A. Bondeau et al., Comparing global models of terrestrial net primary productivity (NPP): importance of vegetation structure on seasonal NPP estimates, GL CHANGE B, 5, 1999, pp. 35-45
Estimates of the seasonal absorbed fraction of photosynthetically active ra
diation (FPAR) and net primary productivity (NPP) are compared among four p
roduction efficiency models (PEMs) and seven terrestrial biosphere models s
imulating canopy development. In addition, the simulated FPARs of the model
s are compared to the FASIR-FPAR derived from NOAA-AVHRR satellite observat
ions. All models reproduce observed summergreen phenology of temperate deci
duous forests rather well, but perform less well for raingreen phenology of
savannas. Some models estimate a much longer active canopy in savannas tha
n indicated by satellite observations. As a result, these models estimate h
igh negative monthly NPP during the dry season. For boreal and tropical eve
rgreen ecosystems, several models overestimate LAI and FPAR. When the simul
ated canopy does respond to unfavourable periods, the seasonal NPP is large
ly determined by absorbed photosynthetically active radiation (APAR). When
the simulated canopy does not respond to unfavourable periods, the light us
e efficiency (LUE) influences the seasonal NPP more. However, the relative
importance of APAR and LUE can change seasonally.