Impact of lower stratospheric ozone on seasonal prediction systems

dc.contributor.authorMathole, Kelebogile
dc.contributor.authorNdarana, Thando
dc.contributor.authorBeraki, Asmerom Fissehatsion
dc.contributor.authorLandman, Willem Adolf
dc.date.accessioned2014-08-18T09:52:17Z
dc.date.available2014-08-18T09:52:17Z
dc.date.issued2014-03
dc.description.abstractWe conducted a comparison of trends in lower stratospheric temperatures and summer zonal wind fields based on 27 years of reanalysis data and output from hindcast simulations using a coupled oceanatmospheric general circulation model (OAGCM). Lower stratospheric ozone in the OAGCM was relaxed to the observed climatology and increasing greenhouse gas concentrations were neglected. In the reanalysis, lower stratospheric ozone fields were better represented than in the OAGCM. The spring lower stratospheric/ upper tropospheric cooling in the polar cap observed in the reanalysis, which is caused by a direct ozone depletion in the past two decades and is in agreement with previous studies, did not appear in the OAGCM. The corresponding summer tropospheric response also differed between data sets. In the reanalysis, a statistically significant poleward trend of the summer jet position was found, whereas no such trend was found in the OAGCM. Furthermore, the jet position in the reanalysis exhibited larger interannual variability than that in the OAGCM. We conclude that these differences are caused by the absence of long-term lower stratospheric ozone changes in the OAGCM. Improper representation or non-inclusion of such ozone variability in a prediction model could adversely affect the accuracy of the predictability of summer rainfall forecasts over South Africa.en_US
dc.description.librarianam2014en_US
dc.description.sponsorshipThe Water Research Commission (project number K5/1913) and the Applied Centre for Climate and Earth Systems Science.en_US
dc.description.urihttp://www.sajs.co.zaen_US
dc.identifier.citationMathole K, Ndarana T, Beraki A, Landman W. Impact of lower stratospheric ozone on seasonal prediction systems. S Afr J Sci. 2014;110(3/4), Art. #2013-0161, 8 pages. http://dx.DOI.org/ 10.1590/sajs.2014/20130161.en_US
dc.identifier.issn0038-2353 (print)
dc.identifier.issn1996-7489 (online)
dc.identifier.other10.1590/sajs.2014/20130161
dc.identifier.urihttp://hdl.handle.net/2263/41400
dc.language.isoenen_US
dc.publisherAOSIS Open Journalsen_US
dc.rights© 2014. The Authors. Published under a Creative Commons Attribution Licence.en_US
dc.subjectPolar vortexen_US
dc.subjectEddy-driven jeten_US
dc.subjectStratosphereen_US
dc.subjectOzone depletionen_US
dc.subjectEl Nino Southern Oscillation (ENSO)en_US
dc.subjectOceanatmospheric general circulation model (OAGCM)en_US
dc.titleImpact of lower stratospheric ozone on seasonal prediction systemsen_US
dc.typeArticleen_US

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