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Seasonal rainfall predictability over the Lake Kariba catchment area

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dc.contributor.author Muchuru, S
dc.contributor.author Landman, WA
dc.contributor.author DeWitt, D
dc.contributor.author Lötter, D
dc.date.accessioned 2014-08-20T08:52:09Z
dc.date.available 2014-08-20T08:52:09Z
dc.date.issued 2014-07
dc.identifier.citation Muchuru, S, Landman, W.A, DeWitt, D and Lötter, D. 2014. Seasonal rainfall predictability over the Lake Kariba catchment area. Water SA, vol. 40(3), pp 461-470 en_US
dc.identifier.issn 0378-4738
dc.identifier.uri http://www.wrc.org.za/Pages/Preview.aspx?ItemID=10813&FromURL=%2fPages%2fDisplayItem.aspx%3fItemID%3d10813%26FromURL%3d%252fPages%252fDefault.aspx%253fdt%253d%2526ms%253d%2526d%253dSeasonal%2brainfall%2bpredictability%2bover%2bthe%2bLake%2bKariba%2bcatchment%2barea%2b%2526start%253d1
dc.identifier.uri http://hdl.handle.net/10204/7618
dc.description Copyright: 2014 Water Research Commission. Published in Water SA, vol 40(3), pp 461-470 en_US
dc.description.abstract The Lake Kariba catchment area in southern Africa has one of the most variable climates of any major river basin, with an extreme range of conditions across the catchment and through time. Marked seasonal and interannual fluctuations in rainfall are a significant aspect of the catchment. To determine the predictability of seasonal rainfall totals over the Lake Kariba catchment area, this study used the low-level atmospheric circulation (850 hPa geopotential height fields) of a coupled ocean-atmosphere general circulation model (CGCM) over southern Africa, statistically downscaled to gridded seasonal rainfall totals over the catchment. This downscaling configuration was used to retroactively forecast the 3-month rainfall seasons of September-October-November through February-March-April, over a 14-year independent test period extending from 1994. Retroactive forecasts are produced for lead times of up to 5 months and probabilistic forecast performances evaluated for extreme rainfall thresholds of the 25th and 75th percentile values of the climatological record. The verification of the retroactive forecasts shows that rainfall over the catchment is predictable at extended lead-times, but that predictability is primarily found for austral mid-summer rainfall. This season is also associated with the highest potential economic value that can be derived from seasonal forecasts. A forecast case study of a recent extreme rainfall season (2010/11) that lies outside of the verification period is presented as evidence of the statistical downscaling system’s operational capability. en_US
dc.language.iso en en_US
dc.publisher Water Research Commission en_US
dc.relation.ispartofseries Workflow;13285
dc.subject Lake Kariba catchment area en_US
dc.subject Rainfall fluctuations en_US
dc.subject Seasonal rainfall predictability en_US
dc.subject Rainfall forecasts en_US
dc.title Seasonal rainfall predictability over the Lake Kariba catchment area en_US
dc.type Article en_US
dc.identifier.apacitation Muchuru, S., Landman, W., DeWitt, D., & Lötter, D. (2014). Seasonal rainfall predictability over the Lake Kariba catchment area. http://hdl.handle.net/10204/7618 en_ZA
dc.identifier.chicagocitation Muchuru, S, WA Landman, D DeWitt, and D Lötter "Seasonal rainfall predictability over the Lake Kariba catchment area." (2014) http://hdl.handle.net/10204/7618 en_ZA
dc.identifier.vancouvercitation Muchuru S, Landman W, DeWitt D, Lötter D. Seasonal rainfall predictability over the Lake Kariba catchment area. 2014; http://hdl.handle.net/10204/7618. en_ZA
dc.identifier.ris TY - Article AU - Muchuru, S AU - Landman, WA AU - DeWitt, D AU - Lötter, D AB - The Lake Kariba catchment area in southern Africa has one of the most variable climates of any major river basin, with an extreme range of conditions across the catchment and through time. Marked seasonal and interannual fluctuations in rainfall are a significant aspect of the catchment. To determine the predictability of seasonal rainfall totals over the Lake Kariba catchment area, this study used the low-level atmospheric circulation (850 hPa geopotential height fields) of a coupled ocean-atmosphere general circulation model (CGCM) over southern Africa, statistically downscaled to gridded seasonal rainfall totals over the catchment. This downscaling configuration was used to retroactively forecast the 3-month rainfall seasons of September-October-November through February-March-April, over a 14-year independent test period extending from 1994. Retroactive forecasts are produced for lead times of up to 5 months and probabilistic forecast performances evaluated for extreme rainfall thresholds of the 25th and 75th percentile values of the climatological record. The verification of the retroactive forecasts shows that rainfall over the catchment is predictable at extended lead-times, but that predictability is primarily found for austral mid-summer rainfall. This season is also associated with the highest potential economic value that can be derived from seasonal forecasts. A forecast case study of a recent extreme rainfall season (2010/11) that lies outside of the verification period is presented as evidence of the statistical downscaling system’s operational capability. DA - 2014-07 DB - ResearchSpace DP - CSIR KW - Lake Kariba catchment area KW - Rainfall fluctuations KW - Seasonal rainfall predictability KW - Rainfall forecasts LK - https://researchspace.csir.co.za PY - 2014 SM - 0378-4738 T1 - Seasonal rainfall predictability over the Lake Kariba catchment area TI - Seasonal rainfall predictability over the Lake Kariba catchment area UR - http://hdl.handle.net/10204/7618 ER - en_ZA


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