The variability of the daily solar radiation components over Helwan

Measurements of different components of solar radiation were carried out in Helwan, Cairo, Egypt. Helwan (Lat. 29 degrees 52' N, Long. 31 degrees 20' E) is considered the largest polluted region in the world and, the sources of pollution are cement, engineering, iron and steel factories. The data measurements are carried out from sunrise (SR) to sunset (SS) through 4 yr. The daily variation for different components of solar radiation bands as global, direct (Total, Yellow, Red and Infra Red) and diffuse solar radiation are studied and discussed. A computer program was designed to distribute the daily values of different components of solar radiation into energetic bands regions. The width of each band is 625 W/m(2). The energetic band takes the serial numbers from 1 to 16. (C) 2001 Published by Elsevier Science Ltd.