Application of normal distribution in modeling global irradiation

The utility of the normal distribution curve in modeling hourly global radiation is presented and discussed. It is shown that nonzero hourly insolation values for each day can be represented by the variance of the normal distribution curve and total daily insolation. It is shown that using the normal distribution curve for representing hourly insolation values does not cause a significant loss of information content. The mean of the normal distribution curve is taken at solar noon. The variance of the normal curve is then calculated from the recorded data by matching the recorded value and the value obtained from the normal distribution curve at solar noon. This approach provides a simple and easy method for estimating hourly radiation and eliminates the need for large digital computers. It is shown that 24 hourly insolation values can be represented by four variables, namely, total daily insolation, variance of the normal distribution curve, and the times of sunrise and sunset.<>