Duniyar terrestrial stilling

**Tsayar da ƙasa a duniya** shine raguwar saurin iska da aka gani kusa da saman duniya (~ tsayin mita 10) a cikin shekaru talatin da suka gabata (musamman tun shekarun 1980), wanda asalinsa ake kira "tsitsi".  Wannan raguwar iskar ƙasa da ke kusa da ƙasa ta fi shafar yankunan tsakiyar latitude na duka sassan duniya, tare da raguwar matsakaicin duniya na -0.140&nbsp;ms -1 dec -1 (mitoci a sakan daya a kowace shekara goma) ko tsakanin 5 da 15% a cikin shekaru 50 da suka gabata.  Tare da babban-latitude (> 75° daga ma'auni) yana nuna haɓaka a cikin duka hemispheres. Sabanin yadda iskoki ke yin rauni a saman nahiyoyin duniya, iskoki sun yi ƙoƙarin yin ƙarfi a kan yankunan teku .   A cikin 'yan shekarun da suka gabata, an gano raguwa a cikin wannan raguwar saurin iska wanda ke nuna farfadowa a ma'aunin duniya tun daga 2013. 

Haƙiƙanin dalilin (s) na wanzuwar ƙasa a duniya ba shi da tabbas kuma an danganta shi da manyan direbobi guda biyu: (i) canje-canje a cikin yanayin yanayin yanayi mai girma, da (ii) haɓakar yanayin ƙasa saboda girma daji, amfani da ƙasa. canje-canje, da ƙauyuka .

Bayar da canjin yanayi, canje-canje a cikin saurin iska a halin yanzu yana da yiwuwar damuwa ga jama'a, saboda tasirin da hydrology , da hydrologicals, da iska mai ƙarfi, ko , ko ingancin iska da lafiyar dan Adam, da dai sauransu.

## Dalilai
Asalin wannan rauni na saurin iskar kusa da saman ƙasa ba cikakke ba ne, mai yiwuwa saboda dalilai da yawa waɗanda ke hulɗa a lokaci ɗaya, kuma suna iya canzawa a sararin samaniya cikin lokaci. Masana kimiyya sun yi nuni da manyan dalilai daban-daban da ke tasiri wannan raguwar saurin iska:

(i) Haɓaka rashin ƙarfi na ƙasa (misali girma gandun daji, sauye-sauyen amfani da ƙasa da ƙauyuka) kusa da tashar yanayin yanayi inda kayan aikin anemometer ke kaiwa ga ƙarfin juzu'i wanda ke raunana ƙananan iska.   

(ii) Bambance-bambancen yanayi mai girma, wanda ke da alaƙa da fadada poleward na tantanin halitta Hadley  da kuma sauyawar cibiyoyin ayyuka (watau anticyclones da cyclones ) suna sarrafa canje-canje a cikin saurin iska na kusa.   

(iii) Canje-canjen yadda ake auna saurin iskar, gami da tabarbarewar kayan aiki na na'urorin anemometer; inganta fasaha na anemometers; tsayin anemometer;  canzawa a wuraren ma'auni; canje-canje a cikin yanayi a kusa da tashar sa ido; al'amurran daidaitawa ; da kuma auna tazarar lokaci. 

(iv) The " duniya dimming ", watau, raguwa a cikin adadin hasken rana radiation isa zuwa doron kasa saboda ƙara aerosol da kuma greenhouse gas taro, tilasta a tabbatar da yanayi haifar da rauni iska. 

(v) Wasu dalilai, kamar haɓaka yanayin damshin ƙasa da ake samu  da sauye-sauye na sararin samaniya  an gabatar da su gaba.

Duk da haka, har yanzu ba a warware ainihin abubuwan da ke haifar da dawwama a duniya ba saboda yawancin rashin tabbas da ke tattare da wannan lamari a fadin duniya.

## Rashin tabbas
"Tsarin duniya" ba ya yin tasiri kamar yadda dukan sararin duniya ke fadin ƙasa da saman teku. A sararin samaniya, an ba da rahoton karuwar saurin iska ga wasu yankuna, musamman ga manyan latitudes,  bakin teku  da kuma saman teku inda marubuta daban-daban    suka tabbatar da karuwar yanayin duniya. gudun iska ta amfani da ma'aunin tauraron dan adam a cikin shekaru 30-40 da suka gabata. Binciken da aka yi kwanan nan ya nuna raguwa a cikin mummunan hali na saurin iskar ƙasa, tare da farfadowa da yawa na kwanan nan / ƙarfafa saurin iska tun a kusa da 2013.   Wannan yana haifar da rashin tabbas a fahimtar lamarin.

