Tsinkaye na Arewacin Atlantic

**Arewacin Atlantic Oscillation** (**NAO**) wani yanayi ne a kan Tekun Atlantika na canji a cikin bambancin Matsin yanayi a matakin teku (SLP)  tsakanin Icelandic Low da Azores High. Ta hanyar sauye-sauye a cikin ƙarfin Icelandic Low da Azores High, yana sarrafa ƙarfin da shugabanci na iskar yamma da kuma wurin waƙoƙin guguwa a fadin Arewacin Atlantic.

An gano NAO ta hanyar karatu da yawa a ƙarshen ƙarni na 19 da farkon ƙarni na 20.  Ba kamar El Niño-Southern Oscillation a cikin Tekun Pacific ba, NAO babban yanayin yanayi ne. Yana daya daga cikin muhimman bayyanar sauyin yanayi a Arewacin Atlantic da yanayin zafi da ke kewaye da shi.

Arewacin Atlantic Oscillation yana da alaƙa da Arctic oscillation (AO) (ko Arewacin Annular Mode (NAM)), amma bai kamata a rikita shi da Atlantic multidecadal oscillation ba (AMO).

## Ma'anar
NAO yana da ma'anoni masu yawa. Abubuwan da suka fi sauƙi a fahimta sune wadanda suka danganci auna bambancin matsin iska tsakanin tashoshin, kamar:

* Lisbon da Stykkishólmur/Reykjavík
* Ponta Delgada, Azores da Stykkishólmur/Reykjavík
* Azores (1865-2002), Gibraltar (1821-2007), da Reykjavík 

Wadannan ma'anoni duk suna da alaƙa da wannan ma'anar arewa (saboda wannan ita ce kawai tashar a yankin tare da dogon rikodin) a Iceland; da kuma wurare daban-daban na kudanci. Dukansu suna ƙoƙari su kama wannan tsari na bambancin, ta hanyar zaɓar tashoshin a cikin "ido" na yankuna biyu masu ɗorewa, Azores High da Icelandic Low (wanda aka nuna a cikin hoto).

Ma'anar da ta fi rikitarwa, kawai zai yiwu tare da cikakkun bayanan zamani da aka samar ta hanyar tsinkaya na yanayi, ya dogara ne akan babban aikin orthogonal (EOF) na matsin lamba. Wannan ma'anar tana da babban matsayi na alaƙa da ma'anar tashar. Wannan yana haifar da muhawara game da ko NAO ya bambanta da AO / NAM, kuma idan ba haka ba, wane daga cikin biyun za a dauke shi mafi yawan bayyanar jiki na tsarin yanayi (kamar yadda ya saba da wanda ya fi fitowa daga bayyanar lissafi).  

## Bayyanawa

Iska ta yamma da ke hurawa a fadin Tekun Atlantika tana kawo iska mai laushi zuwa Turai. A cikin shekarun da yammacin ke da ƙarfi, lokacin rani yana da sanyi, hunturu yana da sauƙi kuma ruwan sama yana da yawa. Idan aka hana yaduwar yamma, zafin jiki ya fi tsananin zafi a lokacin rani da hunturu wanda ke haifar da raƙuman zafi, daskarewa mai zurfi da rage ruwan sama.

Tsarin matsin lamba na dindindin a kan Iceland (Low Icelandic) da kuma tsarin matsin lamba mai tsawo na dindada a kan Azores (Azores High) suna sarrafa shugabanci da ƙarfin iskar yamma zuwa Turai. Ƙarfin dangi da matsayi na waɗannan tsarin sun bambanta daga shekara zuwa shekara kuma wannan bambancin an san shi da NAO. Babban bambanci a cikin matsin lamba a tashoshin biyu (shekara mai girma, wanda ake kira NAO +) yana haifar da karuwar yammaci kuma, saboda haka, lokacin rani mai sanyi da hunturu mai laushi a Tsakiyar Turai da kuma Atlantic. Sabanin haka, idan alamar ta yi ƙasa (NAO-), ana hana yamma, yankunan arewacin Turai suna fama da sanyi mai sanyi kuma guguwa suna tafiya zuwa kudu zuwa Tekun Bahar Rum. Wannan ya kawo karuwar aikin guguwa da ruwan sama zuwa kudancin Turai da Arewacin Afirka.

Musamman a lokacin watanni na Nuwamba zuwa Afrilu, NAO tana da alhakin yawancin bambancin yanayi a yankin Arewacin Atlantic, yana shafar saurin iska da canje-canje na iska, canje-canje a cikin zafin jiki da rarraba danshi da tsananin, yawan da kuma hanyar guguwa. Bincike yanzu ya nuna cewa NAO na iya zama mafi tsinkaye fiye da yadda aka ɗauka a baya kuma ƙwarewar hasashen hunturu na iya yiwuwa ga NAO.

Akwai wasu muhawara game da yadda NAO ke tasiri gajeren lokaci a Arewacin Amurka. Duk da yake mafi yawansu sun yarda cewa tasirin NAO ba shi da yawa a kan Amurka fiye da na Yammacin Turai,  An kuma yi imanin NAO yana shafar yanayi a yawancin yankunan tsakiya da gabashin Arewacin Amurka. A lokacin hunturu, lokacin da alamar ta yi girma (NAO +), Azores High yana jawo karfi kudu maso yamma a kan rabin gabashin nahiyar Arewacin Amurka wanda ke hana iska ta Arctic daga nutsewa kudu (a cikin Amurka kudu na latitude 40). Tare da haɗuwa da El Niño, wannan tasirin na iya haifar da hunturu mai zafi sosai a saman Midwest da New England, amma tasirin da ke kudu da waɗannan yankuna yana da muhawara. Sabanin haka, lokacin da alamar NAO ta yi ƙasa (NAO-), sassan tsakiya da arewa maso gabashin Amurka na iya haifar da barkewar sanyi na hunturu fiye da yadda aka saba da hadari mai nauyi. A lokacin rani, ana tunanin NAO- mai ƙarfi don ba da gudummawa ga raunin jet wanda ke janye tsarin yanki zuwa cikin Atlantic Basin yana ba da guddina sosai ga raƙuman zafi masu tsawo a Turai, duk da haka, binciken da aka yi kwanan nan ba ya nuna shaidar waɗannan ƙungiyoyi.

## Manazarta