da Milankovitch hawan keke ya dogara ne akan gaskiyar cewa canje-canje na orbital suna da alhakin lokutan glacial da interglacial. Yanayin ya bambanta bisa ga sigogi uku na asali waɗanda ke canza motsin duniya. Mutane da yawa suna danganta canjin yanayi zuwa hawan Milankovitch, amma wannan ba haka bane.
A saboda wannan dalili, za mu keɓe wannan labarin don gaya muku yadda zagayowar Milankovitch ke aiki da kuma yadda mahimmancin yanayin yanayi yake ga duniyarmu.
Menene hawan keke Milankovitch?
Muna fuskantar ɗaya daga cikin mahimman samfuran kimiyya. Kafin zuwan zagayowar Milankovitch a cikin karni na XNUMX, abubuwan da suka kawo cikas ga canjin yanayi a duniya ba a san su sosai a cikin al'ummar kimiyya ba. Masu bincike kamar Joseph Adhemar ko James Croll suna neman amsoshi daga dusar ƙanƙara ta tsakiyar karni na sha tara zuwa lokutan da ake fama da matsanancin sauyin yanayi. An yi watsi da littattafansa da bincikensa har sai masanin lissafin Serbia Milankovic ya dawo da su kuma ya fara aiki a kan ka'idar da ta canza komai.
Yanzu mun san yadda mutane ke yin tasiri ga sauyin yanayi, amma kuma yana da mahimmanci a lura cewa ba shi kaɗai ba ne. Hakanan ana iya bayyana canjin yanayi a duniya ta hanyar tasirin abubuwan da ke waje zuwa duniya. Kewayoyin Milankovitch sun bayyana yadda sauye-sauyen yanayi ke ba da gudummawa ga canjin yanayi a duniya.
Milankovitch sigogi na sake zagayowar
Yanayi yana da alaƙa da canje-canje na orbital. Milankovitch ya yi imanin cewa hasken rana bai isa ya canza yanayin duniya gaba daya ba. Koyaya, canje-canje a cikin kewayar duniya yana yiwuwa. Ga yadda aka ayyana su:
- Glaciation: high eccentricity, low karkata, da kuma manyan nisa tsakanin Duniya da Rana haifar da kadan bambanci tsakanin yanayi.
- Interglacials: Ƙarƙashin ƙaƙƙarfan yanayi, babban karkata, da ɗan gajeren nisa tsakanin Duniya da Rana, yana haifar da yanayi daban-daban.
Bisa ga ka'idar Milankovitch, tana canza motsi na fassarar da jujjuyawar duniya bisa manyan sigogi guda uku:
- Da eccentricity na kewayawa. Ya dogara ne akan yadda miƙewar ellipse yake. Idan kewayen duniya ya fi elliptical, eccentricity ya fi girma, kuma akasin haka idan ya fi madauwari. Wannan bambancin zai iya yin bambanci 1% zuwa 11% a cikin adadin hasken rana da duniya ke karɓa.
- Ƙaunar juna. Waɗannan canje-canje ne a kusurwar axis na duniya. Dip yana canzawa tsakanin 21,6º da 24,5º kowane shekaru 40.000.
- Precession Muna magana ne game da yin axis na juyawa sabanin alkiblar juyawa. Tasirinsa akan yanayin shine sakamakon canza matsayi na dangi na solstices da equinoxes.
Masanin lissafi na Serbia yana fatan nunawa a farkon karni na XNUMX cewa, baya ga tasirin ɗan adam, muna bukatar mu fahimci yadda duniyarmu ta kasance da kuma yadda canje-canje na orbital ke iya canza yanayi.
Duk da haka, rawar da muke takawa a cikin sauyin yanayi ba shi da tabbas. Dan Adam yana canza dabi'a na al'ada na al'ada na duniya da kuma yanayi, don haka dole ne mu fara samun hali mai dorewa wanda ke kare muhalli.
sakamakon yanayi
A halin yanzu, saboda duniya ta ratsa perihelion a lokacin hunturu na arewaci (Janairu), ɗan gajeren nisa daga rana yana ɗaukar sanyin hunturu a wannan yankin. Hakazalika, tun da Duniya ta kasance a aphelion a lokacin rani na arewacin hemisphere (Yuli), a nisa mafi girma daga rana yana ɗaukar zafi lokacin rani. Watau, tsarin da duniya ke kewaya rana a halin yanzu yana taimakawa rage bambance-bambancen yanayin zafi na yanayi a yankin arewaci.
Akasin haka, an kara jaddada bambance-bambancen yanayi na yanayi a yankin kudu. Duk da haka, tun da lokacin rani ya fi tsayi a arewa kuma lokacin sanyi ya fi guntu lokacin da rana ta fi nisa daga duniya, bambanci a cikin tafkin makamashi na yanayi da aka samu bai kai haka ba.
Ka'idoji
Ka'idodin gargajiya na paleoclimate suna ba da shawarar cewa glacialization da lalata ya fara ne a manyan latitudes a arewa maso yammacin duniya kuma ya bazu zuwa sauran duniya. A cewar Milankovitch, ana buƙatar lokacin rani mai sanyi a cikin manyan latitudes na arewacin helkwatar don rage narkewar lokacin rani da ƙyale dusar ƙanƙara. Kaka ya zo da hunturu kafin.
Domin wannan tarin dusar ƙanƙara da ƙanƙara ya faru, dole ne insolation ɗin rani ya yi ƙasa kaɗan, wanda ke faruwa lokacin da bazara ta arewa ta zo daidai da aphelion. Wannan ya faru kimanin shekaru 22.000 da suka wuce, lokacin da mafi girman ci gaban glacial ya faru (shi ma yana faruwa a yanzu, amma tare da tasiri mafi girma fiye da yau saboda girman girman sararin samaniya). Akasin haka, asarar ƙanƙara na nahiyar yana da kyau lokacin da manyan latitudes ke da babban yanayin bazara da ƙarancin hunturu, yana haifar da lokacin zafi mai zafi (ƙarin narkewa) da lokacin sanyi (ƙasasshen dusar ƙanƙara).
Wannan yanayin ya kai kimanin shekaru 11.000 da suka wuce.. Matsayin perihelion da aphelion yana canza yanayin rarraba makamashin hasken rana kuma yana iya yin tasiri mai mahimmanci akan tsarin deglacial na ƙarshe.
Duk da haka, dole ne a yi la'akari da cewa ƙarfin radiation a lokacin rani ya bambanta da tsawon lokacin rani. Wannan ya faru ne saboda dokar Kepler ta biyu, wadda ta bayyana cewa motsin duniya yana da sauri yayin da yake wucewa ta hanyar perihelion. Wannan shine diddigen Achilles na ka'idar cewa gabaci ya mamaye zamanin Ice. Dip yana da mahimmanci fiye da abin da aka rigaya da kuma abubuwan da suka dace a lokacin da ake la'akari da mahimmancin zafin rana a lokacin rani (ko mafi kyau duk da haka, a lokacin kwanakin da rigar arewa ta narke). Zagayowar precession na equinox na iya zama mafi yanke hukunci a cikin yanayi na wurare masu zafi fiye da a yankunan polar, inda karkatar da axial ya bayyana yana taka rawar gani.
Ina fatan cewa tare da wannan bayanin za ku iya ƙarin koyo game da hawan keke Milankovich da yadda suke shafar yanayin.