Linking Lidar, SAR and ED: How lidar and SAR fusion can influence the predictions and modeling of future forest states

Among remote sensing tools available for forest structure research, the active methods of LiDAR and RaDAR possess the potential to provide faster and more valuable information than many other methods available. One of their major downfalls is the survey cost incurred, particularly in scientific research where many instances require dual coverage. Identifying synergies between these methods could potentially reduce the need for forest coverage by both sensors. Here we present a study that addresses these limitations primarily through comparison of interferometric coherence between direct measurements provided by radar interferometry and through those predicted from extinction estimates obtained from LiDAR waveforms. The theories presented here for establishing extinction estimates from radar and LiDAR synergy have the potential to improve forest biomass estimation where interferometric radar data has been acquired. This is because both height and extinction values can potentially be obtained from radar data alone through the establishment of this relationship with the lidar derived extinction and therefore coherence. In addition, the relevance of obtaining large-scale extinction estimates using radar coverage is emphasised within a modelling environment using the Ecological Demography (ED) model. We examine, for multiple sites, how the availability of radar coherence and therefore extinction estimates provided by the theory can be used within the forest modelling process to provide canopy extinction variations which drive photosynthetic processes. In particular, the influence of functional type and location variations are analysed and ultimately the theory's ability to predict the current and future status of forests.