HR: 08:30h
AN: A11F-03    [Abstracts]
TI: A Regional Scale Coupled Atmosphere-Ecosystem Model: Formulation and Results
AU: * Medvigy, D
EM: medvigy@fas.harvard.edu
AF: Harvard University, Dept. of Organismic and Evolutionary Biology, HUH, 22 Divinity Avenue, Cambridge, MA 02138 United States
AU: Moorcroft, P R
EM: prm@oeb.harvard.edu
AF: Harvard University, Dept. of Organismic and Evolutionary Biology, HUH, 22 Divinity Avenue, Cambridge, MA 02138 United States
AU: Albani, M
EM: malbani@fas.harvard.edu
AF: Harvard University, Dept. of Organismic and Evolutionary Biology, HUH, 22 Divinity Avenue, Cambridge, MA 02138 United States
AU: Avissar, R
EM: avissar@duke.edu
AF: Duke University, Department of Civil and Environmental Engineering, Edmund T. Pratt Jr. School of Engineering, 123 Hudson Hall, Durham, NC 27708 United States
AU: Walko, R L
EM: robert.walko@duke.edu
AF: Duke University, Department of Civil and Environmental Engineering, Edmund T. Pratt Jr. School of Engineering, 123 Hudson Hall, Durham, NC 27708 United States
AB: The formulation of self-consistent and computationally efficient atmosphere-ecosystem models requires the bridging of a wide range of spatial and temporal scales. Disturbance events such wind-throw, fire and land-use change give rise to significant sub-grid scale heterogeneity in ecosystem structure and function at a variety scales ranging down to the the size of an individual canopy tree, far below the resolution of both climate and numerical weather prediction models. Moreover, over decadal timescales, the spatial distribution of this heterogeneity is dynamic due to the successional dynamics that follow disturbance events within ecosystems. To address this problem, we have developed the Ecosystem Demography Land Surface Model (ED-LSM), an integrated biosphere model that incorporates plant community dynamics, soil carbon and nitrogen biogeochemistry and land surface biophysics. The fast timescale fluxes of carbon, water and energy between the ecosystem and the atmosphere are captured using the leaf photosynthesis and soil decomposition modules of Ecosystem Demography (ED) model coupled to a multi-leaf layer, multi-soil layer implementation of the LEAF-2 biophysical scheme. Long term changes in the biophsyical, ecological and biogeochemical structure of the ecosystem are captured using the ED model's system of size- and age-structured partial differential equations that track the changes in the vertical and horizontal heterogeneity of above and below ground ecosystem structure that result from ecosystem responses to the atmosphere that play out over years, decades and centuries. The model can be run both off-line and coupled to the Regional Atmospheric Modeling System (RAMS), which simulates both atmospheric dynamics and tracer transport of carbon dioxide. We have carried out coupled simulations of the model in temperate, tropical and boreal regions. Comparison of our results with observations from eddy-flux towers and meteorological stations highlights the models ability to capture the influence of the heterogeneous land surface on the dynamics of the land-surface interaction in these different regions on time scales ranging from the synoptic to the decadal.
DE: 3322 Land/atmosphere interactions
DE: 3329 Mesoscale meteorology
DE: 1818 Evapotranspiration
DE: 1851 Plant ecology
DE: 1615 Biogeochemical processes (4805)
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting