Scanning and mobile multi-axis DOAS measurements of SO2 and NO2 emissions from an electric power plant in Montevideo, Uruguay

Frins, Erna M.; Bobrowski, Nicole; Osorio, Matías; Casaballe, Nicolás; Belsterli, G.; Wagner, Thomas; Platt, U.

doi:10.1016/j.atmosenv.2014.03.069

Cited by 20 publications

(8 citation statements)

References 36 publications

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“…A modified geometrical approach (MGA) for estimating long-path averaged mixing ratios of trace gases (e.g., NO 2 ) from MAX-DOAS measurements at high-altitude sites was proposed in a recent study by Gomez et al (2014). The method assumes a single-scattering geometry and a scattering point altitude close to that of the instrument.…”

Section: Computation Of Path-averaged No 2 Mixing Ratiosmentioning

confidence: 99%

“…More recently, DOAS-type measurements of NO 2 are also performed from a car, which enables the observation of the horizontal variation in tropospheric NO 2 , in addition to its temporal evolution. Such observations have been used for the quantification of total emissions from cities and/or known emission sources (Johansson et al, 2008;Rivera et al, 2009;Ibrahim et al, 2010;Shaiganfar et al, 2011;Wang et al, 2012;Frins et al, 2014;Ionov et al, 2015), for the estimation of emission fluxes from cities (Johansson et al, 2009;Rivera et al, 2013), for the comparison with satellite observations of NO 2 (Wagner et al, 2010;Constantin et al, 2013;Wu et al, 2013), for the comparison with model simulations (Dragomir et al, 2015), and for the validation of airborne measurements of NO 2 (Meier et al, 2017;Tack et al, 2017;Merlaud et al, 2018). While some of the mentioned studies use the MAX-DOAS measurement principle, others apply their instruments in the zenith-sky viewing mode only.…”

Section: Introductionmentioning

confidence: 99%

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Near-surface and path-averaged mixing ratios of NO<sub>2</sub> derived from car DOAS zenith-sky and tower DOAS off-axis measurements in Vienna: a case study

2019

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Abstract. Nitrogen dioxide (NO2), produced as a result of fossil fuel combustion, biomass burning, lightning, and soil emissions, is a key urban and rural tropospheric pollutant. In this case study, ground-based remote sensing has been coupled with the in situ network in Vienna, Austria, to investigate NO2 distributions in the planetary boundary layer. Near-surface and path-averaged NO2 mixing ratios within the metropolitan area of Vienna are estimated from car DOAS (differential optical absorption spectroscopy) zenith-sky and tower DOAS horizon observations. The latter configuration is innovative in the sense that it obtains horizontal measurements at more than a hundred different azimuthal angles – within a 360∘ rotation taking less than half an hour. Spectral measurements were made with a DOAS instrument on nine days in April, September, October, and November 2015 in the zenith-sky mode and on five days in April and May 2016 in the off-axis mode. The analysis of tropospheric NO2 columns from the car measurements and O4 normalized NO2 path averages from the tower observations provide interesting insights into the spatial and temporal NO2 distribution over Vienna. Integrated column amounts of NO2 from both DOAS-type measurements are converted into mixing ratios by different methods. The estimation of near-surface NO2 mixing ratios from car DOAS tropospheric NO2 vertical columns is based on a linear regression analysis including mixing height and other meteorological parameters that affect the dilution and reactivity in the planetary boundary layer – a new approach for such conversion. Path-averaged NO2 mixing ratios are calculated from tower DOAS NO2 slant column densities by taking into account topography and geometry. Overall, lap averages of near-surface NO2 mixing ratios obtained from car DOAS zenith-sky measurements, around a circuit in Vienna, are in the range of 3.8 to 26.1 ppb and in good agreement with values obtained from in situ NO2 measurements for days with wind from the southeast. Path-averaged NO2 mixing ratios at 160 m above the ground as derived from the tower DOAS measurements are between 2.5 and 9 ppb on two selected days with different wind conditions and pollution levels and show similar spatial distribution as seen in the car DOAS zenith-sky observations. We conclude that the application of the two methods to obtain near-surface and path-averaged NO2 mixing ratios is promising for this case study.

