Tsarin yaduwa na gaba ɗaya

Misali na yaduwa (**GCM**) wani nau'in Tsarin yanayi ne. Yana amfani da samfurin lissafi na yaduwar sararin samaniya ko teku. Yana amfani da ma'aunin Navier-Stokes a kan wani yanki mai juyawa tare da kalmomin thermodynamic don tushen makamashi daban-daban (radiation, latent zafi). Wadannan daidaitattun sune tushen shirye-shiryen kwamfuta da aka yi amfani da su don kwaikwayon yanayin duniya ko tekuna. GCMs na yanayi da na teku (AGCM da OGCM) sune mahimman abubuwan da ke tattare da kankara ta teku da abubuwan da ke ƙasa.

Ana amfani da GCMs da samfuran yanayi na duniya don Hasashen yanayi, fahimtar yanayi, da hasashen Canjin yanayi.

GCMs na yanayi (AGCMs) suna tsara yanayin yanayi kuma suna sanya Yanayin zafi na teku a matsayin yanayin iyaka. Haɗin yanayi-teku GCMs (AOGCMs, misali HadCM3, EdGCM, GFDL CM2.X, ARPEGE-Climat)  sun haɗu da samfuran biyu. Tsarin yanayi na farko na yaduwar da ya haɗu da tsarin teku da na yanayi an haɓaka shi a ƙarshen shekarun 1960 a NOAA Geophysical Fluid Dynamics Laboratory  AOGCMs suna wakiltar ƙwarewar rikitarwa a cikin samfuran yanayi kuma suna da matakai da yawa kamar yadda zai yiwu. Koyaya, har yanzu suna cikin ci gaba kuma rashin tabbas ya kasance. Ana iya haɗa su da samfuran wasu matakai, kamar sake zagayowar carbon, don inganta tasirin sakamako. Irin waɗannan samfuran tsarin da aka haɗa a wasu lokuta ana kiransu ko dai "model na tsarin ƙasa" ko "model na yanayi na duniya".

Syukuro Manabe da Kirk Bryan ne suka kirkiro sassan da aka tsara don shekaru goma zuwa ƙarni a dakin gwaje-gwaje na Geophysical Fluid Dynamics (GFDL) a Princeton, New Jersey. Wadannan samfurori sun dogara ne akan hadewar nau'ikan ruwa masu yawa, sunadarai da kuma wani lokacin lissafin halittu.

## Kalmomin
Sunan *GCM* da farko ya tsaya don General Circulation Model. Kwanan nan, ma'anar ta biyu ta fara amfani da ita, wato *Tsarin Yanayi na Duniya*. Duk da yake waɗannan ba sa nufin abu ɗaya, General Circulation Models yawanci kayan aikin da ake amfani da su don ƙirar yanayi, sabili da haka ana amfani da kalmomin biyu a wasu lokuta. Koyaya, kalmar "model na yanayi na duniya" ba ta da tabbas kuma tana iya nufin tsarin hadin gwiwa wanda ya haɗa da abubuwa da yawa ciki har da tsarin yaduwar gaba ɗaya, ko kuma yana iya nufin babban aji na samfuran yanayi waɗanda ke amfani da hanyoyi daban-daban don wakiltar yanayi ta hanyar lissafi.

## Tsarin yanayi da na teku
Za'a iya haɗa yanayin yanayi (AGCMs) da GCMs na teku (OGCMs) don samar da tsarin yaduwar yanayi-teku (CGCM ko AOGCM). Tare da ƙarin submodels kamar samfurin kankara na teku ko samfurin don evapotranspiration a kan ƙasa, AOGCMs sun zama tushen cikakken tsarin yanayi.

## Tsarinsa
General Circulation Models (GCMs) suna rarraba daidaitattun don motsi na ruwa da canja wurin makamashi kuma suna haɗa waɗannan a tsawon lokaci. Ba kamar samfuran da suka fi sauƙi ba, GCMs sun raba yanayi da / ko teku zuwa grid na "kwayoyin" daban-daban, waɗanda ke wakiltar raka'a na lissafi. Ba kamar samfuran da suka fi sauƙi ba waɗanda ke yin haɗuwa, matakai na ciki zuwa tantanin halitta - kamar convection - waɗanda ke faruwa a kan ma'auni da yawa don a warware su kai tsaye ana daidaita su a matakin tantanin halitta, yayin da wasu ayyuka ke sarrafa dubawa tsakanin sel.

### Gidan yanar gizo
Ana yin ma'aunin ruwa don AGCMs ''Q''" rel="mw:WikiLink" title="Temperature">*T* hanyar amfani da ko dai hanyar bambancin ƙayyadadden ko Hanyar bakan gizo. Don bambance-bambance masu iyaka, ana sanya grid a kan yanayi. Matsayi mafi sauki yana amfani da madaidaiciyar tsinkaye na kusurwa (watau, latitude / longitude grid). Koyaya, ana amfani da grid ɗin da ba na rectangular ba (misali, icosahedral) da grid ɗin ƙuduri mai canji  sau da yawa. Ana iya shirya samfurin LMDz don ba da babban ƙuduri a kan kowane ɓangaren da aka ba da na duniya. HadGEM1 (da sauran samfuran teku) suna amfani da grid na teku tare da ƙuduri mafi girma a cikin wurare masu zafi don taimakawa warware hanyoyin da aka yi imanin suna da mahimmanci ga El Niño Southern Oscillation (ENSO). Misalai na bakan gizo galibi suna amfani da grid na Gaussian, saboda lissafin canji tsakanin bakan gizo da sararin samaniya. Shawarwarin AGCM na yau da kullun suna tsakanin digiri 1 zuwa 5 a latitude ko longitude: HadCM3, alal misali, yana amfani da 3.75 a longitude da digiri 2.5 a latitude, yana ba da grid na maki 96 da 73 (96 x 72 ga wasu masu canji); kuma yana da matakan tsaye 19. Wannan yana haifar da kusan 500,000 "masu mahimmanci", tunda kowane grid point yana da masu canji huɗu (T, Q), kodayake cikakken ƙidaya zai ba da ƙarin (kurmi; matakan ƙasa). HadGEM1 yana amfani da grid na digiri 1.875 a cikin longitude da 1.25 a cikin latitude a cikin yanayi; HiGEM, bambancin babban ƙuduri, yana amfani da digiri 1.25 x 0.83 bi da bi. Wadannan ƙuduri sun fi ƙasa da yadda ake amfani da su don hasashen yanayi. Shawarwarin teku suna da girma, alal misali, HadCM3 yana da maki 6 na grid na teku a kowane matsayi na grid a kwance.

## Manazarta