BROAD-BAND TURBIDITY PARAMETERS AND SPECTRAL BAND RESOLUTION OF SOLAR RADIATION FOR THE PERIOD 1954-1991, IN ATHENS, GREECE

✍ Scribed by JACOVIDES, C. P.; KARALIS, J. D.

• Publisher: John Wiley and Sons
• Year: 1996
• Tongue: English
• Weight: 878 KB
• Volume: 16
• Category: Article
• ISSN: 0899-8418
• DOI: 10.1002/(sici)1097-0088(199602)16:2<229::aid-joc6>3.0.co;2-o

✦ Synopsis

In the present analysis broad-band turbidity parameters, which depend upon the attenuation over the entire solar spectrum and which can be determined from unfiltered pyrheliometric measurements of direct beam solar irradiance, are presented.

Unsworth-Monteith attenuation coefficient Tm, Linke factor TL and h g s t r o m turbidity coefficient fl (in parameterized form), were calculated from mid-day observations at the National Observatory of Athens, Greece for the period 1954-1991. Values of hgstrom turbidity coefficient fl compare well w i t h those obtained directly through the so-called pyrheliometric formula Po.

Summertime turbidity levels were found to be higher than winter values.

The long-term variation of the turbidity parameters in conjunction with their frequency distribution depicts the deterioration of air quality in the Athens basin during the period under study. The dependence on the aerosol amount of the fraction of the various spectral bands to direct total irradiance as well as the ratio of diffuse to total global irradiation, are also discussed.