Stationary and time-dependent indoor tracer-gas concentration profiles measured by OP-FTIR remote sensing and SBFM-computed tomography

Drescher, Anushka C.; Park, D.Y.; Yost, Michael G.; Gadgil, Ashok; Levine, Steven P.; Nazaroff, William W.

doi:10.1016/s1352-2310(96)00221-x

Cited by 46 publications

(25 citation statements)

References 11 publications

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“…To our knowledge the absolute reconstruction error has not yet been estimated in tomographic applications in atmospheric sciences. Drescher et al (1997) compared reconstructed concentration fields with real point measurements. Todd and Ramachandran (1994) performed numerical experiments judging the reconstruction quality by some quality criteria, but only considering concentration fields constructed as sum of several randomly located Gaussians and ignoring the errors caused by the discretization.…”

Section: Overview Over Inversion Techniquesmentioning

confidence: 99%

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Longpath DOAS tomography on a motorway exhaust gas plume: numerical studies and application to data from the BAB II campaign

et al. 2004

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Abstract. This paper presents a procedure for performing and optimizing inversions for DOAS tomography and its application to measurement data. DOAS tomography is a new technique to determine 2-and 3-dimensional concentration fields of air pollutants or other trace gases by combining differential optical absorption spectroscopy (DOAS) with tomographic inversion techniques. Due to the limited amount of measured data, the resulting concentration fields are sensitive to the inversion process. Therefore detailed error estimations are needed to determine the quality of the reconstruction. In this paper we compare different row acting methods for the inversion, present a procedure for optimizing the parameters of the reconstruction process and propose a way to estimate the error-fields by numerical studies. The procedure was applied to data from the motorway emission campaign BAB II. Two dimensional NO 2 cross sections at right angles to the motorway could be reconstructed qualitatively well at different meteorological situations. Additionally we present error fields for the reconstructions which show the problems and skills of the used measurement setup. Numerical studies on an improved setup for future motorway campaigns show, that DOAS tomography is able to produce high quality concentration maps.

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Section: Overview Over Inversion Techniquesmentioning

confidence: 99%

“…Todd calculated the nearness on the discrete state vector and thus ignored the discretization error. Drescher et al (1997) used a very similar discrete quality criterion called "figure of merit" by setting the normalization factor to N= s real and thus renouncing the compensation of shifting. .…”

Section: Nearnessmentioning

confidence: 99%

Longpath DOAS tomography on a motorway exhaust gas plume: numerical studies and application to data from the BAB II campaign

et al. 2004

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“…17 The computational algorithm uses a two-phase smooth basis function minimization (SBFM) approach to reconstruct a plume. 19,25,26 First, a single SBFM reconstruction procedure is applied to reconstruct a smoothed ground-level and crosswind concentration profile. 19 During this step, a univariate Gaussian function is fitted to the measured PIC using the ground-level values.…”

Section: Vrpm Reconstruction Algorithmmentioning

confidence: 99%

Uncertainties Associated with the Use of Optical Remote Sensing Technique to Estimate Surface Emissions in Landfill Applications

Abichou

Clark

Tan

et al. 2010

Journal of the Air & Waste Management Association

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“…The first generation of reconstruction approach relied on smooth basis function minimization (SBFM), in which a superposition of basis functions (bivariate Gaussian) are assumed to describe the field of concentration in the plane of measurement. 6 The premise was that the HRPM configuration was inferior to conventional computed tomography (CT) configurations in terms of reconstruction accuracy, but the cost benefits of using one ORS monitor and fewer mirrors would justify the application of HRPM method in various scenarios. It was also assumed that the SBFM was the only algorithm that might provide reasonable reconstruction.…”

Section: Introductionmentioning

confidence: 99%

Theoretical Evaluation of a Method for Locating Gaseous Emission Hot Spots

Hashmonay

2008

Journal of the Air & Waste Management Association

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This paper describes and theoretically evaluates a recently developed method that provides a unique methodology for mapping gaseous emissions from non-point pollutant sources. The horizontal radial plume mapping (HRPM) methodology uses an open-path, path-integrated optical remote sensing (PI-ORS) system in a horizontal plane to directly identify emission hot spots. The radial plume mapping methodology has been well developed, evaluated, and demonstrated. In this paper, the theoretical basis of the HRPM method is explained in the context of the method's reliability and robustness to reconstruct spatially resolved plume maps. Calculation of the condition number of the inversion's kernel matrix showed that this method has minimal error magnification (EM) when the beam geometry is optimized. Minimizing the condition number provides a tool for such optimization of the beam geometry because it indicates minimized EM. Using methane concentration data collected from a landfill with a tunable diode laser absorption spectroscopy (TDLAS) system, it is demonstrated that EM is minimal because the averaged plume map of many reconstructed plume maps is very similar to a plume map generated by the averaged concentration data. It is also shown in the analysis of this dataset that the reconstructions of plume maps are unique for the optimized HRPM beam geometry and independent of the actual algorithm applied.

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Stationary and time-dependent indoor tracer-gas concentration profiles measured by OP-FTIR remote sensing and SBFM-computed tomography

Cited by 46 publications

References 11 publications

Longpath DOAS tomography on a motorway exhaust gas plume: numerical studies and application to data from the BAB II campaign

Longpath DOAS tomography on a motorway exhaust gas plume: numerical studies and application to data from the BAB II campaign

Uncertainties Associated with the Use of Optical Remote Sensing Technique to Estimate Surface Emissions in Landfill Applications

Theoretical Evaluation of a Method for Locating Gaseous Emission Hot Spots

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