Sky-view factor approximation using GPS receivers

Authors

  • Lee Chapman,

    Corresponding author
    1. Climate and Atmospheric Research Group, School of Geography and Environmental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
    • Climate and Atmospheric Research Group, School of Geography and Environmental Sciences, University of Birmingham, Birmingham, B15 2TT, UK.
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  • John E. Thornes,

    1. Climate and Atmospheric Research Group, School of Geography and Environmental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
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  • Andrew V. Bradley

    1. Climate and Atmospheric Research Group, School of Geography and Environmental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
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Abstract

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.

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