2020/06/30 by Rodney T. Venterea, Søren O. Petersen, Cecile A. M. de Klein +7 · 4 citations
Earth and Planetary Sciences · Environmental Science · #Atmospheric and Environmental Gas Dynamics #Groundwater and Isotope Geochemistry #Groundwater flow and contamination studies
paper · pdf · doi:10.1002/jeq2.20118
openalex publication_date 2020/06/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/03
O) exchange using non-steady-state chambers is converting collected gas concentration versus time data to flux values using a flux calculation (FC) scheme. It is well documented that different FC schemes can produce different flux estimates for a given set of data. Available schemes differ in their theoretical basis, computational requirements, and performance in terms of both accuracy and precision. Nonlinear schemes tend to increase accuracy compared with linear regression but can also decrease precision. The chamber bias correction method can be used if soil physical data are available, but this introduces additional sources of error. Here, the essential theoretical and practical aspects of the most commonly used FC schemes are described as a basis for their selection and use. A gold standard approach for application and selection of FC schemes is presented, as well as alternative approaches based on availability of soil physical property data and intensity of sample collection during each chamber deployment. Additional criteria for scheme selection are provided in the form of an error analysis tool that quantifies performance with respect to both accuracy and precision based on chamber dimensions and sampling duration, soil properties, and analytical measurement precision. Example error analyses are presented for hypothetical conditions illustrating how such analysis can be used to guide FC scheme selection, estimate bias, and inform design of chambers and sampling regimes.