Tsinkaye na shekaru goma na Pacific
 Tsinkaye na shekaru goma na Pacific | |
|---|---|
oscillation (en)  da meteorological phenomenon (en) |
Pacific decadal oscillation (PDO) mai ƙarfi ne, tsarin maimaitawa na canjin yanayi na teku da ke tsakiya a tsakiyar tsakiyar yankin Pacific. Ana gano PDO a matsayin ruwan dumi ko sanyi a cikin Tekun Pacific, arewacin 20 ° N. A cikin ƙarni da ya gabata, girman wannan yanayin yanayi ya bambanta ba bisa ka'ida ba a sikelin lokaci na shekara-shekara zuwa shekaru-shekaru (ma'ana lokutan lokaci na 'yan shekaru zuwa kusan lokutan lokaci da yawa). Akwai shaidar juyawa a cikin polarity mai yawa (ma'ana canje-canje a cikin ruwan sanyi da ruwan dumi a cikin yankin) na oscillation da ke faruwa a kusa da 1925, 1947, da 1977; juyawa biyu na ƙarshe sun dace da sauye-sauye masu ban mamaki a cikin Tsarin samar da salmon a Arewacin Tekun Pacific. Wannan yanayin yanayi kuma yana shafar yanayin teku na bakin teku da yanayin iska na nahiyar daga Alaska zuwa California.
A lokacin "mai dumi", ko "mai kyau", lokaci, yammacin Pacific ya zama mai sanyi kuma wani ɓangare na gabashin teku yana dumi; a lokacin "mai sanyi", ko "matsayi", lokaci, akasin haka yana faruwa. Steven R. Hare ne ya ba da sunan oscillation na shekaru goma na Pacific, wanda ya lura da shi yayin da yake nazarin sakamakon samar da salmon a shekarar 1997. [1]
Alamar oscillation na Pacific decadal ita ce babbar aikin orthogonal (EOF) na yanayin zafin jiki na teku na kowane wata (SST-A) a Arewacin Pacific (poleward na 20 ° N) bayan an cire matsakaicin zafin teku na duniya. Wannan alamar PDO ita ce daidaitattun jerin lokuta.[2] An sake gina 'signal' na PDO har zuwa 1661 ta hanyar jerin lokuta na bishiyoyi a yankin Baja California.[3]
Hanyoyin da ake amfani da su
[gyara sashe | gyara masomin]Bincike da yawa sun nuna cewa za'a iya sake gina alamar PDO a matsayin ƙaddamar da tilasta wa wurare masu zafi da kuma matakai na wurare masu zafi.[4][5][6][7] Don haka, ba kamar El Niño-Southern Oscillation (ENSO) ba, PDO ba yanayin jiki ɗaya ne na bambancin teku, amma jimlar matakai da yawa tare da asali daban-daban.
A ma'auni na lokaci-shekara ana sake gina alamar PDO a matsayin jimlar bazuwar da ENSO ya haifar da bambancin a cikin Aleutian Low, yayin da a kan ma'aunin lokaci na ENSO, tilasta yanayin yanayi da canje-canje a cikin Yankin Tekun Arewacin Pacific suna ba da gudummawa kusan daidai. Bugu da ƙari, Yanayin zafin jiki na teku yana da wasu hunturu zuwa hunturu saboda tsarin sake fitowa.
