Trends in Austral jet position in ensembles of high- and low-top CMIP5 models
Trends in the position of the DJF Austral jet have been analyzed for multimodel ensemble simulations of a subset of high- and low-top models for the periods 1960-2000, 2000-2050, and 2050-2098 under the CMIP5 historical, RCP4.5, and RCP8.5 scenarios. Comparison with ERA-Interim, CFSR and the NCEP/NC...
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| Format: | Journal article |
| Language: | English |
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2012
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| _version_ | 1826258306075721728 |
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| author | Wilcox, L Charlton-Perez, A Gray, L |
| author_facet | Wilcox, L Charlton-Perez, A Gray, L |
| author_sort | Wilcox, L |
| collection | OXFORD |
| description | Trends in the position of the DJF Austral jet have been analyzed for multimodel ensemble simulations of a subset of high- and low-top models for the periods 1960-2000, 2000-2050, and 2050-2098 under the CMIP5 historical, RCP4.5, and RCP8.5 scenarios. Comparison with ERA-Interim, CFSR and the NCEP/NCAR reanalysis shows that the DJF and annual mean jet positions in CMIP5 models are equatorward of reanalyses for the 1979-2006 mean. Under the RCP8.5 scenario, the mean jet position in the high-top models moves 3 degrees poleward of its 1860-1900 position by 2098, compared to just over 2 degrees for the low-top models. Changes in jet position are linked to changes in the meridional temperature gradient. Compared to low-top models, the high-top models predict greater warming in the tropical upper troposphere due to increased greenhouse gases for all periods considered: up to 0.28K/decade more in the period 2050-2098 under the RCP8.5 scenario. Larger polar lower-stratospheric cooling is seen in high-top models: -1.64K/decade compared to -1.40K/decade in the period 1960-2000, mainly in response to ozone depletion, and -0.41K/decade compared to -0.12K/decade in the period 2050-2098, mainly in response to increases in greenhouse gases. Analysis suggests that there may be a linear relationship between the trend in jet position and meridional temperature gradient, even under strong forcing. There were no clear indications of an approach to a geometric limit on the absolute magnitude of the poleward shift by 2100. © 2012. American Geophysical Union. All Rights Reserved. |
| first_indexed | 2024-03-06T18:31:54Z |
| format | Journal article |
| id | oxford-uuid:09edce5b-bfb6-41ba-80ef-d0d07cf40ef1 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-06T18:31:54Z |
| publishDate | 2012 |
| record_format | dspace |
| spelling | oxford-uuid:09edce5b-bfb6-41ba-80ef-d0d07cf40ef12022-03-26T09:21:05ZTrends in Austral jet position in ensembles of high- and low-top CMIP5 modelsJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:09edce5b-bfb6-41ba-80ef-d0d07cf40ef1EnglishSymplectic Elements at Oxford2012Wilcox, LCharlton-Perez, AGray, LTrends in the position of the DJF Austral jet have been analyzed for multimodel ensemble simulations of a subset of high- and low-top models for the periods 1960-2000, 2000-2050, and 2050-2098 under the CMIP5 historical, RCP4.5, and RCP8.5 scenarios. Comparison with ERA-Interim, CFSR and the NCEP/NCAR reanalysis shows that the DJF and annual mean jet positions in CMIP5 models are equatorward of reanalyses for the 1979-2006 mean. Under the RCP8.5 scenario, the mean jet position in the high-top models moves 3 degrees poleward of its 1860-1900 position by 2098, compared to just over 2 degrees for the low-top models. Changes in jet position are linked to changes in the meridional temperature gradient. Compared to low-top models, the high-top models predict greater warming in the tropical upper troposphere due to increased greenhouse gases for all periods considered: up to 0.28K/decade more in the period 2050-2098 under the RCP8.5 scenario. Larger polar lower-stratospheric cooling is seen in high-top models: -1.64K/decade compared to -1.40K/decade in the period 1960-2000, mainly in response to ozone depletion, and -0.41K/decade compared to -0.12K/decade in the period 2050-2098, mainly in response to increases in greenhouse gases. Analysis suggests that there may be a linear relationship between the trend in jet position and meridional temperature gradient, even under strong forcing. There were no clear indications of an approach to a geometric limit on the absolute magnitude of the poleward shift by 2100. © 2012. American Geophysical Union. All Rights Reserved. |
| spellingShingle | Wilcox, L Charlton-Perez, A Gray, L Trends in Austral jet position in ensembles of high- and low-top CMIP5 models |
| title | Trends in Austral jet position in ensembles of high- and low-top CMIP5 models |
| title_full | Trends in Austral jet position in ensembles of high- and low-top CMIP5 models |
| title_fullStr | Trends in Austral jet position in ensembles of high- and low-top CMIP5 models |
| title_full_unstemmed | Trends in Austral jet position in ensembles of high- and low-top CMIP5 models |
| title_short | Trends in Austral jet position in ensembles of high- and low-top CMIP5 models |
| title_sort | trends in austral jet position in ensembles of high and low top cmip5 models |
| work_keys_str_mv | AT wilcoxl trendsinaustraljetpositioninensemblesofhighandlowtopcmip5models AT charltonpereza trendsinaustraljetpositioninensemblesofhighandlowtopcmip5models AT grayl trendsinaustraljetpositioninensemblesofhighandlowtopcmip5models |