Several field studies have shown NDVI more strongly and linearly related with
the fraction of absorbed PAR, f APAR , over a range of land cover types (Huemmrich
et al. 2005). Fensholt et al. (2004) found a strong linear relationship between
in situ f APAR and NDVI across three different vegetation types, suggesting that
covariance between f APAR and NDVI is insensitive to variations in leaf angle
distribution (LAD) and vegetation heterogeneity. However, the type of soil
background and PAR absorption by non-photosynthetic vegetation (NPV) can alter
Fig. 1.10 Relationships of tower-derived flux measurements of gross primary productivity
(GPP) and MODIS EVI for (a) annual averages for a range of North America temperate
ecosystems (forest, savanna, grassland), and (b) monthly averages for tropical forests in SE Asia
(dry and humid tropical broadleaf forests) and the Amazon (humid tropical evergreen broadleaf
forest). Adapted from (a) Sims et al. (2006), Copyright (2006), Reprinted with permission from
John Wiley and Sons and (b) Huete et al. (2008), Copyright (2008), Reprinted with permission
from Elsevier
18
A. Huete et al.
the fraction of absorbed PAR, f APAR , over a range of land cover types (Huemmrich
et al. 2005). Fensholt et al. (2004) found a strong linear relationship between
in situ f APAR and NDVI across three different vegetation types, suggesting that
covariance between f APAR and NDVI is insensitive to variations in leaf angle
distribution (LAD) and vegetation heterogeneity. However, the type of soil
background and PAR absorption by non-photosynthetic vegetation (NPV) can alter
Fig. 1.10 Relationships of tower-derived flux measurements of gross primary productivity
(GPP) and MODIS EVI for (a) annual averages for a range of North America temperate
ecosystems (forest, savanna, grassland), and (b) monthly averages for tropical forests in SE Asia
(dry and humid tropical broadleaf forests) and the Amazon (humid tropical evergreen broadleaf
forest). Adapted from (a) Sims et al. (2006), Copyright (2006), Reprinted with permission from
John Wiley and Sons and (b) Huete et al. (2008), Copyright (2008), Reprinted with permission
from Elsevier
18
A. Huete et al.