Tasirin
[gyara sashe | gyara masomin]Tsarin sararin samaniya na PDO da tasirin suna kama da waɗanda ke da alaƙa da abubuwan da suka faru na ENSO. A lokacin da ya dace, lokacin hunturu na Aleutian Low yana zurfafawa kuma ya koma kudu, iska mai dumi / mai zafi yana gudana tare da gabar yammacin Arewacin Amurka kuma yanayin zafi ya fi na yau da kullun daga Arewa maso Yammacin Pacific zuwa Alaska amma a ƙasa da al'ada a Mexico da Kudu maso gabashin Amurka. Ruwan sama na hunturu ya fi na yau da kullun a cikin Alaska Coast Range, Mexico da Kudu maso Yammacin Amurka amma ya ragu a kan Kanada, Gabashin Siberia da Australia [8] McCabe et al.[9][10] ya nuna cewa PDO tare da AMO suna da tasiri sosai ga tsarin fari na shekaru da yawa a Amurka, ana inganta yawan fari a yawancin Arewacin Amurka a lokacin PDO mai kyau da kuma Kudu maso Yammacin Amurka a yayin mummunan PDO a lokuta biyu idan PDO yana da alaƙa da AMO mai kyau. Hakanan yana shafar ruwan sama na Asiya, ana lura da ruwan sama da raguwar zafin lokacin rani a kan yankin Indiya a lokacin mummunan lokaci.[11]
| Alamun PDO | Matsayi mai kyau na PDO | Mataki mara kyau na PDO |
|---|---|---|
| Yanayin zafi | ||
| Pacific Northwest, British Columbia, da Alaska | Sama da matsakaici | Da ke ƙasa da matsakaici |
| Mexico zuwa Kudu maso Gabashin Amurka | Da ke ƙasa da matsakaici | Sama da matsakaici |
| Ruwan sama | ||
| Yankin bakin teku na Alaska | Sama da matsakaici | Da ke ƙasa da matsakaici |
| Mexico zuwa Kudu maso Yammacin Amurka | Sama da matsakaici | Da ke ƙasa da matsakaici |
| Kanada, Gabashin Siberia da Ostiraliya | Da ke ƙasa da matsakaici | Sama da matsakaici |
| Lokacin bazara na Indiya | Da ke ƙasa da matsakaici | Sama da matsakaici |
Manazarta
[gyara sashe | gyara masomin]- ↑ Mantua, Nathan J.; Hare, Steven R.; Zhang, Yuan; Wallace, John M.; Francis, Robert C. (1997). "A Pacific interdecadal climate oscillation with impacts on salmon production". Bulletin of the American Meteorological Society. 78 (6): 1069–79. Bibcode:1997BAMS...78.1069M. doi:10.1175/1520-0477(1997)078<1069:APICOW>2.0.CO;2.
- ↑ Deser, Clara; Alexander, Michael A.; Xie, Shang-Ping; Phillips, Adam S. (January 2010). "Sea Surface Temperature Variability: Patterns and Mechanisms". Annual Review of Marine Science. 2 (1): 115–143. Bibcode:2010ARMS....2..115D. doi:10.1146/annurev-marine-120408-151453. PMID 21141660.
- ↑ Biondi, Franco; Gershunov, Alexander; Cayan, Daniel R. (2001). "North Pacific Decadal Climate Variability since 1661". Journal of Climate. 14 (1): 5–10. Bibcode:2001JCli...14....5B. doi:10.1175/1520-0442(2001)014<0005:NPDCVS>2.0.CO;2. Archived from the original on December 14, 2012.
- ↑ Newman, M.; Compo, G.P.; Alexander, Michael A. (2003). "ENSO-Forced Variability of the Pacific Decadal Oscillation". Journal of Climate. 16 (23): 3853–7. Bibcode:2003JCli...16.3853N. doi:10.1175/1520-0442(2003)016<3853:EVOTPD>2.0.CO;2. S2CID 17779179.
- ↑ Vimont, Daniel J. (2005). "The Contribution of the Interannual ENSO Cycle to the Spatial Pattern of Decadal ENSO-Like Variability". Journal of Climate. 18 (12): 2080–92. Bibcode:2005JCli...18.2080V. doi:10.1175/JCLI3365.1.
- ↑ Schneider, Niklas; Bruce D. Cornuelle (2005). "The Forcing of the Pacific Decadal Oscillation". Journal of Climate. 18 (8): 4355–72. Bibcode:2005JCli...18.4355S. doi:10.1175/JCLI3527.1. S2CID 34236797.
- ↑ Qiu, Bo; Niklas Schneider; Shuiming Chen (2007). "Coupled Decadal Variability in the North Pacific: An Observationally Constrained Idealized Model". Journal of Climate. 20 (14): 3602–20. Bibcode:2007JCli...20.3602Q. doi:10.1175/JCLI4190.1.
- ↑ Cite error: Invalid
<ref>tag; no text was provided for refs namedMantua20022 - ↑ Power, S.; et al. (1998). "Australian temperature, Australian rainfall and the Southern Oscillation, 1910-1992: coherent variability and recent changes" (PDF). Australian Meteorological Magazine. 47 (2): 85–101. Archived from the original (PDF) on 27 April 2020. Retrieved 8 April 2013.
- ↑ McCabe, G. J.; Palecki, M. A.; Betancourt, J. L. (11 March 2004). "Pacific and Atlantic Ocean influences on multidecadal drought frequency in the United States". Proceedings of the National Academy of Sciences. 101 (12): 4136–41. Bibcode:2004PNAS..101.4136M. doi:10.1073/pnas.0306738101. PMC 384707. PMID 15016919.
- ↑ Krishnan, R.; Sugi, M. (31 August 2003). "Pacific decadal oscillation and variability of the Indian summer monsoon rainfall". Climate Dynamics. 21 (3–4): 233–242. Bibcode:2003ClDy...21..233K. doi:10.1007/s00382-003-0330-8. S2CID 140557286.