Subcanopy Solar Radiation model: Predicting solar radiation across a heavily vegetated landscape using LiDAR and GIS solar radiation models

After calibrating the r.sun model to a weather station at our study site, we compare SSR model predictions to black thermopile pyranometer field measurements and to hemispherical photographs using Gap Light Analyzer software, a standard method for point estimation of subcanopy radiation. Both SSR and hemispherical models exhibit a similar linear relationship with pyranometer data, and the models predict similar total solar radiation flux across the range of canopy openness. This approach allows prediction of light regimes at watershed scales with resolution that was previously possible only for local point measurements.