Tsuntsaye na yanayin zafi na teku

Tekun zafi mai ƙarfi shine tsarin jiki wanda canje-canje a cikin matsakaicin tilasta radiative ke tasiri ga gradients na Yanayin zafi na teku a cikin Tekun Pacific da ƙarfin yaduwar Walker. Ƙarin tilasta radiative (warming) ya fi tasiri a yammacin Pacific fiye da gabas inda hauhawar ruwan sanyi ke rage canjin zafin jiki. Wannan yana ƙara yanayin zafin jiki na gabas da yamma kuma yana ƙarfafa yaduwar Walker. Rage radiative tilasta (kayan sanyi) yana da akasin haka.

An kira wannan tsari don bayyana bambance-bambance a cikin yanayin zafin jiki na Tekun Pacific wanda ke da alaƙa da insolation da bambancin yanayi. Hakanan yana iya zama alhakin alaƙar da aka yi la'akari da ita tsakanin abubuwan da suka faru na El Niño da fashewar dutsen wuta, da kuma canje-canje a cikin yanayin zafin jiki wanda ya faru a cikin karni na 20. Ko yanayin zafi na teku yana sarrafa martani na Tekun Pacific ga dumamar duniya ba a bayyane yake ba, saboda akwai matakai masu gasa a wasa; mai yiwuwa, zai iya fitar da yanayin yanayi na La Niña a lokacin dumamar farko kafin wasu matakai su mamaye shi.

## Tarihi
Yankin Equatorial Pacific babban yanki ne na Duniya dangane da tasirin dangi a kan yaduwar yanayi na duniya. Halin yanayin zafin jiki na gabas da sama an haɗa shi da yaduwar yanayi, yaduwar Walker,  kuma ana ci gaba da sarrafa shi ta hanyar yanayi da yanayin teku.  Yammacin Pacific yana da abin da ake kira "wurin zafi", inda ake samun Yanayin zafi na teku (SSTs) na Duniya. A gabashin Pacific kuma wani yanki da ake kira "harshe mai sanyi" koyaushe yana da sanyi fiye da tafkin mai dumi duk da cewa suna kwance a wannan latitude, yayin da ruwan sanyi ya tashi a can. Girman zafin jiki tsakanin su biyu bi da bi yana haifar da yaduwar yanayi, yaduwar Walker,  wanda ke amsawa da karfi ga gradient na SST. 

Ɗaya daga cikin muhimman bangarorin yanayi shine El Niño-Southern Oscillation (ENSO), yanayin canjin yanayi. A lokacin da yake da kyau / El Niño, ruwa a tsakiya da gabashin Pacific sun fi zafi fiye da yadda aka saba yayin da a lokacin sanyi / La Niña sun fi sanyi fiye da yadda ya saba. Haɗe da waɗannan SST canje-canjen matsin yanayi tsakanin gabashin da yammacin Pacific canje-canje. Bambance-bambance na yaduwar ENSO da Walker suna da tasiri a duniya akan yanayi, gami da bala'o'i irin su gobarar daji, fari, ambaliyar ruwa da aikin Guguwa ta wurare masu zafi. Yankin sararin samaniya yana daidaita yanayin zafi da teku ke ɗauka, ƙarfin da matsayi na Yankin haɗuwa na Intertropical (ITCZ), ruwan sama na wurare masu zafi da ƙarfin Ruwan sama na Indiya.

## Tunanin asali na Clement et al. (1996) da Sun da Liu (1996) da suka gabata
A watan Mayu na shekara ta 1996 Sun da Liu sun buga wani ra'ayi cewa haɗe da hulɗa tsakanin iskar teku, saman teku da ruwan teku na iya iyakance yanayin zafi na ruwa a yammacin Pacific. A matsayin wani ɓangare na wannan binciken, sun gano cewa karuwar yanayin zafi yana haifar da karuwar yanayin zafin jiki tsakanin gabashin da yammacin Pacific.

