Matsalar shekaru 100,000

**Matsalar shekaru 100,000** (kuma matsala ta 100 ky ko matsala ta 100 ka) na Ka'idar Milankovitch na tilastawar orbital tana nufin bambanci tsakanin rikodin zafin jiki da aka sake gina shi da adadin hasken rana mai shigowa, ko insolation a cikin shekaru 800,000 da suka gabata. Saboda bambance-bambance a cikin yanayi duniya, adadin insolation ya bambanta da lokutan kusan shekaru 21,000, 40,000, 100,000, da 400,000. Bambance-bambance a cikin adadin abubuwan da suka faru na hasken rana suna motsa canje-canje a cikin yanayin Duniya, kuma an gane su a matsayin mahimmin abu a lokacin farawa da ƙarewar glaciations.

Duk da yake akwai sake zagayowar Milankovitch a cikin kewayon shekaru 100,000, wanda ke da alaƙa da ƙarancin duniya, gudummawar da ya bayar ga bambancin insolation ya fi ƙanƙanta fiye da waɗanda ke cikin precession da obliquity. Matsalar shekaru 100,000 tana nufin rashin bayyane game da lokacin da ake amfani da shi a kusan shekaru 100,000 a cikin shekaru miliyan da suka gabata, amma ba kafin haka ba, lokacin da mafi yawan lokacin ya dace da shekaru 41,000. Canjin da ba a bayyana ba tsakanin gwamnatocin lokaci guda biyu an san shi da Canjin Tsakiyar Pleistocene, wanda aka tsara zuwa kimanin shekaru 800,000 da suka gabata.

Matsalar da ke da alaƙa da shekaru 400,000 tana nufin rashin shekarun shekaru 400,000 saboda ƙarancin ƙwayoyin cuta a cikin rikodin zafin jiki na ƙasa a cikin shekaru miliyan 1.2 da suka gabata.&nbsp;

Canjin lokaci daga shekaru 41,000 zuwa shekaru 100,000 yanzu ana iya sake shi a cikin ƙididdigar ƙididdiga waɗanda suka haɗa da raguwar yanayin carbon dioxide da cirewar regolith, kamar yadda aka bayyana dalla-dalla a cikin labarin Mid-Pleistocene Transition . 

## Sanar da sake zagayowar shekaru 100,000

Za'a iya sake ginawa rikodin zafin jiki na ƙasa daga shaidar sedimentary. Wataƙila mafi amfani paleotemperature nuna alamar yanayi na baya shine raguwa isotopes na oxygen, wanda aka nuna δ18O. Wannan raguwa ana sarrafa shi galibi ta hanyar adadin ruwan da aka kulle a cikin kankara da kuma cikakkiyar zafin jiki na duniya kuma ya ba da izinin gina Matakan isotope na ruwa.

A ƙarshen shekarun 1990s, ana samun bayanan &#x3B4; na iska (a cikin ƙarancin kankara na Vostok) da kuma ruwan teku kuma an kwatanta su da ƙididdigar insolation, wanda ya kamata ya shafi duka zafin jiki da ƙarar kankara. Kamar yadda Shackleton (2000) ya bayyana, rikodin zurfin teku na δ18O "ya mamaye ta hanyar cyclicity na shekaru 100,000 wanda aka fassara shi a duniya a matsayin babban yanayin kankara". Shackleton (2000) ya daidaita sikelin lokaci na rikodin kankara na Vostok δ18O don dacewa da tilastawar da aka ɗauka kuma ya yi amfani da bincike na bakan gizo don ganowa da cire ɓangaren rikodin wanda a cikin wannan fassarar za'a iya danganta shi da amsawar layi (daidai daidai) ga tilastawar orbital. Sakamakon siginar (sauran), idan aka kwatanta da ragowar daga rikodin isotope na ruwa, an yi amfani da shi don kimanta yawan siginar da ke tattare da ƙarar kankara, tare da sauran (wanda ya yi ƙoƙari ya ba da damar tasirin Dole) ana danganta su da canje-canjen zafin jiki a cikin ruwa mai zurfi.

An gano bangaren shekaru 100,000 na bambancin girman kankara don daidaita rikodin matakin teku bisa ga ƙaddamar da shekarun murjani, da kuma jinkirta ƙarancin ƙarancin ta hanyar dubban shekaru, kamar yadda za a sa ran idan ƙarancin ƙwaƙwalwar ita ce hanyar tafiya. "Jumpings" masu ƙarfi a cikin rikodin sun bayyana a deglaciations, kodayake shekarun 100,000 ba shine mafi ƙarfin lokaci a cikin wannan rikodin "tsarkakewa" na kankara ba.

## Tunanin da za a iya bayyana matsalar

Kamar yadda shekarun 100,000 kawai ke mamaye yanayin na shekaru miliyoyin da suka gabata, babu isasshen bayani don raba sassan sassan da ke cikin ƙarancin ta amfani da bincike na bakan gizo, yana sa amintaccen ganowa na mahimman abubuwan da ke faruwa na dogon lokaci ya fi wuya, kodayake nazarin bakan gizo na rikodin paleoclimate da yawa, kamar Lisiecki da Raymo na ƙwayoyin ruwa [1] da rikodin isotopic na James Zachos, yana taimakawa wajen sanya shekaru miliyan da suka gabata a cikin yanayin dogon lokaci. Saboda haka har yanzu babu wata hujja mai kyau game da tsarin da ke da alhakin 100 ka - amma akwai ra'ayoyi masu inganci da yawa.

## Manazarta