Normalized Difference Indices – ND705 & ND550

The ND705 has a strong linear correlation with FPAR (fraction of Absorbed Photosynthetically Active Radiation) which is an indicator of chlorophyll at the canopy level. ND550 is a good indicator of GAI (Green Area Index). In addition, these indices are sensitive to senescence and are invariant to chlorophyll florescence. 

 

                                                                      

 

The ND705 and ND550 are indicators of chlorophyll-a (which is the primary photosynthetic pigment).