Forecasting seasonal rainfall characteristics and onset months over South Africa

dc.contributor.authorPhakula, Steven
dc.contributor.authorLandman, Willem Adolf
dc.contributor.authorBeraki, Asmerom Fissehatsion
dc.date.accessioned2018-02-14T11:46:46Z
dc.date.issued2018-04
dc.description.abstractAspects of forecast skill in predicting seasonal characteristics using global climate models (GCMs) are assessed over South Africa. The GCMs output is configured to predict number of rainfall days at South African Weather Service stations exceeding pre-defined threshold values for the austral summer seasons and to predict the rainfall totals of the onset months of the rainy seasons for eight homogeneous rainfall regions of South Africa. Using canonical correlation analysis (CCA) as statistical downscaling technique through model output statistics, the forecast skill levels of coupled ocean–atmosphere and uncoupled atmospheric models are determined through retro-actively generated hindcasts. Both downscaled models have skill in predicting low and high number of rainfall days exceeding pre-defined thresholds for the austral summer seasons as well as rainfall totals of onset months. In addition to the forecast verification results, CCA pattern is performed to determine the dominating atmospheric circulation systems predicted to be controlling rainfall variations for the seasons and months of interest. CCA patterns for both the GCMs indicate that usually when there are anomalously negative (positive) predicted 850 hPa geopotential heights over South Africa, there are anomalously wet (dry) conditions over most parts of South Africa. The work has paved the way for the operational production of seasonal rainfall characteristics over South Africa in real time.en_ZA
dc.description.departmentGeography, Geoinformatics and Meteorologyen_ZA
dc.description.embargo2019-04-01
dc.description.librarianhj2018en_ZA
dc.description.sponsorshipThe Department of Trade and Industry through Applied Centre for Climate and Earth Systems Science (ACCESS) and the South African Weather Service.en_ZA
dc.description.urihttp://onlinelibrary.wiley.com/journal/10.1002/(ISSN)1097-0088en_ZA
dc.identifier.citationPhakula, S., Landman, W. A. and Beraki, A. F. (2018), Forecasting seasonal rainfall characteristics and onset months over South Africa. International Journal of Climatology, vol. 38, no. S1, pp. e889-e900, doi:10.1002/joc.5417.en_ZA
dc.identifier.issn0899-8418 (print)
dc.identifier.issn1097-0088 (online)
dc.identifier.other10.1002/joc.5417
dc.identifier.urihttp://hdl.handle.net/2263/63954
dc.language.isoenen_ZA
dc.publisherWileyen_ZA
dc.rights© 2018 Royal Meteorological Society. This is the pre-peer reviewed version of the following article : Forecasting seasonal rainfall characteristics and onset months over South Africa in International Journal of Climatology, vol. vol. 38, no. S1, pp. e889-e900, 2018. doi : 10.1002/joc.5417 which has been published in final form at : http://onlinelibrary.wiley.comjournal/10.1002/(ISSN)1097-0088.en_ZA
dc.subjectGlobal climate models (GCMs)en_ZA
dc.subjectCanonical correlation analysis (CCA)en_ZA
dc.subjectForecast verificationen_ZA
dc.subjectRetro-active hindcastsen_ZA
dc.subjectStatistical downscalingen_ZA
dc.subjectSeasonal rainfall characteristicsen_ZA
dc.subjectClimate modelsen_ZA
dc.subjectRainen_ZA
dc.subjectWeather forecastingen_ZA
dc.subjectForecastingen_ZA
dc.subjectModel output statisticsen_ZA
dc.subjectHindcastsen_ZA
dc.subjectAtmospheric circulationen_ZA
dc.titleForecasting seasonal rainfall characteristics and onset months over South Africaen_ZA
dc.typePostprint Articleen_ZA

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