Ithonya Lezigaba Zenyanga Esimweni Sezulu Nasesimweni Sezulu
Inyanga ibilokhu iyindaba ethandwayo kubantu isikhathi eside, hhayi nje ngenxa yobuhle bayo esibhakabhakeni sasebusuku, kodwa futhi nangethonya layo ezimweni ezahlukene eMhlabeni. Amasiko amaningi ahlobanisa izigaba zenyanga nokuziphatha kwezilwane, ukukhula kwezitshalo, amaza olwandle, ngisho nokushintsha kwesimo sezulu. Umbuzo ovame ukubuzwa uwukuthi: ingabe izigaba zenyanga zingasithonya ngempela isimo sezulu nesimo sezulu? Ukuze siphendule lokhu, sidinga ukuhlukanisa phakathi kwamaqiniso esayensi asunguliwe—njengethonya lenyanga kumaza—kanye nezimangalo ezibuthakathaka noma ezingavumelani—njengendima yenyanga “njengomlawuli” wemvula yansuku zonke.
Ukuqonda izigaba zenyanga nokuthi yini eshintshayo ngempela
Izigaba zenyanga zenzeka ngenxa yokushintsha kwezikhundla zeNyanga, uMhlaba, neLanga. Uma iNyanga iphakathi koMhlaba neLanga, sibona iNyanga Entsha. Uma iNyanga ibhekene neLanga (uMhlaba phakathi), sibona iNyanga Egcwele. Phakathi kwalezi zikhundla ezimbili, sibona izigaba zeKota Yokuqala neKota Yesithathu, kanye nezigaba zenyanga kanye ne-gibbous. Okuwukuphela kwento eshintshayo yingxenye yobuso beNyanga ekhanyiswa yiLanga futhi ebonakala eMhlabeni—hhayi iNyanga ekhipha noma yikuphi ukukhanya kwayo.
Ngokwemvelo, izindlela ezimbili eziyinhloko iNyanga engathonya ngazo uMhlaba ngamandla ayo adonsela phansi kanye—ngezinga elincane kakhulu—ukushintshashintsha kokukhanya kwasebusuku (ukukhanya kwenyanga). Amandla adonsela phansi eNyanga angashukumisa amanzi futhi athinte ngisho nomkhathi kancane. Okwamanje, izinguquko ekukhanyeni kwasebusuku zingathonya ukuziphatha kwezinto eziphilayo, kodwa umthelela wazo esimweni sezulu ngokuvamile awuqondile.
Ithonya elisobala kakhulu: amagagasi
Ubudlelwano phakathi kweNyanga namaza olwandle buyisibonelo esisobala nesilinganiswayo saleli thonya. Ngesikhathi seNyanga Entsha kanye neNyanga Egcwele, iLanga, uMhlaba, kanye neNyanga cishe zihambisana. Ngaphansi kwalezi zimo, amandla adonsela phansi eNyanga neLanga ayaqinisana, akhiqize amanzi aphezulu, abizwa ngokuthi amanzi asentwasahlobo. Ngokuphambene nalokho, ngesikhathi sesigaba seKota Yokuqala kanye nesigaba seKota Yesithathu, amandla adonsela phansi eNyanga neLanga "ayalingana", okuholela ekujuleni kolwandle okuncane, okubizwa ngokuthi amanzi asemanzini.
Amagagasi awagcini nje ngokuthinta izindawo ezisogwini. Kwezinye izindawo, angathonya ukuguquguquka kwamanje, ukuxubana kwamanzi olwandle, kanye namazinga okushisa olwandle endawo. Lezi zici, nazo, zingasebenzisana nesimo sezulu sasogwini—isibonelo, ukwakheka kwenkungu, umoya ovunguzayo osuka ezweni uya olwandle, noma induduzo yokushisa. Kodwa-ke, la mathonya asendaweni futhi ngokuvamile awanamandla kakhulu kunezishoshovu ezinkulu zesimo sezulu njengemvula, umehluko wokucindezela komoya, kanye nezinhlelo zesiphepho.
