin hasken rana, tsara ayyukansu bisa tsari mai tsauri, da kuma al’adu da ayyukan zamantakewa domin rage tasirin duhun.

Polar night da halittun dabbobi

Dabbobi da ke zaune a yankunan polar night suna da ƙwarewa ta musamman wajen rayuwa ba tare da hasken rana na tsawon lokaci ba. A lokacin polar night, halayen dabbobi na iya sauyawa sosai, wasu na rage yawo, wasu na sauya tsarin neman abinci, yayin da wasu ke sauya yanayin barci. Misalan dabbobin nan sun haɗa da ɓeraye, kifayen sanyi, da wasu tsuntsaye masu iya jure matsanancin yanayi.

Polar night da tsirrai

Polar night yana da ƙalubale ga tsirrai domin yawancin tsirrai na dogara da hasken rana domin yin photosynthesis. Sai dai, tsirran yankunan polar night sun daidaita kansu ta hanyoyi na musamman, wasu suna shiga yanayin dakatawa, wasu kuma suna amfani da makamashin da suka tara a lokacin rani. Wannan daidaituwar ta nuna yadda halittu ke iya jure matsanancin yanayi.

Matsaloli da kalubalen polar night

Polar night yana haifar da matsaloli a fannin sufuri, inda rashin hasken rana ke rage gani, haifar da haɗari, da ƙara tsada wajen gudanar da ayyuka. Haka kuma, yana shafar lafiyar mutane, inda rashin hasken rana ke jawo matsalolin barci, damuwa, ƙarancin vitamin D, da Seasonal Affective Disorder (SAD).

Tasirin polar night ga tattalin arziki yana bayyana ne a ayyuka da masana’antu da harkokin noma da kiwo, yayin da yawon shaƙatawa da bincike na iya tsayawa ko raguwa sakamakon yanayi mai tsanani.

Manazarta

Brown, A. (2019). Twilight phenomena in polar regions. Polar Research Journal, 8(2), 101–119.

NASA. (2022, March 15). Earth’s axial tilt and its effects on seasons.

Smith, J., & Thompson, L. (2020). Polar night and its ecological impacts. Journal of Arctic Studies, 12(3), 45–62.

Williams, R., Chen, Y., & Lopez, M. (2021). Human adaptation to extreme photoperiods: Case studies from the Arctic and Antarctic. International Journal of Environmental Science, 15(1), 77–95.

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