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[en] The horizontal monthly average hourly global and diffuse irradiation data of nine South African and three South West African (Namibian) locations have been analyzed using the recently proposed two-parameter β-distribution model. The best-fit values of the monthly parameters α and β and the corresponding errors have been computed and tabulated for all the 12 locations. It is seen that the model fits both the data very well. The model is also found to fit the morning-afternoon asymmetries in the radiation fairly well. Simple equations have been developed separately for the diffuse and the global radiation that can give the values of the two unknown parameters in terms of the day length SO. This work would be useful to assess the horizontal monthly average hourly global as well as the diffuse irradiation values from the respective daily values in the Southern African region and elsewhere. (author). 7 refs, 4 figs, 54 tabs
[en] Complete text of publication follows. Secular change of the Earth's magnetic field is a comparatively regional phenomenon and does not proceed in a regular and constant manner across the Earth. This gives rise to regions where the magnetic field changes exceptionally strongly on different time scales, currently for instance southern Africa where it has been observed in recent years that secular changes can take place on time scales of 1 year and less. As part of a cooperative project between Germany and South Africa, called Inkaba ye Africa, the COMPASS (COmprehensive Magnetic Processes under the African Southern Sub-continent) program aims to study the regional geomagnetic field and in particular its evolutionary behaviour. In addition to a rapid decrease of the geomagnetic field in this region, as evidenced by the 20% decrease observed at Hermanus, the orientation of the geomagnetic field in southern Africa is also changing rapidly. In the north-western part of southern Africa the declination of the magnetic field is propagating eastward (Tsumeb) and in the south-eastern part it propagates westward (Hermanus and Hartebeesthoek). This results in an overall increase of the spatial gradient over the subcontinent with time. This can possibly be linked to the presence of a patch of reversed flux at the Core-Mantle Boundary below southern Africa. During 2005, 2006, 2007 and 2008 joint field survey campaigns were conducted by the Hermanus Magnetic Observatory (HMO) and the Deutsches GeoForschungsZentrum (GFZ) in South Africa, Namibia and Botswana in order to characterize the time variation of different components of the geomagnetic field. Results obtained from these field surveys, together with data from the 3 continuous recording magnetic observatories in southern Africa at Hermanus, Hartebeesthoek and Tsumeb, are used to model the time variation of the geomagnetic field for 2005-2009. Results obtained indicate that a geomagnetic jerk is in progress in southern Africa.
[en] The finalization of the United Nations Framework Convention on Climate Change (UNFCCC) has catalysed a high degree of debate and interest in the future of coal-fired power generation. Fossil fuel combustion is responsible for a significant percentage of pollutants emitted globally, and coal will continue to play a major role in the energy portfolios of many countries. This is particularly true for developing countries. This fact has resulted in a major focus on technologies which improve the efficiency of coal combustion and conversion to electrical energy, as well as technologies which directly of indirectly reduce overall emissions. The issues around clean coal technologies (CCT) and their evolution, development and uptake in both developed and developing countries are complex. This paper addresses these issues in a Southern African context, viewed from the policy perspective of developing countries and presented in a framework of electricity supply and demand considerations in the region. The principal climate change policy elements proposed for South Africa are presented in the context of the current electricity supply and demand situation in the region. These are presented in the context of Eskom's Integrated Electricity Planning (IEP) process including the environmental considerations inherent in decision-making processes. The potential future of the CCT, barriers to their introduction and potential measures to facilitate their accelerated adoption are discussed. (author). 4 refs., 5 tabs., 2 figs