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Modeling of carbon dioxide transport and production in soil: 1. Model development
Author(s) -
Šimůnek Jiří,
Suarez Donald L.
Publication year - 1993
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/92wr02225
Subject(s) - vadose zone , sink (geography) , infiltration (hvac) , groundwater recharge , environmental science , soil science , hydrology (agriculture) , groundwater , soil water , thermodynamics , chemistry , aquifer , geotechnical engineering , geology , physics , cartography , geography
Knowledge of the CO 2 concentration in the unsaturated zone is essential for prediction of solution chemistry in the vadose zone and groundwater recharge as well as for quantifying carbon source/sink terms as part of the global CO 2 mass balance. In this paper we present a predictive simulation model, SOILCO2, based on process‐oriented relationships. The model includes one‐dimensional water flow and multiphase transport of CO 2 utilizing the Richards and the convection‐dispersion equations, respectively, as well as heat flow and a CO 2 production model. The transport of CO 2 in the unsaturated zone can occur in both the liquid and gas phases. The gas transport equation accounts for production of CO 2 and uptake of CO 2 by plant roots associated with root water uptake. The CO 2 production model considers both microbial and root respiration which is dependent on water content, temperature, growth, salinity and plant and soil characteristics. Heat flow is included, since some gas transport parameters, partitioning coefficients and production parameters are strongly temperature dependent. The resulting set of partial differential equations is solved numerically using the finite element and finite difference methods.