Sky‐view factor approximation using GPS receivers

• Published in: International journal of climatology 2002-04, Vol.22 (5), p.615-621
• Main Authors: Chapman, Lee, Thornes, John E., Bradley, Andrew V.
• Format: Article
• Language: English
• Subjects: Earth, ocean, space; Exact sciences and technology; External geophysics; Geophysics. Techniques, methods, instrumentation and models; GPS; longwave radiation; satellite; sky‐view factor; urban heat island
• ISSN: 0899-8418; 1097-0088
• DOI: 10.1002/joc.649

A technique is described which allows the real time measurement of sky‐view factors by proxy. A simple and inexpensive global positioning system (GPS) receiver is used to acquire satellite visibility data, which is then used to develop indices related to the sky‐view factor of a location. The number of visible satellites, dilution of precision and strength of satellite signal are used for analysis and demonstrate that up to 88% of the variation of the variation of the sky‐view factor in urban environments can be explained by a simple index. Explanation is reduced in rural (R2 = 72%) and suburban (R2 = 52%) environments as a consequence of increased image complexity caused by variations in tree cover type and canopy height in addition to just crown closure. The complicity and expensive nature of existing sky‐view factor calculation techniques should mean that utilization of the outlined methodology will improve the accessibility of sky‐view data for future climate studies. Copyright © 2002 Royal Meteorological Society.