Cumulative Frequency Distributions for Hourly Clearness Indices Through Generalized Parameters

The objective of the present investigation is to develop generalized cumulative frequency distributions for hourly clearness indices applicable for different climates. The distributions have been developed in terms of suitable normalized variables relevant on hourly time scale, and include the swing (the difference between the maximum and minimum values of the hourly clearness index for a particular hour over the days in a month) in the hourly clearness index. The adequacy of the distributions developed in predicting the hourly clearness index has been established by comparing with the data values of the 183 secondary locations in addition to the 56 primary locations in USA for which the data are available.