An bayyana tsarin thermostat na teku a cikin wani littafi da aka keɓe ta Clement et al. 1996 a cikin tsarin haɗin teku-hasken teku na teku. Tun da yake a yammacin Pacific SSTs ne kawai ke sarrafawa ta hanyar adana zafi da zafi, yayin da a gabashin Pacific advection a kwance da tsaye suma suna taka rawa. Don haka tushen da aka tilasta na dumama da farko yana dumama yammacin Pacific, yana haifar da iskõki masu ƙarfi na gabas waɗanda ke sauƙaƙa tashi a gabashin Pacific da sanyaya zafin jikinta - tsarin da ya saba da abin da ake tsammani daga dumama. Ruwa mai sanyi ya tashi tare da ma'auni sannan ya bazu daga gare shi, yana rage jimlar dumama na kwandon. Yanayin zafin jiki tsakanin yamma da gabashin Pacific don haka yana ƙaruwa, yana ƙarfafa iskar kasuwanci kuma yana ƙara haɓaka; wannan a ƙarshe yana haifar da yanayin yanayi mai kama da La Niña. Tsarin yana da yanayi kamar yadda upwelling ba shi da tasiri a cikin bazara kuma ya fi tasiri a cikin kaka; don haka yafi aiki a cikin kaka. Saboda tsarin zafin jiki na tsaye, bambancin ENSO ya zama na yau da kullun yayin sanyaya ta hanyar ma'aunin thermostat, amma an rage shi yayin dumama.

Misali na Clement et al. 1996 kawai yayi la'akari da anomalies na zafin jiki kuma ba ya lissafin duk kasafin kudin makamashi. Bayan ɗan lokaci, dumama zai bazu zuwa yankunan tushen ruwan da aka ɗaga da kuma a cikin thermocline, a ƙarshe ya rage thermostat. Babban kuskuren a cikin samfurin shine cewa yana zaton cewa zafin jiki na ruwan da aka ɗaga baya canzawa a tsawon lokaci.

## Bincike na baya
Nazarin da ya biyo baya ya tabbatar da tsarin thermostat na teku don samfuran yanayi da yawa tare da tsarin zafi daban-daban  da kuma faruwar makamancin amsa - raguwa a cikin SST gradient - don mayar da martani ga sanyaya yanayi.  A cikin cikakkun samfuran da aka haɗa, yanayin yaduwar yanayi don ƙaruwa tare da raguwar insolation wani lokacin yana ƙin amsawar thermostat ga raguwar aikin hasken rana. Liu, Lu da Xie 2015 sun ba da shawarar cewa yanayin zafi na teku na iya aiki a cikin Tekun Indiya, kuma an faɗaɗa manufar don rufe Indo-Pacific gaba ɗaya maimakon kawai Pacific na equatorial.

Ruwa yana gudana daga yammacin Pacific zuwa Tekun Indiya ta hanyar ƙuƙwalwa tsakanin Ostiraliya da Asiya, wani abu da aka sani da Indonesian Throughflow. Rodgers et al. 1999 sun nuna cewa iskar kasuwanci mai karfi da ke da alaƙa da yanayin zafi na teku na iya ƙara bambancin matakin teku tsakanin tekun Indiya da Pacific, ƙara ƙaruwa da sanyaya Pacific. Wani et al. 2022 ya nuna irin wannan sakamako a cikin Tekun Indiya na iya tilasta canje-canje ga Tekun Indiya Dipole bayan Cire carbon dioxide.

## Matsayi a cikin canjin yanayi
An yi amfani da yanayin zafi na teku don bayyana:

* Binciken cewa a lokacin Marine isotope mataki na 3, sanyaya a Greenland yana da alaƙa da El Niño-kamar canjin yanayi a cikin Pacific.
* Raguwar bambancin ENSO a lokacin da ke da babban bambancin hasken rana.
* Canjin zuwa sanyi Interdecadal Pacific Oscillation a ƙarshen karni na 20.

### Tasirin dutsen wuta da hasken rana
An yi amfani da tsarin thermostat na teku don haɗa Fashewar dutse wuta zuwa canje-canjen ENSO. Girgizar dutsen wuta na iya sanyaya Duniya ta hanyar yin allurar aerosols da sulfur dioxide a cikin stratosphere, wanda ke nuna hasken rana mai shigowa. An ba da shawarar cewa a cikin rubuce-rubucen paleoclimate fashewar dutsen wuta sau da yawa ana bin abubuwan da suka faru na El Niño, amma yana da shakku ko wannan ya shafi sanannun fashewar tarihi  kuma sakamakon daga tsarin yanayi ba daidai ba ne.  A wasu samfuran yanayi tsarin thermostat na teku yana haifar da farkon abubuwan da suka faru na El Niño bayan fashewar dutsen wuta, a wasu ƙarin hanyoyin yanayi sun mamaye tasirin thermostat din teku a kan gradients na SST na Pacific.

