Telahun, Yoseph2018-07-102023-11-092018-07-102023-11-091985-10http://10.90.10.223:4000/handle/123456789/7592The thesis submittGd is dividGd into three part81 theoJ:eticalJ computRtional, and experimental" In the first .p. art... R.- eneral theory of attenuation of solRr radiation in the atmosphGl'G due to molecular scatterlng, wat~)~' vapour and aerosol absorpt ion is presented" The theoretical consideration inclUdes integral turbidity factor and its relation to different absorption n}(~Ch'l.llisms. The c3.lcul'J.ted value due to the above absol'ption llIechanismsand the integral turbidity factors for Addis Ababa region, are shown in ChRptel' '1'wo. III the second. part of the thesis different empirical £ol'lllul(1-s relaU,ng gIob:).} solar radiation, geographical and meteoroIogical parameters of a given locality are collected. The most general formula by S'aiyigh et.al. i29 I has been cbosen and applied to Addis Ababa region. With constants given by Sayigh et. al. which 8.1'e claimed to be universal, considerable discrepanejJ~s were obtained. Because of this reason, an ef£O).'t was wl1.de to determillG fl, new set of nine constants of the Sayigl1' s equation whi,ch are applicable to Addis Ababa region.enTheoretical & Experimental AnalysisThesis