HR: 0800h
AN: B21B-1030    [Abstracts]
TI: Simulations of site-level ecosystem responses to SRES climate scenarios using a DGVM
AU: * Price, D T
EM: dprice@nrcan.gc.ca
AF: Natural Resources Canada, Northern Forestry Centre 5320 - 122 Street, EDMONTON, AB T6H 3S5 Canada
AU: El Maayar, M
EM: elmaayarm@geog.utoronto.ca
AF: Department of Geography and Program in Planning, University of Toronto 100 St. George St., Room 5047, TORONTO, ON M5S 3G3 Canada
AB: An extensively modified version of the IBIS dynamic global vegetation model was validated at several eddy covariance sites located in Canada and the USA. Each site was considered to be dominated by a single Plant Functional Type (PFT) as parameterised for IBIS. After extensive testing and adjustments, the finalized version of the model was run using site-level climate observations to generate stable soil, litter and vegetation carbon pools for the year 2000. These stabilized pools were then perturbed by running the model for an additional 100 years under each of six GCM climate scenarios (Canadian CGCM2, UK Hadley Centre HadCM3 and Australian CSIRO Mark 2), for each of the IPCC SRES A2 and B2 emissions scenarios. In each simulation, atmospheric CO2 concentration was assumed to increase as projected under the appropriate SRES scenario. Local climate observations were adjusted by combining them with decadal means of the GCM change fields previously interpolated to the site coordinates. The effects of changes in climate alone were also investigated by repeating the runs with atmospheric CO2 concentration fixed at the 2000 level. The general trends in PFT responses to the simulated climate at each site showed significant differences among GCMs, but aside from the greater climatic influences resulting from the warmer A2 scenarios, trends were consistent between the two emissions scenarios. Differences among the trends in key indicators including biomass and litter accumulation, and soil carbon decomposition, reflected regional differences in the scenarios of future climate as projected by each GCM. Changes in net primary productivity production and net ecosystem exchange also varied among the different scenarios but were generally positive. However, much of this positive response could be attributed to the projected changes in CO2 concentration, raising questions about the significance of elevated CO2 concentrations in large-scale simulations of vegetation change.
DE: 0410 Biodiversity
DE: 0414 Biogeochemical cycles, processes, and modeling (0412, 0793, 1615, 4805, 4912)
DE: 0428 Carbon cycling (4806)
DE: 0439 Ecosystems, structure and dynamics (4815)
DE: 0476 Plant ecology (1851)
SC: Biogeosciences [B]
MN: Fall Meeting 2005