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Fluid Dynamics Modelling of the Impact of Climate Change on Solar Radiation in Nigeria

Ohunakin, O.S. (2014) Fluid Dynamics Modelling of the Impact of Climate Change on Solar Radiation in Nigeria. PhD thesis, Covenant University.

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Solar energy applications being developed to assist in limiting the extent of climate change through low-carbon technologies, rely on the natural environment that may be sensitive to changes in the climate, resulting from rising carbon emissions. Climate models are essential to predict the future of solar irradiance fields needed for long range planning of solar energy use. Despite the wide use of numerial models on precipitation and agriculture, their applications on measuring the effect of changing climate on renewable energy resources and weather parameters that contribute to building comforts are very sparse. In this study, the nature of seasonal and interannual variability of solar radiation is investigated alongside global solar radiation climatologies. The International Centre for Theoretical Physics regional climate model (ICTP-RegCM3) driven by European Centre/Hamburg 5 general circulation model (ECHAM5-GCM) and based majorly on the fundamental principles of Newton’s second law, the conservation of mass, the equation of state and the first law of thermodynamics was generated for Nigeria under an enhanced atmospheric CO2 level for the period 1981 to 2100. The model was validated using 11-year solar radiation and mean atmospheric temperature data from two observatories (Nigerian Meteorological Agency (NIMET) and the National Aeronautic and Space Administration (NASA)). Data were analysed using descriptive statistics and Fisher test (p<0.01). The model performed reasonably well when compared with the observed data. The best simulations for seasonal cycle of global solar radiation was obtained over the North having σ' = 1.45, R = 0.84 and σ' = 0.97, R = 0.98 whereas the worst simulations occur over the South with σ' = 0.93, R = 0.62 and σ' = 0.85 and R = 0.87 for the NIMET and NASA respectively. RegCM3 was also found to indicate a fair prediction of the interannual variability of solar radiation and mean air temperature over the climatic zones. Correlations for the solar radiation range from (NIMET) and (NASA) reflecting that the simulated interannual variability over the South and North climatic zones fairly agree with the observed, but more consistent with that observed in the Middle-belt zone . The simulated seasonal global solar radiation bias for the RegCM3 with NIMET and NASA observed datasets in the control period (1981–2010) are of similar magnitudes and showed a mixture of persistent positive and negative biases ranging between –10 and 30%. The seasonal potential future changes in period 1 (2011–2040), showed a reduction in the range of 0 (North) to 3.27% (South) whereas more reduction in global solar radiation is observed in period 2 (2041–2070), having general decrease ranging from 0.11 (Middlebelt) to 3.39% (South). Potential changes in period 3 (2071–2100), is generally characterized with mixed increase and decrease in global solar radiation across the country than the previous two periods. The model has predicted well, the potential effect of changing climate on solar radiation over Nigeria. It was also observed that the finer the resolution in grid spacing, the better the model in representing the observed data.

Item Type: Thesis (PhD)
Subjects: T Technology > TJ Mechanical engineering and machinery
Divisions: Faculty of Engineering, Science and Mathematics > School of Engineering Sciences
Depositing User: Mr Solomon Bayoko
Date Deposited: 03 Feb 2015 13:20
Last Modified: 03 Feb 2015 13:20

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