Retrieval of canopy height using moderate-resolution imaging spectroradiometer (MODIS) data
In this study we use the 500m Moderate Resolution Imaging Spectroradiometer (MODIS) Bidirectional Reﬂectance Distribution Function (BRDF) product to develop multivariate linear regression models that estimate canopy heights over study sites at Howland Forest, Maine, Harvard Forest, Massachusetts and La Selva Forest, Costa Rica using (1) directional escape probabilities that are spectrally independent and (2) the directional spectral reﬂectances used to derive the directional escape probabilities. These measures of canopy architecture are compared with canopy height information retrieved from the airborne Laser Vegetation Imaging Sensor (LVIS). Both the escape probability and the directional reﬂectance approaches achieve good results, with correlation coeﬀicients in the range 0.54–0.82, although escape probability results are usually slightly better. This suggests that MODIS 500m BRDF data can be used to extrapolate canopy heights observed by widely-spaced satellite LIDAR swaths to larger areas, thus providing wide-area coverage of canopy height.