Christopher T Green, Ph.D.
Christopher Green is a Research Hydrologist with the USGS Water Resources Mission Area.
Research Interests
- Flow and reactive transport in complex geological media
- Nitrogen cycling and fluxes in groundwater in agricultural areas
- Flow and solute transport in the unsaturated zone
- Gas transport in the unsaturated zone
- Effects of biofuels crops on groundwater quality
Science and Products
Filter Total Items: 52
Rapid removal of nitrobenzene in a three-phase ozone loaded system with gas-liquid-liquid Rapid removal of nitrobenzene in a three-phase ozone loaded system with gas-liquid-liquid
This study explores the removal rate of nitrobenzene (NB) using a new gas-liquid-liquid (G-L-L) three-phase ozone loaded system consisting of a gaseous ozone, an aqueous solvent phase, and a fluorinated solvent phase (perfluorodecalin, or FDC). The removal rate of NB was quantified in relation to six factors including 1) initial pH, 2) initial NB dosage, 3) gaseous ozone dosage, 4) free...
Authors
Shiyin Li, Jiangpeng Zhu, Guoxiang Wang, Lixiao Ni, Yong Zhang, Christopher T. Green
Field-scale sulfur hexafluoride tracer experiment to understand long distance gas transport in the deep unsaturated zone Field-scale sulfur hexafluoride tracer experiment to understand long distance gas transport in the deep unsaturated zone
A gas-tracer test in a deep arid unsaturated zone demonstrates that standard estimates of effective diffusivity from sediment properties allow a reasonable first-cut assessment of gas contaminant transport. Apparent anomalies in historic transport behavior at this and other waste disposal sites may result from factors other than nonreactive gas transport properties. A natural gradient...
Authors
Michelle Ann Walvoord, Brian J. Andraski, Christopher T. Green, David A. Stonestrom, Robert G. Striegl
Linking aquifer spatial properties and non-Fickian transport in mobile-immobile like alluvial settings Linking aquifer spatial properties and non-Fickian transport in mobile-immobile like alluvial settings
Time-nonlocal transport models can describe non-Fickian diffusion observed in geological media, but the physical meaning of parameters can be ambiguous, and most applications are limited to curve-fitting. This study explores methods for predicting the parameters of a temporally tempered Lévy motion (TTLM) model for transient sub-diffusion in mobile–immobile like alluvial settings...
Authors
Yong Zhang, Christopher T. Green, Boris Baeumer
Decadal surface water quality trends under variable climate, land use, and hydrogeochemical setting in Iowa, USA Decadal surface water quality trends under variable climate, land use, and hydrogeochemical setting in Iowa, USA
Understanding how nitrogen fluxes respond to changes in agriculture and climate is important for improving water quality. In the midwestern United States, expansion of corn cropping for ethanol production led to increasing N application rates in the 2000s during a period of extreme variability of annual precipitation. To examine the effects of these changes, surface water quality was...
Authors
Christopher T. Green, Barbara A. Bekins, Stephen J. Kalkhoff, Robert M. Hirsch, Lixia Liao, Kimberlee K. Barnes
Effect of correlated observation error on parameters, predictions, and uncertainty Effect of correlated observation error on parameters, predictions, and uncertainty
Correlations among observation errors are typically omitted when calculating observation weights for model calibration by inverse methods. We explore the effects of omitting these correlations on estimates of parameters, predictions, and uncertainties. First, we develop a new analytical expression for the difference in parameter variance estimated with and without error correlations for...
Authors
Claire R. Tiedeman, Christopher T. Green
The impact of medium architecture of alluvial settings on non-Fickian transport The impact of medium architecture of alluvial settings on non-Fickian transport
The influence of heterogeneous architecture of alluvial aquifers on non-Fickian transport is explored using the Monte Carlo approach. More than two thousand high-resolution hydrofacies models representing seven groups of alluvial settings are built to test the effects of varying facies proportions, mean length and its anisotropy ratio, juxtapositional tendencies, and sub-facies...
Authors
Yong Zhang, Christopher T. Green, Graham E. Fogg
Science and Products
Filter Total Items: 52
Rapid removal of nitrobenzene in a three-phase ozone loaded system with gas-liquid-liquid Rapid removal of nitrobenzene in a three-phase ozone loaded system with gas-liquid-liquid
This study explores the removal rate of nitrobenzene (NB) using a new gas-liquid-liquid (G-L-L) three-phase ozone loaded system consisting of a gaseous ozone, an aqueous solvent phase, and a fluorinated solvent phase (perfluorodecalin, or FDC). The removal rate of NB was quantified in relation to six factors including 1) initial pH, 2) initial NB dosage, 3) gaseous ozone dosage, 4) free...
Authors
Shiyin Li, Jiangpeng Zhu, Guoxiang Wang, Lixiao Ni, Yong Zhang, Christopher T. Green
Field-scale sulfur hexafluoride tracer experiment to understand long distance gas transport in the deep unsaturated zone Field-scale sulfur hexafluoride tracer experiment to understand long distance gas transport in the deep unsaturated zone
A gas-tracer test in a deep arid unsaturated zone demonstrates that standard estimates of effective diffusivity from sediment properties allow a reasonable first-cut assessment of gas contaminant transport. Apparent anomalies in historic transport behavior at this and other waste disposal sites may result from factors other than nonreactive gas transport properties. A natural gradient...
Authors
Michelle Ann Walvoord, Brian J. Andraski, Christopher T. Green, David A. Stonestrom, Robert G. Striegl
Linking aquifer spatial properties and non-Fickian transport in mobile-immobile like alluvial settings Linking aquifer spatial properties and non-Fickian transport in mobile-immobile like alluvial settings
Time-nonlocal transport models can describe non-Fickian diffusion observed in geological media, but the physical meaning of parameters can be ambiguous, and most applications are limited to curve-fitting. This study explores methods for predicting the parameters of a temporally tempered Lévy motion (TTLM) model for transient sub-diffusion in mobile–immobile like alluvial settings...
Authors
Yong Zhang, Christopher T. Green, Boris Baeumer
Decadal surface water quality trends under variable climate, land use, and hydrogeochemical setting in Iowa, USA Decadal surface water quality trends under variable climate, land use, and hydrogeochemical setting in Iowa, USA
Understanding how nitrogen fluxes respond to changes in agriculture and climate is important for improving water quality. In the midwestern United States, expansion of corn cropping for ethanol production led to increasing N application rates in the 2000s during a period of extreme variability of annual precipitation. To examine the effects of these changes, surface water quality was...
Authors
Christopher T. Green, Barbara A. Bekins, Stephen J. Kalkhoff, Robert M. Hirsch, Lixia Liao, Kimberlee K. Barnes
Effect of correlated observation error on parameters, predictions, and uncertainty Effect of correlated observation error on parameters, predictions, and uncertainty
Correlations among observation errors are typically omitted when calculating observation weights for model calibration by inverse methods. We explore the effects of omitting these correlations on estimates of parameters, predictions, and uncertainties. First, we develop a new analytical expression for the difference in parameter variance estimated with and without error correlations for...
Authors
Claire R. Tiedeman, Christopher T. Green
The impact of medium architecture of alluvial settings on non-Fickian transport The impact of medium architecture of alluvial settings on non-Fickian transport
The influence of heterogeneous architecture of alluvial aquifers on non-Fickian transport is explored using the Monte Carlo approach. More than two thousand high-resolution hydrofacies models representing seven groups of alluvial settings are built to test the effects of varying facies proportions, mean length and its anisotropy ratio, juxtapositional tendencies, and sub-facies...
Authors
Yong Zhang, Christopher T. Green, Graham E. Fogg