Problems associated with the closed chamber method of soil gas flux measurements.

摘要

The closed chamber method is the most common method used in the estimation of trace gas emissions from soils. I investigated some problems associated with the method in order to improve its efficiency and accuracy.;The first phase of the study involved the development of a diffusion-based model and comparing its performance with the two most common models (linear regression model and Hutchinson and Mosier (H-M) model. Generally, the linear model underestimated fluxes relative to the proposed model and H-M model.;The second phase involved an investigation into the effect of depth of chamber insertion and atmospheric turbulence on the flux estimates. Inserting the chambers deeper was found to increase the headspace concentration build-up.;The third phase studied the effectiveness of the NaOH gas trap used in the static chambers to absorb CO2 as affected by container size. The performance of the gas traps was generally dependent on the fluxes.