Tsarin yanayin zafi na teku na iya bayyana bambance-bambance a cikin SSTs na Pacific a gabashin Pacific wanda ke da alaƙa da canje-canjen insolation kamar Dalton Minimum da kuma sake zagayowar hasken rana. A lokacin farkon da tsakiyar Holocene lokacin da aka kara yawan hasken rana a lokacin kaka da rani, amma kuma a lokacin Yanayin Yanayi na Tsakiya tsakanin 900-1300 AD, SSTs daga Baja California a gabashin Pacific sun fi sanyi fiye da yAD aka saba. Kudancin yammacin Arewacin Amurka ya sha wahala sosai a wannan lokacin, wanda kuma zai iya danganta da yanayin La Niña a cikin SSTs na Pacific. Sabanin haka, a lokacin low insolation   kuma a lokacin Little Ice Age SSTs sun karu. Wannan yankin yana cikin California Current wanda ke da tasiri daga gabashin Pacific  wanda ke sarrafa zafin jiki na ruwan da aka ɗaga.  Wannan ya kara tabbatar da shi ta hanyar bincike tare da ƙarin nau'in foraminifera. Ƙarin yawan aiki a cikin ruwan teku daga Peru a lokacin Yanayin Yanayi na Tsakiya Anomaly da Roman Warm Period  tsakanin 50-400 AD, lokacin da yanayin duniya ya fi zafi,  na iya faruwa ta hanyar raguwar thermocline da ke motsawa da kuma karuwar ruwa mai gina jiki.  An gabatar da ƙarin hanyoyin da ke haɗa yanayin yanayin Pacific na equatorial zuwa canje-canjen insolation, duk da haka.

### Matsayi a cikin canjin yanayi na baya-bayan nan
Canje-canje a cikin SSTs na Pacific na equatorial wanda ya haifar da dumamar yanayi ta duniya muhimmiyar matsala ce a cikin hasashen yanayi, yayin da suke tasiri ga tsarin yanayi na gida da na duniya. Ana sa ran tsarin thermostat na teku zai rage yawan zafin jiki na gabashin Pacific dangane da yammacin Pacific, don haka karfafa SST gradient da Walker circulation. Wannan yana adawa da raunanawar yaduwar Walker  da kuma ingantaccen sanyaya na yammacin Pacific a ƙarƙashin dumamar duniya. Wannan diyya tsakanin sakamako daban-daban yana da wahala a kimanta sakamakon ƙarshe na yaduwar Walker da gradient na SST. A cikin samfuran CMIP5 yawanci ba shine tasirin rinjaye ba.

An yi amfani da yanayin zafi na teku don bayyana canje-canje masu sabawa a cikin Tekun Pacific a karni na 20. Musamman, akwai karuwar lokaci guda na gradient na SST, amma kuma rauni na yaduwar Walker musamman a lokacin rani. Duk waɗannan abubuwan lura ba su da tabbas, saboda takamaiman zaɓin ma'auni da aka yi amfani da su don bayyana gradients na SST da ƙarfin yaduwar Walker, da kuma batutuwan ma'aunin da son zuciya. Koyaya, tsarin thermostat na teku na iya bayyana dalilin da ya sa SST gradient ya karu a lokacin dumama duniya  da kuma dalilin da ya ya sa yaduwar Walker ta zama mafi ƙarfi a cikin kaka da hunturu, kamar yadda waɗannan su ne lokutan lokacin da upwelling ya fi karfi.  A gefe guda, dumama a cikin Tekun Atlantika da kuma sauye-sauye gabaɗaya a cikin yanayin zafin jiki na teku na iya taka rawa.

#### Canje-canje na gaba
Misalai na yanayi yawanci suna nuna canjin El Niño, wato raguwa a cikin gradient na SST. A cikin samfuran da yawa, akwai tsari mai dogara da lokaci tare da karuwa na farko a cikin gradient na SST ("amsawa mai sauri") sannan ya biyo bayan rauni na gradient ("amsawa a hankali")  musamman amma ba kawai a cikin yanayin karuwar kwatsam na gas mai ɗorewa ba. Wannan na iya nuna raguwar ƙarfin ƙarfin yanayin zafi na teku tare da karuwar dumama  da dumama ruwan da aka ɗaga, wanda ke faruwa tare da jinkirin 'yan shekarun da suka gabata bayan dumama na saman  kuma an san shi da "ramin teku". A gefe guda, samfuran yanayi na iya rage ƙarfin tasirin thermostat.

