The spectral distribution of solar ultraviolet radiation at the ground

Thesis/Dissertation · Tue Dec 31 23:00:00 EST 1991

OSTI ID:5536671

Albar, O F

Measurements of spectral UV irradiance were made at Sutton Bonington and other sites in Saudi Arabia using a spectroradiometric system developed in this study. On clear days a linear relation between the logarithm of global irradiance I[sub [lambda]] and the air mass m was observed; at short wavelengths, where absorption by ozone is dominant, the slope was related to amount of ozone. The slope was close to that predicted from published ozone absorption coefficients, but at longer wavelengths other attenuation processes also operated. The measurements also suggested that an increase of tropospheric ozone decreases UV irradiance at the earth's surface. Measurements of diffuse UV irradiance showed the significance of the diffuse part of global irradiance in the UV region; the ratio of diffuse to global irradiances depends on wavelength, turbidity, and solar zenith angle. Global irradiance calculated from several mathematical models was compared with measurements; comparison showed that differences may be attributed to the methods of calculating the diffuse irradiance. In conjunction with theoretical calculations using an improved Mie algorithm, measurements of direct solar irradiance revealed information about aerosol size distribution. Analysis of measurements at Sutton Bonington showed that the average aerosol size distribution over the British Midland in summary may be represented by a Junge distribution with [nu] = 3, but anomalies occurred when weather systems carried larger particles. Calculation of ozone amount from direct UV irradiance was shown to be reliable and could be used for monitoring changes in ozone. Measurements of spectral circumsolar irradiance were made at Sutton Bonington and other sites in Saudi Arabia; it was found that the intensity of circumsolar spectral irradiance increases with increasing turbidity and solar zenith angle.

• Research Organization: Nottingham Univ. (United Kingdom)
• OSTI ID: 5536671
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
140100* -- Solar Energy-- Resources & Availability
54 ENVIRONMENTAL SCIENCES
540110
DIFFUSE SOLAR RADIATION
DIRECT SOLAR RADIATION
DISTRIBUTION
ELECTROMAGNETIC RADIATION
ENVIRONMENTAL EFFECTS
GROUND LEVEL
LEVELS
MATHEMATICAL MODELS
OZONE
RADIATIONS
SOLAR FLUX
SOLAR RADIATION
STELLAR RADIATION
ULTRAVIOLET RADIATION