Ground level solar radiation prediction model including cloud cover effects

The model Estimated Solar Radiation (ESR) was developed to predict solar radiation on a horizontal surface for any latitude as a function of total opaque cloud cover. ESR was verified by comparing predicted and observed daily totals of solar radiation on a horizontal surface for Salisbury, Maryland (lat. 38.5°N), and Ely, Nevada (lat. 39.2°N), using hourly values of observed total opaque cloud cover for each location obtained from the National Climatic Center, Asheville, North Carolina. Although the model slightly underpredicts on those days when total opaque cloud cover is high (9–10) and overpredicts on those days when total opaque cloud cover is low (0–1), it provides excellent correlation with observed data (R = 0.87 for Salisbury and 0.94 for Ely).