Ingabe isigaba senyanga sithinta umkhathi nemvula?
Ngokwenkolelo-mbono, uma iNyanga ingakwazi "ukudonsa" amanzi olwandle, ingadonsa nomoya. Ngempela, kukhona amagagasi omoya, okuyi-escillations evamile yokucindezela komoya ngenxa yethonya lamandla adonsela phansi kanye nokushisa yiLanga. Kodwa-ke, amandla adonsela phansi eNyanga mancane kakhulu kunokushintshashintsha kwansuku zonke okubangelwa ukushisa kwelanga. Lokhu kusho ukuthi isignali yeNyanga emkhathini ikhona, kodwa ubukhulu bayo buncane.
Izifundo eziningana ziye zazama ukuhlola ukuthi imvula, ukuduma kwezulu, noma ukwakheka kwamafu kungenzeka yini phakathi nezigaba ezithile, njengokuzungeza iNyanga Egcwele noma iNyanga Entsha. Imiphumela ixubile: ezinye izifundo zithole ubudlelwano obubuthakathaka ezindaweni ezithile nasezinkathini ezithile, kodwa eziningi azitholanga ubudlelwano obuqhubekayo. Enye yezinselele ezinkulu ukuthi isimo sezulu siyinkimbinkimbi kakhulu futhi sithonywa yizici eziningi ezivelele: izinga lokushisa lolwandle, umswakama, ukuhlangana komoya, ukuma komhlaba, amagagasi omoya, ngisho nezenzakalo ezinkulu ezifana ne-El Niño–La Niña. Njengoba kunomsindo omkhulu kangaka, kunzima ukuhlukanisa isignali encane ezigabeni zenyanga—uma ikhona—ekushintsheni kwemvelo.
Ngaphezu kwalokho, ukuhlobana akusho njalo ukuthi kubangelwa yini. Isibonelo, uma isikhathi sonyaka wemvula esifundeni sihambisana nesigaba esithile senyanga onyakeni othile, lokhu kungase kubonakale "kukholisa," kodwa kungabi nendlela eqinile yomzimba noma kungami lapho kuhlaziywa isikhathi eside.
Inyanga neziphepho ezinkulu: inganekwane noma isisekelo?
Kuvame ukukholelwa ukuthi inyanga egcwele ibangela iziphepho, imimoya enamandla, noma ukuzamazama komhlaba. Uma kunesimo sezulu esibi kakhulu, ubufakazi obuqinile besayensi bulinganiselwe. Iziphepho zasezindaweni ezishisayo, isibonelo, zinqunywa kakhulu amazinga okushisa afudumele olwandle, ukuqedwa komoya ophansi, umswakama owanele, kanye nokuphazamiseka kokuqala emkhathini. Umjikelezo wokuphila kwesiphepho uhlala izinsuku eziningana kuya emavikini, ngakho-ke noma yiliphi ithonya lesigaba senyanga kuzodingeka libe namandla ngokwanele ukushintsha lezi zimo ezibalulekile—into engakaze iboniswe njalo.
Kodwa-ke, kunesici esisodwa esivame ukwenza "isigaba senyanga sibonakale sithonya" umthelela wesiphepho: izinga lolwandle. Uma isiphepho noma amagagasi aphezulu ehlangana namagagasi entwasahlobo (ezungeze inyanga entsha noma egcwele), ingozi yezikhukhula kanye nokugeleza kwamagagasi inganda. Ngakho-ke, akukhona ukuthi inyanga "idala iziphepho," kodwa kunalokho ukuthi isigaba senyanga singabhebhethekisa imiphumela yasogwini lapho kuvela isimo sezulu esibi.
Umthelela esimweni sezulu: omncane kakhulu futhi ongaqondile
Isimo sezulu yizibalo zesikhathi eside zesimo sezulu—izilinganiso, ukuguquguquka, kanye nezitayela eminyakeni emashumi noma ngaphezulu. Ithonya leNyanga esimweni sezulu soMhlaba ngokuvamile libhekwa njengelincane kakhulu uma liqhathaniswa nezici ezifana nemisebe yelanga, ukwakheka komkhathi (amagesi okushisa), ukujikeleza kolwandle, ukuqhuma kwezintaba-mlilo, kanye nezinguquko zokusetshenziswa komhlaba.
