Most studies have only utilized a single dataset to
establish LAI–NDVI relationships and have not taken the
seasonal and year-to-year dynamics into account. This
partly is due to the difficulty in obtaining the LAI changes
on the ground over a period of many years.Spanner et al.
(1990) examined the seasonality of NDVI with LAI fitted
by sine waves and indicated that the seasonal differences in
Advanced Very High Resolution Radiometer (AVHRR)
NDVI were related to phenological changes in LAI, the
fraction of surface cover types contributing to the overall
reflectance, and also the large variations in the solar zenith
angle. This suggests that the NDVI and LAI relationship
may vary throughout the year.