with different letters indicate that the means can be separated at a significance level of 1 % (a = 0.01). The result 
indicates that the CAR1 performs better than other broad band indices in separating the means at LAI differences 
of 0.05. Figure 7 is an illustration of the means and standard deviations of these vegetation indices plotted against 
LAI. This figure summarizes that the CARI reduces effects of nonphotosynthetic materials in the assessment of 
vegetation canopy y4 par more effectively than broad band vegetation indices. 
4. CONCLUSIONS 
These investigations demonstrate the potential utility of narrow reflectance bands for assessing biophysical 
properties of vegetation canopy. The variability of broad band techniques due to background reflectance 
characteristics are significantly reduced by CARI. It should be stressed that these conclusions are based solely 
upon the results obtained with simulated canopy reflectances and that the SAIL model does not consider all the 
natural phenomena in a vegetation canopy such as spectral variability due to woody biomass. Field experiments 
are planned to evaluate, and further enhance the utility of CARI. 
ACKNOWLEDGEMENTS 
This research was supported by the Biospheric Sciences Branch, NASA/Goddard Space Flight Center and the 
Remote Sensing Laboratory, USDA Beltsville Agricultural Research Center. 
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