Improved sky imaging for studies of enhanced UV irradiance

Sabburg, J. M. and Long, C. N. (2004) Improved sky imaging for studies of enhanced UV irradiance. Atmospheric Chemistry and Physics, 4 (11-12). pp. 2543-2552. ISSN 1680-7316


A recent World Meteorological Organisation report discussed the importance of continued study of the effect of clouds on the solar UV radiation reaching the earths surface. The report mentions that the use of all-sky imagery offers the potential to understand and quantify cloud effects more accurately. There are an increasing number of studies
investigating the enhancement of surface solar, UV irradiance, and UV actinic flux, using automated CCD and sky
imagers. This paper describes new algorithms applicable to
a commercially available all-sky imager (TSI-440), for research investigating cloud enhanced spectral UV irradiance. Specifically, these include three new algorithms relating to cloud amount at different spatial positions from 1) zenith and 2) from the solar position and 3) the visible brightness of clouds surrounding the sun. A possible relationship between UV enhancement and the occurrence of near-sun cloud brightness is reported based on this preliminary data. It is found that a range of wavelength dependent intensities, from 306 to 400 nm, can occur in one day for UV enhancements. Evidence for a possible decreasing variation of intensity with longer wavelengths is also presented.

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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: © Author(s) 2004. This work is licensed under a Creative Commons Attribution, NonCommerical and ShareAlike Licence.
Faculty / Department / School: Historic - Faculty of Sciences - Department of Biological and Physical Sciences
Date Deposited: 11 Oct 2007 01:11
Last Modified: 02 Jul 2013 22:45
Uncontrolled Keywords: UV enhancement; imager
Fields of Research : 02 Physical Sciences > 0201 Astronomical and Space Sciences > 020102 Astronomical and Space Instrumentation
04 Earth Sciences > 0401 Atmospheric Sciences > 040106 Cloud Physics
04 Earth Sciences > 0401 Atmospheric Sciences > 040103 Atmospheric Radiation
Socio-Economic Objective: E Expanding Knowledge > 97 Expanding Knowledge > 970102 Expanding Knowledge in the Physical Sciences
Identification Number or DOI: SRef-ID: 1680-7324/acp/2004-4-2543

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