El Nino southern oscillation based rainfall forecasts in southern Africa. II. daily forecasts could help summer planting decisions in Zimbabwe

Cobon, D. H. and Unganai, L. S. and Clewett, J. F. (2003) El Nino southern oscillation based rainfall forecasts in southern Africa. II. daily forecasts could help summer planting decisions in Zimbabwe. In: 7th International Rangelands Congress 2003: Rangelands in the New Millennium, 26 Jul-1 Aug 2003, Durban, South Africa.

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Abstract

Analysis of historical data of daily rainfall for Harare showed that El Nino Southern Oscillation (ENSO) impacts on the timing of break-of-dry season and follow-up rainfall as well as the frequency of rain events during summer (Nov-Mar). The Southern Oscillation Index (SOI) was a useful indicator of the timing and frequency of these events, defined as 40mm of rainfall in 3 days. Median dates for the first and second events were 1 December and 17 December respectively; ENSO contributed to a shift in these dates of about 2 weeks. The percent chance of receiving break-of-season rainfall by 1 December during La Nina years was 67% compared to 30% in El Nino years. Maize is a staple food in Zimbabwe and delaying planting after 1 December can result in lower yields. Communal farmers could benefit from this apparent ENSO signal in Zimbabwe by adjusting crop variety, planting time and fertilizer rate. However, poor spatial coverage of long-term (>80 years) daily rainfall data in Zimbabwe limits widespread application.


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Item Type: Conference or Workshop Item (Commonwealth Reporting Category E) (Paper)
Refereed: Yes
Item Status: Live Archive
Additional Information: This publication is copyright. It may be reproduced in whole or in part for the purposes of study, research, or review, but is subject to the inclusion of an acknowledgment of the source.
Faculty / Department / School: Historic - Faculty of Engineering and Surveying - Department of Agricultural, Civil and Environmental Engineering
Date Deposited: 28 Jan 2015 01:27
Last Modified: 13 May 2015 03:54
Uncontrolled Keywords: El Nino; southern oscillation; break-of-season; Zimbabwe
Fields of Research : 07 Agricultural and Veterinary Sciences > 0701 Agriculture, Land and Farm Management > 070102 Agricultural Land Planning
04 Earth Sciences > 0401 Atmospheric Sciences > 040107 Meteorology
04 Earth Sciences > 0401 Atmospheric Sciences > 040105 Climatology (excl.Climate Change Processes)
Socio-Economic Objective: B Economic Development > 82 Plant Production and Plant Primary Products > 8204 Summer Grains and Oilseeds > 820401 Maize
URI: http://eprints.usq.edu.au/id/eprint/26424

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