Isimo sezulu

Isimo sezulu sibhekisela esimweni somoya womhlaba endaweni ethile nesikhathi esithile, ngokuvamile esichazwa ngezinga lokushisa, umswakama, ukuminyana kwamafu, nokuzinza komoya. Emhlabeni, iningi lezenzakalo zesimo sezulu zenzeka engxenyeni  ephansi yomkhathi womhlaba obizwa ngokuthi, I-troposphere,   engaphansi nje kwe-I-stratosphere. Isimo sezulu sibhekisela emazingeni okushisa asukwini, imvula, nezinye izimo zomoya, kuyilapho isimo sezulu siyisilinganiso sezimo zomoya ngezikhathi ezinde. Uma isetshenziswa ngaphandle kokufaneleka, "isimo sezulu" ngokuvamile siqondwa sisho isimo sezulu somhlaba.

Isimo sezulu siqhutshwa umehluko wengcindezi  yomoya,, Izinga lokushisa, kanye nomswakama phakathi kwendawo eyodwa nenye. Lomehluko  ungavela ngenxa ye- ngela yelanga edaweni ethile, eguquka ngokuya ngobubanzi bendawo -(latitude). Umehluko omkhulu wezinga lokushisa eli phakathi komoya wasezindaweni ezibandayo(emapholeni) nowase zindaweni ezishisayo (tropiki) udala ukujikeleza komoya  okukhulu kakhulu: i-Hadley cell, I-ferrel cell, i'I-polar cell, kanye ne-jet stream. Izinhlelo zesimo sezulu ezisezindaweni e-latitudes ephakathi nendawo, njengeziphepho ze-extratropical, zidalwa ukungazinzi kokugeleza kwe-jet streamflow. Ngenxa yokuthi i-axis yomhlaba itshekile maqondana nendiza yayo yokuzungeza ilanga (ebizwa ngokuthi I-ecliptic), Ukukhanya kwelanga kwenzeka ema-engela ahlukene ngezikhathi ezahlukene zonyaka. Emhlabeni, izinga lokushisa livame ukufinyelela ku-±40 °C (-40 °F kuya ku-104 °F) minyaka yonke. Eminyakeni eyizinkulungwane, izinguquko emzileni womhlaba zingathinta inani nokusabalala kwAmandla elanga atholakala eMhlabeni, ngaleyo ndlela zithonye isimo sezulu sesikhathi eside Ukushintsha kwesimo sezulu somhlaba wonke.   

Emhlabeni, Isimo sezulu sivame ukuhlanganisa umoya, ifu, imvula, iqhwa, inkungu Iziphepho zothuli. kanyi ezinye izenzakalo ezivame kakhulu zihlanganisa Izinhlekelele ezingokwemvelo njengeziphepho, iziphepho, isiphepho Iziphepho zeqhwa. Cishe zonke izimo zezulu ezijwayelekile zenzeka kuyi-troposphere (ingxenye engaphansi yomoya osemkhathini). Isimo sezulu senzeka kuyi-stratosphere futhi singathinta isimo sezulu esiphansi kuyi-troposphere, kodwa izindlela eziqondile aziqondwa kahle.

Isimo sezulu senzeka ngokuyinhloko ngenxa yobukhulu bomoya, ilanga lokushisa kanye nokwehluka kwomswakama kusuka kwenye indawo kuya kwenye. Lokhu kwehluka kungahle kwenzeke ngenxa ye-engela yelanga kunoma iyiphi indawo ethile, ehlukahluka nge-latitude ezindaweni ezishisayo ngolunye ulimi, lapho umuntu ehlala kude kakhulu nezindawo ezishisayo, yilapho i-engela yelanga iphansi, okudala ukuthi lezo zindawo zigcina ziphola kakhulu ngenxa yokusakazeka Ukukhanya kwelanga endaweni enkulu. Umehluko onamandla wokushisa phakathi komoya wasezindaweni ezishisayo nowasendaweni eshisayo ubangela amangqamuzana amakhulu okujikeleza komkhathi kanye nomfudlana we-jet. izimiso zesimo sezulu ezindaweni eziphakathi nendawo, njengazo nje iziphepho ze-extratropical, zibangelwa ukungazinzi kokugeleza kwe-jet stream (bheka i-baroclinity). Izimiso zesimo sezulu ezindaweni ezishisayo, njengezimvula ezinkulu noma izimiso ezihleliwe Ukuduma, zibangelwa izinqubo ezahlukahlukene.