Kusan sauye-sauye na shekara-shekara

Tsakanin oscillation na kusan shekaru biyu (QBO) wani oscillation ne na kusan lokaci-lokaci na iska ta equatorial tsakanin gabas da yamma a cikin stratosphere na wurare masu zafi tare da matsakaicin lokacin watanni 28 zuwa 29. Tsarin iska mai sauyawa yana tasowa a saman ƙananan stratosphere kuma yana yaduwa ƙasa a kusan    a kowane wata har sai sun ɓace a tropopause. Motsi zuwa ƙasa na gabas yawanci ba dai-dai ba ne fiye da na gabas. Girman matakin gabas yana da kusan sau biyu fiye da na matakin yamma. A saman yanki QBO na tsaye, easterlies sun mamaye, yayin da a kasa, ana iya samun westerlies. A matakin , dangane da iskar zonal ta kowane wata, mafi karfi da aka rubuta a gabas ya kasance 29.55 m / s a watan Nuwamba na shekara ta 2005, yayin da mafi karfi da ya rubuta a yamma ya kasance 15.62 m / s kawai a watan Yunin shekara ta 1995.  

 Ƙa'idar 
A cikin shekarar 1883, fashewar Krakatoa ya haifar da bin diddigin gani na toka na dutsen wuta a cikin stratosphere. Wannan bin diddigin gani ya haifar da gano iskar gabas tsakanin kilomita 25 zuwa 30 sama da farfajiya. An kira iskar da Krakatau easterlies. A cikin 1908, balloons na bayanai da aka kaddamar sama da Tafkin Victoria a Afirka sun rubuta iskõki na yamma a cikin matakan stratospheric na yanayi. Wadannan binciken, a lokacin, an yi tunanin sun saba wa binciken 1883.  Koyaya, iskõkin da za su zama sanannun QBO an gano su da ke motsawa tsakanin yamma da gabas a cikin shekarun 1950 ta hanyar masu bincike a Ofishin Meteorological na Burtaniya. Dalilin waɗannan iskõkin QBO ya kasance ba a bayyane ba na ɗan lokaci. Binciken rediyo ya nuna cewa lokacinsa ba shi da alaƙa da sake zagayowar shekara-shekara, kamar yadda yake ga sauran alamu da yawa na yaduwar stratospheric. A cikin shekarun 1970s Richard Lindzen da James Holton sun gane cewa sauye-sauyen iska na lokaci-lokaci ya haifar da raƙuman yanayi da ke fitowa daga yanayin zafi wanda ke tafiya sama kuma yana ɓacewa a cikin stratosphere ta hanyar sanyaya radiative. An yi muhawara sosai game da ainihin yanayin raƙuman ruwa da ke da alhakin wannan sakamako; a cikin 'yan shekarun nan, duk da haka, ana ganin raƙuman nauyi a matsayin babban mai ba da gudummawa kuma yanzu ana kwaikwayon QBO a cikin ƙaruwar samfuran yanayi. 

 Tasirin 
Tasirin QBO sun haɗa da haɗuwa da ozone na stratospheric ta hanyar zagayawar sakandare da QBO ya haifar, gyare-gyaren ruwan sama, da kuma tasiri a kan zagayawar stratospherical a cikin hunturu na arewacin arewa (wanda aka shiga cikin wani ɓangare ta hanyar canji a cikin mitar dumi na kwatsam). Matakan Easter na QBO sau da yawa suna haɗuwa da karin dumi na kwatsam, rafin jet na Atlantic, da hunturu mai sanyi a Arewacin Turai da Gabashin Amurka. Sabanin haka, matakai na yammacin QBO sauƙin sau da yawa yana haɗuwa da hunturu masu sauƙi a Gabashin Amurka da kuma jet jet na Atlantic mai ƙarfi tare da sanyi, hunturu mai laushi a Arewacin Yuropa. Bugu da kari, an nuna QBO yana shafar yawan guguwa a lokacin guguwa da aka yi a cikin Atlantic. An kuma gudanar da bincike don bincika yiwuwar dangantaka tsakanin ENSO (El Niño-Southern Oscillation) da QBO.

 Manazarta