Estimating Solar Radiation in the Regions of Uzbekistan by the Data of Limited Actinometric Observations Taking Cloudiness into Account

Based on the analysis of the cloudiness effect on the insolation of flat solar power units (FSU) of various types, the refined values of the correlation coefficients between direct solar radiation and cloudiness for each natural-climatic region of Uzbekistan were calculated. It was shown that the amount of solar radiation calculated for a specified weather station (WS) by the cloudiness data depended on the choice of a reference actinometric station (AS). For 32 weather stations considered, the average monthly and annual amounts of direct and total solar radiations incident on the FSUs oriented normal to solar beams and at average monthly optimal angles were calculated.