Estimation of Clearness Index and its Application in Determining Sky Conditions using Three Cities in Ghana as a Case Study
Ralph Dartey Osei1, Chigbo A. Mgbemene2, Ekechukwu O. Valentine3, Bobie Ansah Samuel4

1Ralph Osei Dartey, Department of Mechanical Engineering, University of Nigeria, Nsukka.
2Bobie Ansah Samuel, Department of Mechanical Engineering, University of Nigeria, Nsukka. 
3Chigbo A. Mgbemene, Professor, Department of Mechanical Engineering, University of Nigeria, Nsukka.
4Ekechukwu Onyemaechi Valentine, Professor, Department of Mechanical Engineering, University of Nigeria, Nsukka. 
Manuscript received on 05 April 2022 | Revised Manuscript received on 25 April 2022 | Manuscript Accepted on 15 May 2022 | Manuscript published on 30 May 2022 | PP: 9-18 | Volume-2 Issue-1, May 2022 | Retrieval Number: 100.1/ijee.C1822051322 | DOI: 10.54105/ijee.C1822.051322
Open Access | Ethics and Policies | Cite | Mendeley | Indexing and Abstracting
© The Authors. Published by Lattice Science Publication (LSP). This is an open access article under the CC-BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)

Abstract: In this work, hourly global radiation and extraterrestrial data for three locations in Ghana, namely Accra, Kumasi, and Navrongo, were used to estimate the daily clearness, monthly mean clearness index, and monthly-averaged hourly clearness index of the study areas. It was observed that the monthly average clearness index of Accra ranged from 0.4505 to 0.6975 and that of Kumasi and Navrongo varied from 0.4553 to 0.6908 and 0.4529 to 0.6949, respectively. There was no overcast sky in the year 2018 for all the three study areas in Ghana, and approximately two-thirds of the year’s day length experienced clear-sky conditions. Partly cloudy conditions were predominant in the wet season of the year. 
Keywords: Clearness Index, Ghana, Sky Conditions
Scope of the Article: Environmental Engineering