T
Timothy C. Johnson
Researcher at Pacific Northwest National Laboratory
Publications - 97
Citations - 1847
Timothy C. Johnson is an academic researcher from Pacific Northwest National Laboratory. The author has contributed to research in topics: Electrical resistivity tomography & Vadose zone. The author has an hindex of 22, co-authored 92 publications receiving 1453 citations. Previous affiliations of Timothy C. Johnson include Boise State University & Idaho National Laboratory.
Papers
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Review: Some low-frequency electrical methods for subsurface characterization and monitoring in hydrogeology
TL;DR: In this paper, the authors used self-potential, resistivity, and induced polarization techniques to measure the electrical response associated with the in-situ generation of electrical current due to the flow of pore water in porous media, a salinity gradient, and the concentration of redox-active species.
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Improved hydrogeophysical characterization and monitoring through parallel modeling and inversion of time-domain resistivity andinduced-polarization data
TL;DR: A parallel distributed-memory forward and inverse modeling algorithm for analyzing resistivity and time-domain induced polar-ization (IP) data and its primary components include distributed computation of the pole solutions in parallel computing environments.
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Advances in interpretation of subsurface processes with time-lapse electrical imaging
TL;DR: In this paper, the authors outline the utility of electrical geophysical methods for time-lapse imaging of hydrological, geochemical, and biogeochemical processes, focusing on new instrumentation, processing, and analysis techniques specific to monitoring.
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Influences of organic carbon speciation on hyporheic corridor biogeochemistry and microbial ecology.
James C. Stegen,Timothy C. Johnson,James K. Fredrickson,Michael J. Wilkins,Allan E. Konopka,William C. Nelson,Evan V. Arntzen,William B. Chrisler,Rosalie K. Chu,Sarah J. Fansler,Emily B. Graham,David W. Kennedy,Charles T. Resch,Malak M. Tfaily,John M. Zachara +14 more
TL;DR: The authors find that previously unrecognized thermodynamic mechanisms regulated by groundwater-river water mixing may strongly influence HC biogeochemical and microbial dynamics.
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Monitoring groundwater‐surface water interaction using time‐series and time‐frequency analysis of transient three‐dimensional electrical resistivity changes
TL;DR: In this paper, the authors used 3D surface time-lapse electrical imaging to monitor subsurface electrical conductivity variations associated with stage-driven groundwater-surface water interactions along a stretch of the Columbia River adjacent to the Hanford 300 near Richland, Washington, USA.