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Congress: 2008
Author(s): BF Alemaw, TR Chaoka
BF Alemaw, TR Chaoka Faculty of Science, University of Botswana, Private Bag 0022, Gaborone, Botswana Tel: +267 355 2539; fax: +267 318 5097 e-mail:

Keyword(s): climate change impact, GCM, downscaling, rainfed agriculture, southern Africa
AbstractAssessment of impact of possible climate change on water resources systems can be achieved through the use of a continuous water balance model which takes into account of short-time hydrological phenomena, and longterm climate simulations of Global Climate Models (GCM) at scales of months or even longer. Climate change and variability is known to have significant impacts on rainfall variability and hence crop yields in rain-fed agricultural systems. In order to study local agricultural productivity and sustainability of rainfed systems in upland catchments, one way is a closer understanding of the short-time rainfall characteristics and the soil moisture availability through soil moisture accounting crop specific (SMACS) model. This paper focuses on the development of such models which also highlights the merits and challenges of a modelling framework of downscaling longterm monthly rainfall and climatic variability induced by climate change simulated by GCMs to daily sequences of data through a stochastic weather generation model. Its application and integration with a daily soil moisture accounting crop specific (SMACS) model is also demonstrated in an agricultural catchment in the headstreams of the Limpopo basin of Southern Africa. A systematic use of the approach is elaborated by considering specific crops and defining sustainability criteria as an indicators of sustainability of rainfed agriculture and its productivity. A set of climate scenarios from the UNFCC recommended modeling environment of MAGICC/ SCENGEN are considered to assess and document the potential impacts of climate change to sustainability of rainfed agriculture of selected crops (maize, sorghum and sunflower) in a selected watershed within the Limpopo river basin of southern Africa.
2011 IWRA - International Water Resources Association - - Admin