Parameter estimation in surface exchange models using nonlinear inversion:how many parameters can we estimate and which measurements are mostuseful?

摘要

Models of mass and energy exchanges between the biosphere and the atmosphere generally contain a nonlinear dependence between fluxes and model parameters, and,thus estimation of these parameters from measurements in a heterogeneous landscape depends on the scale of the observations. The scale-dependence of a typical surface-exchange model (the CSIRO Biospheric Model, CBM) is examined using the diurnal variation of hourly fluxes of CO2, latent heat, sensible heat and soil heat. The fluxes were measured using micrometeorological techniques over six sites in a grazing/pasture system in SE Australia during a period of three weeks in 1995. Nonlinear parameter inversion was used to determine model parameters.