Retrieval of seasonal dynamics of forest understory reflectance in a Northern European boreal forest from MODIS BRDF data

The spatial and temporal patterns of the forest background reflectance are critically important for retrieving the biophysical parameters of the forest canopy (overstory) and for ecosystem modeling. In this short communication paper, we retrieve the reflectance and seasonal changes of the forest background at 500 m resolution with the 8-day MODIS bidirectional reflectance distribution function (BRDF) model parameters product. For the first time, the satellite data derived results are directly validated with in situ measured seasonal reflectance trajectories of boreal forest understory layers. Our results illustrate the importance of taking into account the documented quality and limitations of the MODIS BRDF product.

► Understory spectra seasonal dynamics retrieved with MODIS BRDF product. ► Validation with in situ measurements of boreal forest understory at Hyytiälä, FIN. ► Mapping not possible with mono-angle data — yes with MODIS multi-angle observations. ► Importance to check quality + limitations of the MODIS BRDF product highlighted.