* A cewar An da Im 2014, a cikin samfurin tasirin teku ninka sau biyu na carbon dioxide da farko yana sanyaya harshen sanyi na gabashin Pacific, amma ci gaba da karuwa a cikin carbon dioxide a ƙarshe yana haifar da sanyaya ya tsaya kuma harshen sanyi ya ragu. Misali na su ba ya la'akari da canje-canje a cikin zafin jiki na thermocline, wanda zai faru bayan sama da shekaru goma na dumamar duniya.
* A cewar Luo et al. 2017, yanayin zafi na teku a ƙarshe ya shawo kan farko ta hanyar raunana iskar kasuwanci da karuwar rarraba teku wanda ke rage samar da ruwan sanyi zuwa yankunan da ke tasowa,  kuma na biyu ta hanyar isowar ruwan zafi a can.  A cikin samfurin su, sauyawa yana ɗaukar kimanin shekaru goma.
* A cewar Heede, Fedorov da Burls 2020, yanayin zafi mafi girma a waje da wurare masu zafi fiye da ciki ya sa ruwa ya isa yankunan da ke tasowa ya yi dumi  da kuma ruwan teku wanda ke jigilar shi ya raunana. Wannan yana hana tasirin thermostat bayan kimanin shekaru ashirin a cikin yanayin karuwar kwatsam na yawan iskar gas, kuma bayan kimanin rabin zuwa ƙarni daya lokacin da yawan iskar mai ɗorewa ke ƙaruwa a hankali.
* Tare da ci gaba da dumama teku, ana sa ran ƙarfin yanayin zafi na teku zai ragu, saboda raguwar stratification yana nufin cewa ƙarfin ba shi da hankali a cikin farfajiyar kuma ta haka ne hauhawar ta ragu.
* A cewar Heede da Fedorov 2021, a wasu samfuran yanayi tsarin thermostat da farko ya mamaye wasu hanyoyin kuma yana haifar da sanyaya na subtropical da tsakiyar Pacific. A ƙarshe yawancin samfuran sun haɗu da tsarin dumama na equatorial.
* Zhou et al. 2022 sun gano cewa a cikin yanayin Cire carbon dioxide, thermostat yana kara sauye-sauyen hazo.
* Zheng et al. 2024 sun danganta canje-canje na yanayi na SST tare da dumama duniya ga tasirin thermostat.

## Sauran mahallin
An kuma yi amfani da kalmar "ma'aunin zafi na teku" a cikin mahallin daban-daban:

* Ma'amala tsakanin raunin Walker da ke raguwa da kuma Equatorial Undercurrent.  Musamman, iska mai rauni na gabas a cikin Pacific yana rage ƙuntatawar Undercurrent, don haka yana hanzarta shi. Wannan tsari ya mamaye raguwar gabas na Undercurrent. Don haka, yaduwar Walker mai rauni na iya kara yawan kwararar Undercurrent kuma ta haka ne ya tashi a gabashin Pacific, ya sanyaya shi. Misalai masu juyawa sau da yawa ba sa nuna wannan martani na gradients na Undercurrent da SST daidai; tsohon na iya zama dalilin yaduwar rashin daidaituwa na gradients ɗin SST a cikin waɗannan samfuran.
* Iska mai karfi tana fitar da sanyaya mai zafi na SST na wurare masu zafi.
* A cewar Heede, Fedorov da Burls 2020, don mayar da martani ga karuwar kwatsam a cikin iskar gas mai tsabta mai rauni yana ba da damar Tekun Indiya ya fi zafi fiye da Tekun Pacific. Wannan yana haifar da iskar gabas mai ƙarfi a kan Pacific wanda ya kara rage zafi a cikin Tekun Pacific. Ba kamar yanayin zafi na teku ba duk da haka wannan tasirin sanyaya yana mai da hankali a tsakiyar gabashin Pacific, yayin da iskõki na yamma da aka haifar da dumama a kan Kudancin Amurka ke haifar da gabashin Pacific ya yi dumi.

## Manazarta