β Scribed by Y. Castro-Diez; J. I. Jimenez
No coin nor oath required. For personal study only.
Monthly mean values of daily and hourly global solar irradiation at eight stations in Spain are analysed on the basis of the similarity between the shape of extraterrestrial irradiance during the day and the Gaussian curve. This shape is found to be the same on the Earth's surface after attenuation through the atmosphere whenever the averagedβout period is long enough. Bearing this in mind, it is possible to obtain values for the ratio between the hourly irradiance and the daily global irradiation, from one parameter Ο, with the normal distribution curve. This curve is found to fit closely with experimental results. The mean of the normal distribution is taken at solar noon and the parameter Ο is determined for each month by matching the experimental and the theoretical values at this time. The Οβvalues thus obtained are found to bear an excellent linear correlation with N (monthly mean of maximum sunshine duration). The close correlation of the regression constants with latitude, altitude, and relative bright sunshine duration provides a simple technique for estimating hourly irradiance from the daily values within a certain range of latitudes. This technique makes the estimation of global irradiation for any smaller time interval possible. The errors involved in the estimations obtained are less than 10 per cent in most cases.
π SIMILAR VOLUMES