Quoted from:[1]  Ba Hel V ,  Srinivasan R ,   Ba Khsh H . Solar radiation for Dhahran, Saudi Arabia[J]. Energy, 1986, 11(10):985-989.

https://www.sci-hub.ren/10.1016/0360-5442(86)90029-0

ABSTRACT

An Eppley Normal Incidence Pyrheliometer (NIP) was used to measure the duration of the bright sunshine for Dhahran. These measurements were used to derive a linear correlation between the monthly average daily global solar radiation and the sunshine duration. On an annual basis, the agreement between the predicted and the measured global values is better than 4%. Assessment of the deviations between the measured and the computed global radiation for 11 Saudi Arabian stations are reported. We also found that the Dhahran radiation data fit the theoretical curve of Liu and Jordan, which correlates hourly values and daily totals of the global radiation.

INTRODUCTION

Design of systems utilizing solar energy require knowledge of average solar insolation at the location of interest. Measurements with reliable and calibrated pyranometers are either not available in most parts of the world or have been only recently initiated. This is especially true for the developing countries. To overcome this deficiency, many models have been developed which relate radiation to the various measured meteorological parameters. These formulae are semi-empirical in nature and values of the constants depend upon the location of the station where the measurements are made. The simplest formula in use was suggested by Angstrom’ and correlates the mean daily totals of global radiation with the mean duration of sunshine. Since, the development of this type of correlation requires only a small number of input parameters, we use the Angstrom type regression model. 

The objective of this study is 3-fold. First, to develop an Angstrom type linear relationship between the bright sunshine and the global insolation using direct normal and global measurements for Dhahran. Next, we provide an assessment of the accuracy of the published regression coefficients a and b of a linear Angstrom type equation for 11 other locations since no correlation coefficients were reported. Finally, we examine whether or not the procedure of Liu and Jordan2 can be used to estimate hourly radiation from the daily measured values, using Dhahran data.