HR: 16:50h
AN: NG14A-04    [Abstracts]
TI: Maximum Entropy Production and Climate-Vegetation Interactions
AU: * Kleidon, A
EM: akleidon@umd.edu
AF: University of Maryland, Department of Geography and ESSIC 2181 Lefrak Hall, College Park, MD 20742 United States
AB: The climatic conditions near the surface strongly affect the exchange of carbon by terrestrial vegetation, yet vegetation also modulates the physical exchanges of energy and water, thereby affecting climate. Here we investigate the applicability of the principle of Maximum Entropy Production (MEP) to describe the vegetation-climate state emerging from this interaction. We first view the carbon exchange by terrestrial vegetation as a dissipative process that produces entropy by respiring chemical energy, which was produced by photosynthesis, into heat. The application of the principle of Maximum Entropy Production (MEP) to terrestrial vegetation then implies that photosynthetic uptake and subsequent respiration is at its maximum possible rate allowed for by the constraints imposed by the climatological energy- and mass balances. We conduct a range of sensitivity simulations with a climate system model of intermediate complexity in which we modify vegetation-related land surface parameters. The surface energy- and water fluxes from the different sensitivity simulations are then compared to the land surface fluxes of the ECMWF reanalysis data set. This comparison reveals that MEP applied to terrestrial vegetation yields simulated surface energy- and water budgets that are largely consistent with observations. We conclude that MEP is a powerful, general principle that applies not just to purely physical processes, but also to the large-scale dissipative behavior of terrestrial vegetation within the climate system.
DE: 0416 Biogeophysics
DE: 0426 Biosphere/atmosphere interactions (0315)
DE: 0439 Ecosystems, structure and dynamics (4815)
DE: 0495 Water/energy interactions (1878)
DE: 4430 Complex systems
SC: Nonlinear Geophysics [NG]
MN: Fall Meeting 2005