Spectral measurements of visible solar direct-normal irradiance and air pollutant attenuation coefficients at Helwan
✍ Scribed by M.A. Mosalam Shaltout; U. Ali Rahoma; A. Fathy
- Publisher
- Elsevier Science
- Year
- 1996
- Tongue
- English
- Weight
- 524 KB
- Volume
- 7
- Category
- Article
- ISSN
- 0960-1481
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✦ Synopsis
Abstrac~Solar radiation spectra were measured by a ground-level pyrheliometer (Eppley NIP) equipped with a filter wheel. Three flat, circular, Schott filters were used to define three spectral bands. The filters were large band-pass filters of the types OG530, RG630 and RG695. The experiment was conducted from June 1991 to May 1992 on the roof of the new building of the National Research Institute of Astronomy and Geophysics (NRIAG) at Helwan. The Linke turbidity factor for the integrated radiation, and the spectral attentuation coefficients of solar energy caused by aerosols were computed. In comparison with earlier measurements in 1910, 1967 and 1987, it is clear that there is a continuous increase in the turbidity factor, due to an increase of industrial waste in the Helwan atmosphere. A correlation analysis between the turbidity factors and the total suspended particles, smoke and sulphur dioxide was carried out. Meteorological elements and sand storms have been taken into consideration in the correlation analysis.