Field Evaluation of a Method for Estimating Gaseous Fluxes from Area Sources Using Open-Path Fourier Transform Infrared

Hashmonay, Ram A.; Natschke, David F.; Wagoner, Keith; Harris, D. Bruce; Thompson, Edgar L.; Yost, Michael G.

doi:10.1021/es0017108

Cited by 45 publications

(26 citation statements)

References 12 publications

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“…Emissions of NH 3 during the Indiana experiment were determined at 30-min intervals from wind profiles based on the three anemometers and concentration profiles based on the multiple TDLAS-measured PIC using the vertical radial plume mapping method (Hashmonay et al, 2001). This method utilizes the product of an interpolated mass concentration distribution and interpolated wind speed normal to the measurement plane and is therefore fundamentally an IHF method.…”

Section: Open-path Integrated Horizontal Flux Methods (Ihf)mentioning

confidence: 99%

Areal-averaged trace gas emission rates from long-range open-path measurements in stable boundary layer conditions

et al. 2012

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Abstract. Measurements of land-surface emission rates of greenhouse and other gases at large spatial scales (10 000 m 2 ) are needed to assess the spatial distribution of emissions. This can be readily done using spatial-integrating micrometeorological methods like flux-gradient methods which were evaluated for determining land-surface emission rates of trace gases under stable boundary layers. Non-intrusive path-integrating measurements are utilized. Successful application of a flux-gradient method requires confidence in the gradients of trace gas concentration and wind, and in the applicability of boundary-layer turbulence theory; consequently the procedures to qualify measurements that can be used to determine the flux is critical. While there is relatively high confidence in flux measurements made under unstable atmospheres with mean winds greater than 1 m s −1 , there is greater uncertainty in flux measurements made under free convective or stable conditions. The study of N 2 O emissions of flat grassland and NH 3 emissions from a cattle lagoon involves quality-assured determinations of fluxes under low wind, stable or night-time atmospheric conditions when the continuous "steady-state" turbulence of the surface boundary layer breaks down and the layer has intermittent turbulence. Results indicate that following the Monin-Obukhov similarity theory (MOST) flux-gradient methods that assume a loglinear profile of the wind speed and concentration gradient incorrectly determine vertical profiles and thus flux in the stable boundary layer. An alternative approach is considered on the basis of turbulent diffusivity, i.e. the measured friction velocity as well as height gradients of horizontal wind speeds and concentrations without MOST correction for stability. It is shown that this is the most accurate of the flux-gradient methods under stable conditions.

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Section: Open-path Integrated Horizontal Flux Methods (Ihf)mentioning

confidence: 99%

Areal-averaged trace gas emission rates from long-range open-path measurements in stable boundary layer conditions

et al. 2012

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“…5 EPA has successfully used the OP-FTIR/VRPM method to quantify mass emission flux from numerous sources in field campaigns and controlled tracer release studies. [10][11][12][13][14][15] For typically encountered wind conditions, the VRPM method achieves emission flux measurement accuracies within 10% of actual. Table 1 contains a summary of controlled tracer release results under typical wind conditions.…”

Section: Methodsmentioning

confidence: 99%

“…The technique can seriously underestimate emission flux under unstable atmospheric conditions. 13 Data quality acceptance criteria based on wind speed and direction have been established to ensure accurate emission flux assessment. 5 …”

Section: Methodsmentioning

confidence: 99%

Open-Path Tunable Diode Laser Absorption Spectroscopy for Acquisition of Fugitive Emission Flux Data

Thoma

Shores

Thompson

et al. 2005

Journal of the Air & Waste Management Association

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Air pollutant emission from unconfined sources is an increasingly important environmental issue. The U.S. Environmental Protection Agency (EPA) has developed a ground-based optical remote-sensing method that enables direct measurement of fugitive emission flux from large area sources. Open-path Fourier transform infrared spectroscopy (OP-FTIR) has been the primary technique for acquisition of pollutant concentration data used in this emission measurement method. For a number of environmentally important compounds, such as ammonia and methane, open-path tunable diode laser absorption spectroscopy (OP-TDLAS) is shown to be a viable alternative to Fourier transform spectroscopy for pollutant concentration measurements. Near-IR diode laser spectroscopy systems offer significant operational and cost advantages over Fourier transform instruments enabling more efficient implementation of the measurement strategy. This article reviews the EPA's fugitive emission measurement method and describes its multipath tunable diode laser instrument. Validation testing of the system is discussed. OP-TDLAS versus OP-FTIR correlation testing results for ammonia (R 2 ϭ 0.980) and methane (R 2 ϭ 0.991) are reported. Two example applications of tunable diode laser-based fugitive emission measurements are presented.

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“…These instruments measure path integrated concentration (PIC), which were used by VRPM to estimate the concentration field across the measurement plane. The VRPM procedure utilizes several downwind PICs at different heights to statistically reconstruct the concentration field [2,3]. The PIC measurements are made from a near-ground concentration sensor to reflectors positioned at different heights on a tower.…”

Section: It Requires Knowledge Of the Tracer Concentration And Wind Fmentioning

confidence: 99%

Measuring Trace Gas Emission from Multi-Distributed Sources Using Vertical Radial Plume Mapping (VRPM) and Backward Lagrangian Stochastic (bLS) Techniques

Ro¹,

Johnson²,

Hunt³

et al. 2011

Atmosphere

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Two micrometeorological techniques for measuring trace gas emission rates from distributed area sources were evaluated using a variety of synthetic area sources. The vertical radial plume mapping (VRPM) and the backward Lagrangian stochastic (bLS) techniques with an open-path optical spectroscopic sensor were evaluated for relative accuracy for multiple emission-source and sensor configurations. The relative accuracy was calculated by dividing the measured emission rate by the actual emission rate; thus, a relative accuracy of 1.0 represents a perfect measure. For a single area emission source, the VRPM technique yielded a somewhat high relative accuracy of 1.38 ± 0.28. The bLS technique resulted in a relative accuracy close to unity, 0.98 ± 0.24. Relative accuracies for dual source emissions for the VRPM and bLS techniques were somewhat similar to single source emissions, 1.23 ± 0.17 and 0.94 ± 0.24, respectively. When the bLS technique was used with vertical point concentrations, the relative accuracy was unacceptably low, <0.62. However, when using multiple point sensors in a horizontal line, the bLS technique yielded a relative accuracy of 1.08 ± 0.44. Altogether, these results suggest that the bLS technique has significant potential for measuring trace gas emissions from distributed agricultural systems.

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Field Evaluation of a Method for Estimating Gaseous Fluxes from Area Sources Using Open-Path Fourier Transform Infrared

Cited by 45 publications

References 12 publications

Areal-averaged trace gas emission rates from long-range open-path measurements in stable boundary layer conditions

Areal-averaged trace gas emission rates from long-range open-path measurements in stable boundary layer conditions

Open-Path Tunable Diode Laser Absorption Spectroscopy for Acquisition of Fugitive Emission Flux Data

Measuring Trace Gas Emission from Multi-Distributed Sources Using Vertical Radial Plume Mapping (VRPM) and Backward Lagrangian Stochastic (bLS) Techniques

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