Rapid determination of canyon geometry parameters for use in surface radiation budgets

The parameterisation of canyon geometry as a sky-view factor is common practice when studying surface radiation budgets. However, the accurate computation of sky-view factors can prove to be slow and has often resulted in studies involving the sky-view factor to be limited to just a few study sites. A fully automated digital approach to calculating sky-view factors direct from digital imagery is presented along with a simple methodology to determine the impact of surface geometry on the nature of incoming shortwave radiation. The validity of these new automated techniques is tested by a comparative study with alternative methodologies, producing nearly identical results. It is hoped that the rapidity of the techniques should allow for the impacts of canyon geometry on surface radiation budgets to be studied on a scale not previously possible.