Yawancin rashin tabbas da ke bayan muhawarar "ƙaddarar duniya" tana zaune a cikin (i) gajeriyar isar da bayanan saurin iskar, tare da jerin farawa a cikin 1960s, (ii) nazarin saurin iskar da aka fi aiwatar da shi akan yankuna na tsakiya inda yawancin ma'auni na dogon lokaci. akwai;  da (iii) ƙarancin ingancin rikodin anemometer kamar yadda rahoton kimantawa na biyar (AR5) ya nuna na Ƙungiyar gwamnatoci kan Canjin Yanayi (IPCC).

Karancin inganci a cikin jerin saurin iska ya samo asali ne saboda abubuwan da ba na yanayi ba (misali lura da sauye-sauyen aiki, ƙaura tasha, canjin tsayin anemometer) yana shafar waɗannan bayanan, wanda ke haifar da zama mara wakilci na ainihin bambance-bambancen saurin iska na tsawon lokaci. An haɓaka ƙayyadaddun ƙa'idodin homogenization don jerin saurin iska don ganowa da daidaita yuwuwar inhomogeneities. 

## Bincike mai gudana
Binciken da ake yi a halin yanzu game da tantancewa da kuma danganta wannan lamarin ya mayar da hankali kan rage ƙayyadaddun samuwa da ƙarancin ingancin bayanan saurin iska. Aikin binciken da Turai ta tallafa wa STILLING  wani shiri ne na yanzu (2016-2018) wanda ke da nufin rage wannan takurawa ta hanyar ceto, daidaitawa da dawo da mafi tsayi kuma mafi inganci jerin saurin iska a duk faɗin duniya. A halin yanzu aikin yana tattara bayanan saurin iska wanda ya fara a cikin 1880 yana ba masana kimiyya kusan bayanan shekaru 130, kusan shekaru 80 fiye da karatun baya da ake samu a cikin adabin kimiyya. Ingantacciyar masaniyar yanayin saurin iskar da ta gabata yana da mahimmanci don fahimtar abin da ke faruwa a halin yanzu na "zamantakewar duniya", gano idan sauyin yanayi ya biyo bayan wannan guguwar iska ko kuma irin wannan yanayin da ya faru a baya kuma ana iya sa ran nan gaba. Wato tare da dogon rikodin za a iya gano zagayowar decadal.

## Abubuwan canjin saurin iska
Al'amarin "kwarjinin duniya" yana da babban sha'awar kimiyya, tattalin arziki, da muhalli saboda mahimmin tasirin ko da ƙananan saurin iskar da ke sauye-sauye a yanayin yanayi da yanayin teku da sauran fannonin da ke da alaƙa kamar: (i) makamashin iska mai sabuntawa;  (ii) noma da ilimin ruwa saboda ƙawance;  (iii) ƙaura na nau'in tsire-tsire masu watsar da iska;  (iv) bala'o'in da suka shafi iska;  (v) Tasirin ruwa da bakin teku saboda guguwar da iska ke haifarwa da raƙuman ruwa;  (vi) watsar da gurɓataccen iska;  a tsakanin sauran fannonin tattalin arziki da muhalli da yawa. Duk da haka, don makamashin iska kusa da saman sararin sama ana lura da saurin iska a cikin 10m na filin ƙasa, kuma tare da injin turbin da aka samo wasu 60-80.&nbsp;m sama da ƙasa ana buƙatar ƙarin karatu a nan. Ana kuma buƙatar ƙarin karatu a wurare masu tsayi, waɗanda galibi yankuna ne waɗanda ke samar da yawancin kayan ruwan mu, da ake kira hasumiya na ruwa,   kamar yadda saurin iska ya nuna yana raguwa da sauri fiye da canje-canjen da aka rubuta a. ƙananan wuraren tsaunuka,  kuma akwai takardun Sinanci da yawa da ke nuna wannan ga Tibet Plateau. 

## Nassoshi