Daraasad qotodheer oo ay hormuud ka ahaayeen cilmi-baarayaasha Jaamacadda Arizona ayaa laga yaabaa inay xalliyeen laba sir oo in badan ka yaabiyay khubarada cimiladu paleo-Climate: Xagee bay ka yimaadeen go'yaal baraf ah oo dhacay waqtigii barafka ee ugu dambeeyay in ka badan 100,000 oo sano ka hor, sideese u koraan si degdeg ah?
Fahamka waxa dhaqaajiya wareegyada glacial-glacial-ka-hormarka xilliyeed iyo dib-u-noqoshada xaashida barafka ee Hemisphere-waqooyi-ma aha wax fudud, cilmi-baarayaashuna waxay u hureen dadaal la taaban karo si ay u sharxaan balaadhinta iyo dhimista barafka waaweyn kumanaan sano. Daraasadan oo lagu daabacay joornaalka Nature Geoscience, ayaa soo jeedinaysa sharaxaad ku saabsan balaadhinta degdega ah ee xaashida barafka ee daboolay in badan oo ka mid ah Hemisphere Northern Hemisphere intii lagu jiray xilligii barafka ee ugu dambeeyay, natiijooyinka ayaa sidoo kale lagu dabaqi karaa xilliyada glacial ee taariikhda Dunida oo dhan.
Qiyaastii 100,000 oo sano ka hor, markii mammoths ay ku wareegeen dhulka, cimilo-badeedka Waqooyiga Hemisphere ayaa ku dhacay baraf qoto dheer taas oo u oggolaanaysa in baraf weyn ay sameeyaan. Muddo ku dhow 10,000 oo sano, glaciers buuraleyda ah ayaa koray oo sameeyay baraf waaweyn oo daboolaya inta badan Kanada, Siberiya iyo waqooyiga Yurub.
In kasta oo si weyn loo aqbalay in xilli-xilliyeedka “gariir” ee wareegga dhulka ee qorraxda ku wareegsan uu qabo qaboojin ku yimid Waqooyiga Hemisphere xagaaga taas oo sababtay bilawga glaciation baahsan, saynisyahannadu waxay ku dhibtoonayeen inay sharaxaan baraf baraf ah oo daboolaya inta badan Scandinavian iyo waqooyiga Yurub. halkaasoo heerkulku aad u khafiifsan yahay.
Si ka duwan qabowga Kanadiyaanka Arctic Archipelago halkaas oo baraf si sahal ah u sameeyo, Iskandaneefiya waa inay ahaato mid aan baraf lahayn sababtoo ah Waqooyiga Atlantic hadda, kaas oo biyo diiran u keena xeebaha waqooyi-galbeed ee Yurub. Inkasta oo labada gobol ay ku yaalaan meelo isku mid ah, heerkulka xagaaga ee Scandinavian-ka ayaa si fiican uga sarreeya barafka, halka heerkulka qaybo badan oo ka mid ah Arctic Canadian uu yahay mid ka hooseeya baraf ilaa xagaaga, sida ay sheegeen cilmi-baarayaasha. Kala duwanaanshiyahan awgeed, moodooyinka cimiladu waxay ku dhibtooday inay xisaabiyaan barafka baaxadda leh ee ka soo baxay waqooyiga Yurub oo calaamadeeyay bilawgii da'dii barafka ee u dambeeyay, ayuu yidhi madaxa cilmi-baarista, Marcus Lofverstrom.
"Dhibaatadu waxay tahay ma garanayno halka ay ka yimaadeen xaashiyada barafka (Scandinavianka) iyo waxa sababay inay ku balaadhaan wakhti yar," ayuu yidhi Lofverstrom, oo ah kaaliyaha borofisar cilmiga geosciences iyo madaxa UArizona Earth System Dynamics. Shaybaadhka
Si aad jawaabo u hesho, Lofverstrom waxa uu gacan ka geystay horumarinta qaab aad u adag oo nidaamka Dhulka ah, oo loo yaqaan Qaabka Nidaamka Dhulka Bulshada, kaas oo u oggolaaday kooxdiisa in ay si dhab ah dib u abuuraan xaaladihii jiray bilowgii xilliga glacial ee ugu dambeeyay. Waxaa xusid mudan, inuu balaadhiyey qaabka xaashida barafka ee Grønland si uu u koobo inta badan Hemisphere-ka Woqooyi ee tafatirka sare.
