The Direct Influence of Aerosols on UV Irradiance and the Development of a Synthetic Current UV Index

Turbidity;Atmospheric radiation;UV radiation;Aerosols

Estupin, Jeral Garcia ; Earth and Atmospheric Sciences

University:Georgia Institute of Technology

Department:Earth and Atmospheric Sciences

关键词: Turbidity;    Atmospheric radiation;    UV radiation;    Aerosols;   

Others  :  https://smartech.gatech.edu/bitstream/1853/11602/1/estupinan_jeral_g_200608_phd.pdf

美国|英语

来源: SMARTech Repository

【 摘 要 】

The extinction of solar radiation by atmospheric aerosols influences the Ultraviolet (UV) flux at the surface, which in turn has implications on both human and environmental health. In this study we present measurements of aerosol optical depth ( and #964;a) in the UV at Boulder, Colorado and Atlanta, Georgia using direct measurements of solar UV radiation. The wavelength dependence ofand #964;a and the single scattering albedo ( and #969;o) are determined from the measured values ofand #964;a. Daily averages ofand #964;a range between 0.09 and 0.52 at Boulder and between 0.23 and 2.09 for Atlanta between the wavelengths of 332 and 340 nm. The average ngstrm exponent ( and #945;) is 0.83 at Boulder and 1.43 in Atlanta. Results clearly show that aerosols have a significant effect on the UV Index. Day-to-day changes in the UV index during the one month measurement period in Atlanta range between 2-3 UV Index units at solar noon. It is estimated that when changes inand #964;a andand #969;o occur simultaneously, the UV Index can change up to 6 units from one day to the next at solar noon in the Atlanta area. The single scattering albedo ( and #969;o) was estimated to range between 0.8 and 0.99 for Atlanta. The results suggest an increasing trend inand #969;o with increases inand #964;a. In addition, a new synthetic current UV Index is developed which expands to nearly 10,000 cities the number of current UV Index reports that can be distributed to the public in the United States. Right now, current UV Index values are limited to specific UV measuring sites, constrained by the difficulties of maintaining accurate calibration within the network of UV instruments. The distribution of UV Index values to more cities will increase the publics awareness of the harmful effects of the sun. This new UV Index can be accessed through The Weather Channel website.