We build upon a previous
approach to predict C3 and C4 fractions on the land
surface using new higher resolution satellite datasets on vegetation growth
form and crop type coverage. The approach relies upon the near-universal
restriction of C4 photosynthesis to the herbaceous growth form and
the differing performance of C3 and C4 plants in various
temperature and radiation regimes. MODIS-derived data provide detailed
information on growth form composition (%herbaceous, %woody, and %bare for each
grid cell). Precipitation and temperature variations are derived from station
data climatologies. Combining these data with MODIS-derived NPP fields from
2001, we predict latitudinal variations in C3 and C4 photosynthesis
for South America. These variations will be discussed in the context of the
global carbon cycle and the difficulty they pose for interannual inversion
studies using global CO2 and d13C atmospheric data.
Author: C.J. Still1,2, and R. Powell (still at icess dot ucsb dot edu)
Filesize: 438.58 Kb