We have adjusted the parameters TSAVI, and KTsAvr of equation
(11) using non linear fitting technics:
TSAW=0.900.(1-exp( -0.42O.W)) (12)
the TSAVI, value is in good agreement with model simulation. But the
KTsAVI value is lower than SAIL model results. The difference could
be due to the non homogeneous spatial repartition of leaves in wheat
fields as compared to the random homogeneous repartition assomptions
of the SAIL model. The spatial repartition and also the leaf angle
inclination depends on the phenological stage of the crop and will in
consequence be also linked to the LAI value. This problem could be
solved by applying a more specific model for describing the TSAWLAI
relationship for real particular crops. Nethertheless, we can observe
the very good sensitivity of TSAVI to W and it's low noise level for
low w.
APAR ESTIMATION