Isticmaalka qaabeynta moodeelkan la cusboonaysiiyay, cilmi-baarayaashu waxay aqoonsadeen marinnada badda ee Jasiiradaha Arctic Archipelago ee Kanada inay yihiin linchpin muhiim ah oo xakameynaya cimilada Waqooyiga Atlaantigga iyo ugu dambeyntii go'aaminta in baraf barafku ay ku koraan Scandinavianka iyo in kale.
Jilidyadu waxay daaha ka qaadeen in ilaa inta albaabbada badda ee Jasiiradaha Arctic ee Kanada ay sii furan yihiin, qaabaynta orbital-ka ee dhulku waxay si ku filan u qaboojisay Hemisphere Waqooyi si ay ugu oggolaato barafyada inay ka dhismaan Waqooyiga Kanada iyo Siberiya, laakiin maaha in Scandinavianka.
Tijaabo labaad, cilmi-baarayaashu waxay ku ekaayeen dhacdo aan hore loo sahamin oo baraf barafku xannibay marin-biyoodka Jasiiradda Arctic ee Kanada. Tijaabadaas, biyaha cusub ee Arctic iyo Waqooyiga Baasifigga - oo sida caadiga ah lagu dhex maro Jasiiradaha Arctic Archipelago ee Kanada - ayaa loo weeciyay bariga Greenland, halkaas oo qulqulka biyaha qoto dheer ay caadi ahaan sameeyaan. Weecintani waxay keentay dib u soo kabasho iyo daciifnimo wareegga qoto dheer ee Waqooyiga Atlaantigga, balaadhinta barafka badda, iyo xaaladaha qaboojinta ee Scandinavia.
"Isticmaalka moodooyinka cimilada iyo falanqaynta qulqulka badda, waxaan muujineynaa in barafka ka sameysma waqooyiga Kanada uu xannibi karo marinnada badda iyo inuu ka leexiyo gaadiidka biyaha ee Arctic ilaa Waqooyiga Atlantic," ayuu yiri Lofverstrom, "taasina waxay keentaa wareegga badda ee daciifka ah. iyo xaaladaha qabow ee ka jira xeebaha Scandinavia, taas oo ku filan in uu bilaabo barafka sii kordhaya ee gobolkaas."
"Natiijooyinkan waxaa taageeraya diiwaannada qulqulka badda ee Waqooyiga Atlantic, kuwaas oo muujinaya caddaynta glaciers ee waqooyiga Kanada dhowr kun oo sano ka hor dhinaca Yurub," ayuu yiri Diane Thompson, kaaliyaha borofisar ee UArizona Department of Geosciences. "Diiwaanada saddaxdu waxay sidoo kale muujinayaan cadaymo soo jiidasho leh oo daciifa wareegga badda ka hor inta aanay glaciers ka samaysan Scandinavia, oo la mid ah natiijooyinkayada qaabaynta."
Si wada jir ah, tijaabooyinku waxay soo jeedinayaan in samaynta barafka badda ee waqooyiga Kanada ay noqon karto horudhac lagama maarmaan u ah glaciation ee Scandinavia, qorayaashu waxay qoraan.
Ku riixida moodooyinka cimilada ee ka baxsan codsigooda dhaqameed ee saadaalinta cimilada mustaqbalka waxay siinaysaa fursad lagu aqoonsado isdhexgalka aan hore loo aqoon ee nidaamka Dhulka, sida isdhexgalka adag iyo mararka qaarkood ka soo horjeeda ee u dhexeeya xaashida barafka iyo cimilada, ayuu yiri Lofverstrom.
"Waxaa suurtagal ah in hababka aan ku aqoonsannay halkan ay khuseeyaan xilli kasta oo glacial ah, ma aha oo kaliya kii ugu dambeeyay," ayuu yidhi. "Waxay xitaa kaa caawin kartaa inaad sharaxdo waqtiyo qabow oo gaagaaban sida da'da yar ee Dryas qabow (12,900 ilaa 11,700 sano ka hor) taas oo calaamadisay kulaylka guud dhamaadka da'da barafka ee ugu dambeysay."
Daraasadda ayaa markii hore lagu daabacay Dabiiciga Dabiiciga. Juun 09, 2022.
