Design and Performance of a Dynamic Gas Flux Chamber

Reichman, Rivka; Rolston, Dennis E.

doi:10.2134/jeq2002.1774

Cited by 26 publications

(21 citation statements)

References 26 publications

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“…Air temperatures measured inside and outside the FC showed a slight damping effect within the chamber. However, the largest absolute temperature difference was always less than 2jC, which is consistent with the findings of Reichman and Rolston (2002) who found a daily average temperature perturbation of 1.5jC due to the chamber. The total mass loss of chloropicrin determined using the FC method was 32.2 kg, or 18.0% of the applied chloropicrin.…”

Section: Flux Chamber Methodssupporting

confidence: 90%

“…Dynamic or flow-through FCs are widely used, convenient tools for field measurements of gas fluxes, including soil fumigants, from soils to the atmosphere (Rolston, 1986;Gao et al, 1997;Reichman and Rolston, 2002;Yates, 2006). The method involves placing an open-bottom chamber on the soil surface, introducing an air flow through the chamber from the inlet to the outlet, and measuring the target gas concentrations in the incoming air and the outgoing air (Fig.…”

Section: Flow-through Flux Chamber Methodsmentioning

confidence: 99%

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Measuring Flux of Soil Fumigants Using the Aerodynamic and Dynamic Flux Chamber Methods

Wesenbeeck¹,

Knuteson²,

Barnekow³

et al. 2007

J of Env Quality

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Methods for measuring and estimating flux density of soil fumigants under field conditions are important for the purpose of providing inputs to air dispersion models and for comparing the effects of management practices on emission reduction. The objective of this study was to measure the flux of 1,3-dichloropropene (1,3-D) and chloropicrin at a site in Georgia (GA) using the aerodynamic method and the dynamic flux chamber (FC) method. A secondary objective was to compare the effects of high density polyethylene (HDPE), and virtually impermeable film (VIF) tarps on fumigant flux at a site in Florida (FL). Chloropicrin and 1,3-D were applied by surface drip application of In-Line soil fumigant on vegetable beds covered by low density polyethylene (LDPE), HDPE, or VIF. The surface drip fumigation using In-Line and LDPE tarp employed in this study resulted in volatilization of 26.5% of applied 1,3-D and 11.2% of the applied chloropicrin at the GA site, as determined using the aerodynamic method. Estimates of mass loss obtained from dynamic FCs were 23.6% for 1,3-D and 18.0% for chloropicrin at the GA site. Flux chamber trials at the FL site indicate significant additional reduction in flux density, and cumulative mass loss when VIF tarp is used. This study supports the use of dynamic FCs as a valuable tool for estimating gas flux density from agricultural soils, and evaluating best management practices for reducing fumigant emissions to the atmosphere.

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Section: Flux Chamber Methodssupporting

confidence: 90%

Section: Flow-through Flux Chamber Methodsmentioning

confidence: 99%

Measuring Flux of Soil Fumigants Using the Aerodynamic and Dynamic Flux Chamber Methods

Wesenbeeck¹,

Knuteson²,

Barnekow³

et al. 2007

J of Env Quality

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show abstract

“…For steady-state flow-through flux chambers, pressure differentials between the inside of the chamber and the ambient atmosphere of less than a few tenths of a pascal are recommended to avoid artificially enhanced flux results (Kanemasu et al 1974;Gao and Yates 1998;Rochette and Hutchinson 2005). Reichman and Rolston (2002) obtained accurate data with their chamber at pressure differentials of 0.5-0.8 Pa while noting that soil texture played a significant role in the absolute pressure differential that could be tolerated. The calculated pressure drop (http://www.…”

Section: Flux Magnitudementioning

confidence: 99%

Spatiotemporal changes in CO2 emissions during the second ZERT injection, August–September 2008

et al. 2010

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This study reports the first field test of a multichannel, auto-dilution, steady-state, soil-CO 2 flux monitoring system being developed to help understand the pathways by which fugitive CO 2 from a geologic sequestration site migrates to the surface. The test was conducted from late August through mid-October 2008 at the Zero Emissions Research and Technology project site located in Bozeman, MT. Twenty steady-state and five non-steadystate flux chambers were installed in a 10 9 15 m area, one boundary of which was directly above a shallow (2-m depth) horizontal injection well located 0.5 m below the water table. A total flux of 52 kg CO 2 day -1 was injected into the well for 13 days and the efflux from the soil was monitored by the chambers before, during, and for 33 days after the injection. The results showed a rapid increase in soil efflux once injection started, with maximal values reached within 3-7 days in most chambers. Efflux returned to background levels within a similar time period after injection ceased. A radial efflux pattern was observed to at least 2 m from the injection well, and evidence for movement of the CO 2 plume during the injection, presumably due to groundwater flow, was seen. The steadystate chambers yielded very stable data, but threefold to fivefold higher fluxes than the non-steady-state chambers. The higher fluxes were attributed to vacuum induced in the steady-state chambers by narrow vent tubes. High winds resulted in significant decreases in measured soil CO 2 efflux, presumably by enhancing efflux from soil outside the chambers.

