Five years of cloud enhanced surface UV radiation measurements at two sites (in the Northern and Southern Hemispheres)

Sabburg, J. and Calbo, J. (2009) Five years of cloud enhanced surface UV radiation measurements at two sites (in the Northern and Southern Hemispheres). Atmospheric Research, 93 (4). pp. 902-912. ISSN 0169-8095


This is the first paper to report a detailed comparison between ground based measurements of cloud enhanced ultraviolet (UV) radiation at sites located in both hemispheres. The measurements were undertaken at a Northern Hemisphere site (at the campus of the University of Girona in Spain) and a Southern Hemisphere site (campus of the University of Southern Queensland, Toowoomba, Australia). These sites were chosen as they have both simultaneous sky camera and solar radiation (including UV) measurement campaigns operating for at least 5 years over the same time period. Although hemispheric comparisons of UV radiation are not new, this paper focuses on a study of enhancements, including a comparison of the frequency of occurrence and associated cloud types, at the locations with differing climatology. It is found that although there are commonalities between the sites, such as the correlation of the frequency of enhancements with larger solar zenith angle (SZA) both at Girona and Toowoomba, there are differences too, e.g. the frequency of occurrence of the
enhancements, and the type of clouds that produce most enhancements (cirrus at Girona, cumulus at Toowoomba). It is suggested that this is due to the differences in latitude coupled with a large amount of Cirriform cloud, especially corresponding to large SZA, at Girona. Possible explanations for this major difference were examined, with the most likely hypothesis relating to multiple scattering due to Cirriform cloud and the subsequent effect on UV radiation on a horizontal surface at large SZA.

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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Permanent restricted access to published version due to publisher copyright restrictions.
Faculty / Department / School: Historic - Faculty of Sciences - No Department
Date Deposited: 07 Dec 2011 06:37
Last Modified: 17 Oct 2014 02:14
Uncontrolled Keywords: enhanced; clouds; ultraviolet radiation; sky camera
Fields of Research : 02 Physical Sciences > 0201 Astronomical and Space Sciences > 020102 Astronomical and Space Instrumentation
04 Earth Sciences > 0401 Atmospheric Sciences > 040103 Atmospheric Radiation
04 Earth Sciences > 0401 Atmospheric Sciences > 040106 Cloud Physics
Socio-Economic Objective: E Expanding Knowledge > 97 Expanding Knowledge > 970102 Expanding Knowledge in the Physical Sciences
Identification Number or DOI: 10.1016/j.atmosres.2009.05.003

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