Impact of lower stratospheric ozone on seasonal prediction systems

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dc.contributor.author Mathole, Kelebogile
dc.contributor.author Ndarana, Thando
dc.contributor.author Beraki, Asmerom Fissehatsion
dc.contributor.author Landman, W.A. (Willem Adolf), 1964-
dc.date.accessioned 2014-08-18T09:52:17Z
dc.date.available 2014-08-18T09:52:17Z
dc.date.issued 2014-03
dc.description.abstract We 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.librarian am2014 en_US
dc.description.sponsorship The Water Research Commission (project number K5/1913) and the Applied Centre for Climate and Earth Systems Science. en_US
dc.description.uri http://www.sajs.co.za en_US
dc.identifier.citation Mathole 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.issn 0038-2353 (print)
dc.identifier.issn 1996-7489 (online)
dc.identifier.other 10.1590/sajs.2014/20130161
dc.identifier.uri http://hdl.handle.net/2263/41400
dc.language.iso en en_US
dc.publisher AOSIS Open Journals en_US
dc.rights © 2014. The Authors. Published under a Creative Commons Attribution Licence. en_US
dc.subject Polar vortex en_US
dc.subject Eddy-driven jet en_US
dc.subject Stratosphere en_US
dc.subject Ozone depletion en_US
dc.subject El Nino Southern Oscillation (ENSO) en_US
dc.subject Oceanatmospheric general circulation model (OAGCM) en_US
dc.title Impact of lower stratospheric ozone on seasonal prediction systems en_US
dc.type Article en_US


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