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Section: Computation Of Path-averaged No 2 Mixing Ratiosmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Near-surface and path-averaged mixing ratios of NO<sub>2</sub> derived from car DOAS zenith-sky and tower DOAS off-axis measurements in Vienna: a case study

2019

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“…In this case, no correction to the retrieved slant column densities will be needed. For example, if atmospheric visibility is on the order of 30 km or superior and aerosol optical depth less than 0.1 for the plume (see Frins et al, , for instance), the impact of this effect is found to be negligible when the detectors are close to the plume (e.g., distances less than ~0.5 km).…”

Section: Resultsmentioning

confidence: 99%

Comparison Between Regularized Optimization Algorithms for Tomographic Reconstruction of Plume Cross Sections in the Atmosphere

Casaballe

Osorio

Martino

et al. 2017

Earth and Space Science

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We analyze and compare two approaches for the tomographic reconstruction of trace gas distributions in the atmosphere, adapted to differential optical absorption spectroscopy (DOAS) applications. The first approach performs the inversion by solving a regularized least squares problem. Regularization is required because the retrieval of the distribution from a limited set of measurements is an ill‐posed problem. This approach does not consider the nonnegativity of the trace gas concentrations. The second approach is a new proposal that solves an optimization problem with the Laplacian of the solution as the regularization term. This approach enables the possibility of adding the nonnegativity constraint to the solution. The algorithm here is stated as an instance of a convex optimization problem and can numerically be solved using, for example, the CVX package. We test both approaches on reconstructions of simulated gas distributions and different experimental configurations applicable to Multi‐Axis DOAS and multispectral imaging measurements. From the results, we can then determine a set of reconstruction parameters appropriate to real plume measurements.

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“…Almost all techniques used today integrate, out of necessity, over line-of-sight. These include both scanning Differential Optical Absorption Spectroscopy (DOAS) [23] and imaging techniques [24], [14]. This has two important ramifications if concentrations, rather than emission are to be retrieved: (1) an estimate of the third dimension is required, which often introduces significant error and (2) only an average concentration along the line of sight can be derived.…”

Section: Related Workmentioning

confidence: 99%

Measurement of three dimensional volcanic plume properties using multiple ground based infrared cameras

Wood

Thomas

Watson

et al. 2019

ISPRS Journal of Photogrammetry and Remote Sensing

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This study presents a method and a proof of principle system for the direct measurement of volcanic plume 3-D spatial properties. The shape of a plume is reconstructed in three dimensions using multi-view imagery collected from static ground-based cameras. The method was developed using data collected during an expedition to Volcán de Fuego in Guatemala, where four thermal infrared cameras were deployed to capture simultaneous images of the regular ash-rich eruptions. A space carving method was applied to the problem to estimate the volume of the plume at any moment in time. By successively applying the method to sequential sets of images, other quantitative measurements such as the drift direction, ascent rate, and dispersion rate can be deduced. The complete method work-flow is presented including data capture, calibration processes, image processing, the space-carving method, and practical implementation issues. The method is sensitive to the camera alignment, hence a novel technique for estimating the camera orientation angles, making use if a high-accuracy terrain model, is described. Other sources of error relating to the number, synchronisation and resolution of the cameras are also discussed. Preliminary results are presented using data collected at Volcán de Fuego in November 2017 over a period of 1.25 h including three distinct eruptions.

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Scanning and mobile multi-axis DOAS measurements of SO2 and NO2 emissions from an electric power plant in Montevideo, Uruguay

Cited by 20 publications

References 36 publications

Near-surface and path-averaged mixing ratios of NO<sub>2</sub> derived from car DOAS zenith-sky and tower DOAS off-axis measurements in Vienna: a case study

Near-surface and path-averaged mixing ratios of NO<sub>2</sub> derived from car DOAS zenith-sky and tower DOAS off-axis measurements in Vienna: a case study

Comparison Between Regularized Optimization Algorithms for Tomographic Reconstruction of Plume Cross Sections in the Atmosphere

Measurement of three dimensional volcanic plume properties using multiple ground based infrared cameras

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Scanning and mobile multi-axis DOAS measurements of SO2 and NO2 emissions from an electric power plant in Montevideo, Uruguay

Cited by 20 publications

References 36 publications

Near-surface and path-averaged mixing ratios of NO&lt;sub&gt;2&lt;/sub&gt; derived from car DOAS zenith-sky and tower DOAS off-axis measurements in Vienna: a case study

Near-surface and path-averaged mixing ratios of NO&lt;sub&gt;2&lt;/sub&gt; derived from car DOAS zenith-sky and tower DOAS off-axis measurements in Vienna: a case study

Comparison Between Regularized Optimization Algorithms for Tomographic Reconstruction of Plume Cross Sections in the Atmosphere

Measurement of three dimensional volcanic plume properties using multiple ground based infrared cameras

Contact Info

Product

Resources

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Near-surface and path-averaged mixing ratios of NO<sub>2</sub> derived from car DOAS zenith-sky and tower DOAS off-axis measurements in Vienna: a case study

Near-surface and path-averaged mixing ratios of NO<sub>2</sub> derived from car DOAS zenith-sky and tower DOAS off-axis measurements in Vienna: a case study