Estimating 3D canopy´s gap fraction using photographic method

Gap fraction, which is the probability that a light penetrates through the canopy unintercepted and reaches the surface under the canopy, is characteristic geometric parameter of canopy´s structure, and has great influence on radiative transfer of the vegetation. In this article, a photographic method was introduced to efficiently and accurately calculate the gap fraction of three-dimensional (3D) canopies. The 3D structures generated by the Clumped Architecture Model of Plants (CLAMP). The key parameters of CLAMP model include sowing scheme, clumping index, average leaf angle and leaf area index. By analyzing the sensitivity of these parameters to gap fraction, the changing features of gap fraction were found. The research of this article shows that photographic method is a powerful way to quantitatively study vegetation by remote sensing technology, and has potential of wider applications.