HR: 1330h
AN: A52A-0762    [PDF]
TI: Sensitivity of terrestrial ecosystem models of carbon isotope ratios to changes in vegetation properties and meteorology
AU: * Suits, N S
EM: nsuits@atmos.colostate.edu
AF: Colorado State University, Department of Atmospheric Sciences, Fort Collins, CO 80523 United States
AU: Denning, A S
EM: denning@atmos.colostate.edu
AF: Colorado State University, Department of Atmospheric Sciences, Fort Collins, CO 80523 United States
AU: Baker, I T
EM: baker@atmos.colostate.edu
AF: Colorado State University, Department of Atmospheric Sciences, Fort Collins, CO 80523 United States
AU: Thornton, P E
EM: thornton@ucar.edu
AF: The National Center for Atmospheric Research, Climate and Global Dynamics Division, 1850 Table Mesa Dr., Boulder, CO 80305 United States
AU: Miller, J B
EM: John B Miller [John.B.Miller@noaa.gov]
AF: NOAA/CMDL, 325 Broadway, Boulder, CO 80305
AU: Miller, J B
EM: John B Miller [John.B.Miller@noaa.gov]
AF: University of Colorado, Institute for Arctic and Alpine Research, Boulder, CO 80305 United States
AU: Schaefer, K
EM: kevin@atmos.colostate.edu
AF: Colorado State University, Department of Atmospheric Sciences, Fort Collins, CO 80523 United States
AU: Conner Gausepohl, S L
EM: sheri@atmos.colostate.edu
AF: Colorado State University, Department of Atmospheric Sciences, Fort Collins, CO 80523 United States
AU: Gurney, K R
EM: keving@atmos.colostate.edu
AF: Colorado State University, Department of Atmospheric Sciences, Fort Collins, CO 80523 United States
AB: We look at the sensitivity of simulated carbon isotope ratios and CO2 fluxes from several terrestrial ecosystem models to variations in vegetation properties and meteorology. In particular, we compare results from the Community Land Model (CLM2.1); and two versions of the Simple Model of the Biosphere (SiB2.5 and SiB3), to changes in vegetative land cover data sets: Fourier-Adjustment, Solar zenith angle corrected, Interpolated Reconstructed Normalized Difference Vegetation Index (FASIR-NDVI); Global Inventory Monitoring and Modeling Studies NDVI (GIMMS-NDVI); and the CLM Plant Functional Type (PFT) classification scheme, and meteorology: European Center for Medium Range Forecast (ECMWF); National Center for Environmental Prediction (NCEP); and Community Climate Model (NCAR-CCM3). We compare spatial distributions of d13C of terrestrial plant carbon, the zonal gradient of d13C values, and time-series of mean annual d13C values. We also examine the response of the models to changes in meteorology (relative humidity and precipitation) and recycling of canopy CO2. Finally, we compare simulated seasonal cycles of d13C of atmospheric CO2 and the north-south d13C gradient to observed values at several NOAA Flask Stations using response functions (transport fields) developed in Transcom. Results highlight the importance of specified precipitation and precipitation anomalies to carbon isotope discrimination resulting from physiological stress.
DE: 0315 Biosphere/atmosphere interactions
DE: 0400 Biogeosciences
DE: 1040 Isotopic composition/chemistry
DE: 1615 Biogeochemical processes (4805)
SC: Atmospheric Sciences [A]
MN: 2003 Fall Meeting