Validation of improved sky camera algorithm for measurement of cloud around the Sun

Sabburg, Jeff and Wong, Joe (1999) Validation of improved sky camera algorithm for measurement of cloud around the Sun. In: 2nd Internet Conference on Photochemistry and Photobiology: Protection Against the Hazards of UVR 1999, 18 Jan-5 Feb 1999.

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Abstract

A low cost automatic sky camera system was designed, constructed and tested for the use to study the effect of cloud on the amount of ultraviolet radiation (UV) at the ground level. This paper presents the results of a twelve-month comparison between the results obtained with the sky camera system and those of manual observation, with the major cloud type of Cumulus (36%). The sky camera system is the first to measure cloud properties near the sun, in contrast to whole-sky assessment. images were analysed using an improved image-processing algorithm estimating the cloud amount in an angular region of 37.5  around the sun for local noon at Toowoomba, Australia (27.6 oC). The state of solar disk obstruction was also determined, as it would be useful for assessing the effect of cloud on the UV level. It was found that the new algorithm compared favourably with a previous evaluation of an earlier system (85.2% for disk obstruction and 81.7% for cloud amount). The finding suggests that the camera system is suitable for the use of long-term radiation studies.


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Item Type: Conference or Workshop Item (Commonwealth Reporting Category E) (Paper)
Refereed: Yes
Item Status: Live Archive
Faculty / Department / School: Historic - Faculty of Engineering and Surveying - No Department
Date Deposited: 30 Nov 2007 11:55
Last Modified: 13 Nov 2013 23:42
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: D Environment > 96 Environment > 9602 Atmosphere and Weather > 960203 Weather
URI: http://eprints.usq.edu.au/id/eprint/10693

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