Fig. 1. Chamber headspace CO₂ concentration increase (C_t – C₀) as a function of deployment time (t) and effective chamber height (h) on soil with air-filled porosity = 0.3. Closed circles represent simulated concentrations computed using the numeric diffusion model. Solid lines represent the results of least-squares fits to the simulated concentration data using the non-steady-state diffusive flux estimator, NDFE.