Interannual
variations in the contemporary atmospheric CO2 growth rate are large
and are closely linked with El Nino/Southern Oscillation [Bacastow,
1976; Keeling et al., 1989]. Inverse
modeling studies using carbon isotopes indicate that much of the CO2
variability originates within terrestrial ecosystems [Battle et
al., 2000]. Here we
investigate controls over terrestrial ecosystem fluxes during the 7 year period
from 1997 – 2003 using satellite data and the Carnegie-Ames-Stanford-Approach
(CASA) biogeochemical model. In our
analysis, we separate annual variations caused by Net Primary Production (NPP),
heterotrophic respiration (Rh), and biomass burning. NPP was estimated using Advanced Very High
Resolution Radiometer (AVHRR) Global Inventory Modeling and Mapping Studies
(GIMMS), [Tucker et
al., 2005] data in combination with interannual varying
solar radiation [Kanamitsu
et al., 2002; Zhang et al., 2004], precipitation [Adler et
al., 2003], and temperature [Hansen et
al., 1999] data.
The precipitation and temperature data were also used to estimate
heterotrophic respiration rates.
Author: G.R. van der Werf, L.Giglio, G.J. Collatz, et al (jim dot collatz at nasa dot gov)
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