I-Los Milankovitch imijikelezo kusekelwe eqinisweni lokuthi izinguquko ze-orbital zinesibopho senkathi yeqhwa kanye ne-interglacial. Isimo sezulu siyahlukahluka ngokuya ngemingcele emithathu eyisisekelo eshintsha ukunyakaza koMhlaba. Abantu abaningi bathi ukuguquguquka kwesimo sezulu kubangelwa imijikelezo yaseMilankovitch, kodwa akunjalo.
Ngenxa yalesi sizathu, sizonikezela lesi sihloko ukuze sikutshele ukuthi imijikelezo yaseMilankovitch isebenza kanjani nokuthi ibaluleke kangakanani i-climate pair emhlabeni wethu.
Iyini imijikelezo yaseMilankovitch?
Sibhekene nenye yamamodeli esayensi abaluleke kakhulu. Ngaphambi kokufika komjikelezo weMilankovitch ngekhulu lama-XNUMX, izici ezaphazamisa ukuguquka kwesimo sezulu eMhlabeni zazingaziwa kakhulu emphakathini wesayensi. Abacwaningi abafana noJoseph Adhémar noma uJames Croll bafuna izimpendulo kusukela ekuqhwakeleni kweqhwa phakathi nekhulu leshumi nesishiyagalolunye kuya ezikhathini zokuguquka kwesimo sezulu okunamandla. Izincwadi nokucwaninga kwakhe kwakunganakwa kwaze kwaba yilapho isazi sezibalo saseSerbia uMilankovic ezilanda futhi waqala ukusebenzela inkolelo-mbono eyashintsha yonke into.
Manje sesiyazi ukuthi abantu bakuthonya kanjani ukuguquguquka kwesimo sezulu, kodwa kubalulekile futhi ukuqaphela ukuthi akuyona into kuphela. Ukushintsha kwesimo sezulu eMhlabeni nakho kungachazwa ngethonya lezici ezingaphandle kweplanethi. Imijikelezo yaseMilankovitch ichaza ukuthi izinguquko ze-orbital zinomthelela kanjani ekushintsheni kwesimo sezulu eMhlabeni.
Milankovitch umjikelezo nemingcele
Isimo sezulu sihlotshaniswa nezinguquko ze-orbital. UMilankovitch ukholelwa ukuthi imisebe yelanga ayanele ukushintsha ngokuphelele isimo sezulu soMhlaba. Nokho, izinguquko emzileni woMhlaba zingenzeka. Zichazwa kanje:
- Iqhwa: ukucaca okuphezulu, ukutsheka okuphansi, kanye namabanga amakhulu phakathi koMhlaba neLanga kubangela umehluko omncane phakathi kwezinkathi zonyaka.
- I-Interglacials: Ukucaca okuphansi, ukutsheka okuphezulu, kanye namabanga amafushane phakathi koMhlaba neLanga, okuholela ezinkathini zonyaka ezahlukene.
Ngokusho kwe-Milankovitch theory, iguqula ukunyakaza kokuhumusha nokujikeleza kweplanethi ngokusekelwe kumingcele emithathu eyisisekelo:
- I-eccentricity ye-orbit. Kusekelwe ekutheni i-ellipse inwebe kangakanani. Uma i-orbit yomhlaba i-elliptical ngaphezulu, i-eccentricity inkulu, futhi ngokuphambene nalokho uma iyindilinga kakhulu. Lokhu kuhlukahluka kungenza umehluko we-1% kuya ku-11% enanini lemisebe yelanga etholwa nguMhlaba.
- Ukuthambekela. Lezi izinguquko ku-engeli ye-eksisi Yomhlaba yokuzungezisa. Idiphu ishintshashintsha phakathi kuka-21,6º kanye no-24,5º njalo eminyakeni engu-40.000.
- Ukulungiselela Sikhuluma ngokwenza i-eksisi yokuzungezisa ibhekane nendawo yokuzungezisa. Umthelela wayo esimweni sezulu uwumphumela wokushintsha ukuma okuhlobene kwe-solstices nama-equinoxes.
Isazi sezibalo saseSerbia sinethemba lokubonisa ekuqaleni kwekhulu lama-XNUMX ukuthi, ngaphezu kwethonya lomuntu, kudingeka siqonde indlela iplanethi yethu eziphatha ngayo nokuthi izinguquko ezijikelezayo zingasishintsha kanjani isimo sezulu.