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“…For steady-state flow-through flux chambers, pressure differentials of less than a few tenths of a pascal are recommended to avoid artificially enhanced flux results (Kanemasu et al 1974;Gao and Yates 1998;Rochette and Hutchinson 2005). Reichman and Rolston (2002) obtained accurate data with their chamber at pressure differentials of 0.5-0.8 Pa while noting that soil texture played a significant role in the absolute pressure differential that could be tolerated. The calculated pressure drop (http://www.pressure-drop.com/Online-Calculator/index.html) across the vent tube at the flow rate we used (40 mL min -1 ) is 8 Pa, which suggests that a relatively substantial vacuum was induced in the chamber under our operating conditions.…”

Section: External Factors Affecting Co 2 Concentration Datamentioning

confidence: 99%

Multi-Channel Auto-Dilution System for Remote Continuous Monitoring of High Soil-CO2 Fluxes

Amonette¹,

Barr²

2009

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SummaryGeological sequestration has the potential capacity and longevity to significantly decrease the amount of anthropogenic CO 2 introduced into the atmosphere by combustion of fossil fuels such as coal. Effective sequestration, however, requires the ability to verify the integrity of the reservoir and ensure that potential leakage rates are kept to a minimum. Moreover, understanding the pathways by which CO 2 migrates to the surface is critical to assessing the risks and developing remediation approaches. Field experiments, such as those conducted at the Zero Emissions Research and Technology (ZERT) project test site in Bozeman, Montana, require a flexible CO 2 monitoring system that can accurately and continuously measure soil-surface CO 2 fluxes for multiple sampling points at concentrations ranging from background levels to several tens of percent. To meet this need, researchers at Pacific Northwest National Laboratory (PNNL) are developing a multi-port battery-operated system capable of both spatial and temporal monitoring of CO 2 at concentrations from ambient to at least 150,000 ppmv.The system consists of soil-gas sampling chambers and a sensing unit based on an infrared gas analyzer (IRGA). Headspace gas from the chambers is continuously pumped through a relay-driven manifold that directs gas from individual chambers into the IRGA. A unique feature of the system is its ability, based on feedback from the IRGA, to automatically dilute the sample gas stream with N 2 using a network of gas-flow controllers, thus allowing measurement of CO 2 levels beyond the normal IRGA limit of 3000 ppmv. The entire system is controlled by a programmable datalogger that also stores the output from the IRGA and gas-flow controllers. The system consists of 27 sampling chambers, thus allowing detailed spatial monitoring of a moderately sized test area (~100 m 2 ). Power can be provided either by an AC source or by an off-grid power-generation system consisting of six deep-cycle batteries charged by both wind and photovoltaic power sources. Dilution gas is provided by a liquid N 2 dewar containing the equivalent of 135,000 L of N 2 (g), enough for 4 weeks of continuous operation. The system is remotely controlled and monitored by connecting the datalogger communication port to a cellular-based modem and antenna.On 27 August 2008, a shallow test injection of CO 2 was started at the ZERT site using a horizontal well located about 2 m below the surface and 1 m below the water table. The PNNL team set up a 27-chamber sampling grid directly above and extending northwest of the injection well. Concentrations were monitored continuously in twenty of these steady-state flux chambers during 13 days of injection (308 h) and for 33 days post injection. These concentration data can be converted directly to flux data using a flow-rate specific constant.With the 20-chamber setup, data were collected on a 2.7-h cycle continuously for nearly 7 weeks. We centered the southeastern side of the sampling grid on a known leakage spot, and this ...

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Design and Performance of a Dynamic Gas Flux Chamber

Cited by 26 publications

References 26 publications

Measuring Flux of Soil Fumigants Using the Aerodynamic and Dynamic Flux Chamber Methods

Measuring Flux of Soil Fumigants Using the Aerodynamic and Dynamic Flux Chamber Methods

Spatiotemporal changes in CO2 emissions during the second ZERT injection, August–September 2008

Multi-Channel Auto-Dilution System for Remote Continuous Monitoring of High Soil-CO2 Fluxes

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