Kodwa-ke, kunengxoxo yesayensi mayelana nokwehluka kwesikhathi eside ohlelweni loMhlaba okuhlobene nemingcele ye-lunar orbital, njengomjikelezo we-nodal weminyaka engaba ngu-18,6 othonya amaphethini athile okuhamba kwamanzi. Lo mjikelezo ungaguqula ngobuqili izinga lokuxubana kwamanzi olwandle noma izinga lolwandle lesifunda, okungase kuhlangane nokwehluka kwesimo sezulu. Kodwa-ke, le miphumela ivame ukuba mincane, futhi ivame ukubonakala njengengxenye eyodwa encane ngaphakathi kohlelo olukhulu.
Kubalulekile ukugcizelela ukuthi izinguquko zesimo sezulu zanamuhla ezibonwayo—ngokwesibonelo, izitayela zokufudumala komhlaba—azinakuchazwa ngezigaba zenyanga. Ubukhulu kanye nesiqondiso salezi zinguquko kuhambisana kakhulu nokwanda kwamagesi okushisa abangelwa imisebenzi yabantu.
Kungani izinkolelo mayelana nenyanga nesimo sezulu zihlala ziqinile?
Kunezizathu eziningana ezenza ukuthi ukuxhumana phakathi kwenyanga nesimo sezulu kuzwakale "kungokoqobo" kangaka kubantu abaningi. Okokuqala, izigaba zenyanga zibonakala kalula futhi zinikeza uphawu lwesikhathi olucacile. Lapho kwenzeka isenzakalo sezulu eduze kweNyanga Egcwele, ubuchopho bethu buvame ukusikhumbula kakhulu kunalapho senzeka ngobusuku obujwayelekile. Okwesibili, isimo sezulu siyashintsha ngokwemvelo, ngakho-ke kuhlala kunezibonelo ezingahlanganiswa "nesigaba esithile senyanga. Okwesithathu, amasiko asendulo ezolimo kanye nokudoba ayethembele kakhulu emjikelezweni wenyanga ukuze azulazule futhi ahambisane namagagasi, ngakho-ke kungokwemvelo ukuthi ithonya lawo lingafinyelela ekuchazeni okujwayelekile kwesimo sezulu.
Isiphetho
Izigaba zenyanga zinethonya langempela nelilinganiswayo eMhlabeni, ikakhulukazi ngamagagasi. Le miphumela ingadlulela endaweni yakini ezimweni zasogwini futhi yandise ingozi yezikhukhula zamagagasi uma ihlanganiswa nesimo sezulu esibi. Kodwa-ke, ngezenzakalo zesimo sezulu zansuku zonke—njengemvula, ukuduma kwezulu, noma umoya—ithonya lezigaba zenyanga, uma likhona, ngokuvamile libuthakathaka futhi alihambisani uma liqhathaniswa nezishayeli zomkhathi ezibusa kakhulu. Ezikalini zesimo sezulu zesikhathi eside, umnikelo wezigaba zenyanga nawo mncane kakhulu futhi awukwazi ukuchaza ushintsho lwesimo sezulu lwanamuhla.
Ngakho-ke, isigaba senyanga siqondwa kangcono njengesici sesibili: esibalulekile kumagagasi kanye nemithelela yasogwini, kodwa hhayi "umlawuli" oyinhloko wesimo sezulu soMhlaba kanye nesimo sezulu. Ngokubikezela isimo sezulu, amamodeli e-meteorological, idatha yesathelayithi, kanye nokuqonda ukuguquguquka komkhathi kuhlala kuyithuluzi elithembekile kakhulu, kuyilapho isigaba senyanga singacatshangelwa ikakhulukazi lapho kuhlolwa izingozi ezihlobene namagagasi kanye nezimo zasogwini.