Nokho, indima yethu ekuguquguqukeni kwesimo sezulu ayinakuphikiswa. Umuntu ushintsha ukuziphatha kwemijikelezo evamile yoMhlaba kanye nesimo sezulu, ngakho-ke kufanele siqale ukuba nokuziphatha okusimeme okuvikela imvelo.
imiphumela yesimo sezulu
Okwamanje, ngenxa yokuthi uMhlaba uhamba phakathi kwe-perihelion phakathi nobusika obusenyakatho nenkabazwe (ngoJanuwari), ibanga elifushane ukusuka elangeni livimbela kancane ukubanda kwasebusika kuleyo ndawo. Ngokufanayo, njengoba uMhlaba use-aphelion ngesikhathi sasehlobo esisenyakatho nenkabazwe (July), ebangeni elikhudlwana ukusuka elangeni ivimbela ukushisa kwasehlobo. Ngamanye amazwi, ukwakheka kwamanje kokuzungeza komhlaba ilanga kusiza ekunciphiseni ukuhluka kwezinga lokushisa kwesizini endaweni esenyakatho nenkabazwe.
Ngokuphambene nalokho, umehluko wezinkathi zonyaka eningizimu nenkabazwe uye wagcizelelwa. Nokho, njengoba ihlobo lide enyakatho nobusika bufushane lapho ilanga likude noMhlaba, umehluko echibini lamandla lesizini elitholiwe awumkhulu kangako.
Imibono
Imibono yendabuko ye-paleoclimate iphakamisa ukuthi i-glacialization ne-deglazing yaqala ezindaweni eziphakeme enyakatho nenkabazwe futhi yasakazekela kuyo yonke iplanethi. NgokukaMilankovitch, ihlobo elipholile liyadingeka ezindaweni eziphakeme ezisenyakatho nenkabazwe ukuze kuncishiswe ukuncibilika kwehlobo nokuvumela elinye iqhwa. Ikwindla iza ebusika ngaphambili.
Ukuze lokhu kunqwabelana kweqhwa neqhwa kwenzeke, ukungezwani komzimba ehlobo kufanele kube phansi, okwenzeka lapho ihlobo elisenyakatho liqondana ne-aphelion. Lokhu kwenzeka eminyakeni engaba ngu-22.000 edlule, lapho kwenzeka khona ukuthuthuka kweqhwa okukhulu kakhulu (namanje kuyenzeka, kodwa kube nomthelela omkhulu kunanamuhla ngenxa ye-eccentricity enkulu ye-orbit). Ngokuphambene, ukulahlekelwa yiqhwa ezwekazini kuyathandeka uma i-latitudes ephezulu ine-insolation ephezulu ehlobo kanye nokungazwakali kahle kwasebusika, okuholela ehlobo elifudumele (ukuncibilika okwengeziwe) nobusika obubandayo (iqhwa elincane).
Lesi simo safinyelela umkhawulo eminyakeni engaba ngu-11.000 XNUMX edlule.. Izikhundla ze-perihelion kanye ne-aphelion zishintsha ukusatshalaliswa kwesizini kwamandla elanga futhi kungenzeka kube nomthelela omkhulu enqubweni yokugcina yokuwohloka kweqhwa.
Kodwa-ke, kufanele kucatshangelwe ukuthi ukushuba kwemisebe ehlobo kuhambisana ngokuphambene nesikhathi sasehlobo. Lokhu kungenxa yomthetho wesibili kaKepler, othi ukunyakaza koMhlaba kuyashesha njengoba udlula ku-perihelion. Lesi isithende sika-Achilles sethiyori yokuthi i-precession yayibusa i-Ice Age. Idiphu ibaluleke kakhulu kunokwendulela kanye nezici ze-precession lapho kucatshangelwa ukujula kwelanga ngesikhathi sasehlobo (noma okungcono kakhulu, phakathi nezinsuku lapho ingubo yasenyakatho incibilika). Umjikelezo we-equinox precession ungase unqume kakhulu esimweni sezulu esishisayo kunasezifundeni ezipholile, lapho i-axial tilt ibonakala idlala indima enkulu.
Ngithemba ukuthi ngalolu lwazi ungafunda kabanzi mayelana nemijikelezo yaseMilankovich nokuthi ithinta kanjani isimo sezulu.