AN INTRODUCTION TO Open-Path FT-IR Atmospheric Monitoring

Marshall, Timothy L.; Chaffin, Charles T.; Hammaker, Robert M.; Fateley, William G.

doi:10.1021/es00054a715

Cited by 44 publications

(10 citation statements)

References 7 publications

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“…Nevertheless, three main spectral windows can be identified, which allow OP-FTIR measurements. These windows are located in the wavenumber regions (ν) as follow: (1) 700-1300 cm −1 (passive/active OP-FTIR), (2) 1900-2250 cm −1 , and (3) 2400-3000 cm −1 (window 2 and 3 can only be used for active OP-FTIR; Marshall et al, 1994).…”

Section: Open-path Fourier-transform Infrared (Op-ftir) Spectroscopymentioning

confidence: 99%

Line-averaging measurement methods to estimate the gap in the CO2 balance closure – possibilities, challenges, and uncertainties

2017

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Abstract. An imbalance of surface energy fluxes using the eddy covariance (EC) method is observed in global measurement networks although all necessary corrections and conversions are applied to the raw data. Mainly during nighttime, advection can occur, resulting in a closing gap that consequently should also affect the CO 2 balances. There is the crucial need for representative concentration and wind data to measure advective fluxes. Ground-based remote sensing techniques are an ideal tool as they provide the spatially representative CO 2 concentration together with wind components within the same voxel structure. For this purpose, the presented SQuAd (Spatially resolved Quantification of the Advection influence on the balance closure of greenhouse gases) approach applies an integrated method combination of acoustic and optical remote sensing. The innovative combination of acoustic travel-time tomography (A-TOM) and open-path Fourier-transform infrared spectroscopy (OP-FTIR) will enable an upscaling and enhancement of EC measurements. OP-FTIR instrumentation offers the significant advantage of real-time simultaneous measurements of lineaveraged concentrations for CO 2 and other greenhouse gases (GHGs). A-TOM is a scalable method to remotely resolve 3-D wind and temperature fields. The paper will give an overview about the proposed SQuAd approach and first results of experimental tests at the FLUXNET site Grillenburg in Germany.Preliminary results of the comprehensive experiments reveal a mean nighttime horizontal advection of CO 2 of about 10 µmol m −2 s −1 estimated by the spatially integrating and representative SQuAd method. Additionally, uncertainties in determining CO 2 concentrations using passive OP-FTIR and wind speed applying A-TOM are systematically quantified. The maximum uncertainty for CO 2 concentration was estimated due to environmental parameters, instrumental characteristics, and retrieval procedure with a total amount of approximately 30 % for a single measurement. Instantaneous wind components can be derived with a maximum uncertainty of 0.3 m s −1 depending on sampling, signal analysis, and environmental influences on sound propagation. Averaging over a period of 30 min, the standard error of the mean values can be decreased by a factor of at least 0.5 for OP-FTIR and 0.1 for A-TOM depending on the required spatial resolution. The presented validation of the joint application of the two independent, nonintrusive methods is in the focus of attention concerning their ability to quantify advective fluxes.

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Section: Open-path Fourier-transform Infrared (Op-ftir) Spectroscopymentioning

confidence: 99%

Line-averaging measurement methods to estimate the gap in the CO2 balance closure – possibilities, challenges, and uncertainties

2017

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“…These results were established in French, European and American multicenter studies as well as through the compilation of numerous studies [1]. This is an obvious and sufficient reason for air monitoring to become an essential element in any type of human or industrial activity at the local level [2,3]. Among the various techniques, ground-based infrared (IR) remote-sensing technologies are promising for the large-scale monitoring of atmospheric gas plume detection [4][5][6][7][8].…”

Section: Introductionmentioning

confidence: 95%

Near Real-Time Ground-to-Ground Infrared Remote-Sensing Combination and Inexpensive Visible Camera Observations Applied to Tomographic Stack Emission Measurements

et al. 2018

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Evaluation of the environmental impact of gas plumes from stack emissions at the local level requires precise knowledge of the spatial development of the cloud, its evolution over time, and quantitative analysis of each gaseous component. With extensive developments, remote-sensing ground-based technologies are becoming increasingly relevant to such an application. The difficulty of determining the exact 3-D thickness of the gas plume in real time has meant that the various gas components are mainly expressed using correlation coefficients of gas occurrences and path concentration (ppm.m). This paper focuses on a synchronous and non-expensive multi-angled approach combining three high-resolution visible cameras (GoPro-Hero3) and a scanning infrared (IR) gas system (SIGIS, Bruker). Measurements are performed at a NH 3 emissive industrial site (NOVACARB Society, Laneuveville-devant-Nancy, France). Visible data images were processed by a first geometrical reconstruction gOcad ® protocol to build a 3-D envelope of the gas plume which allows estimation of the plume's thickness corresponding to the 2-D infrared grid measurements. NH 3 concentration data could thereby be expressed in ppm and have been interpolated using a second gOcad ® interpolation algorithm allowing a precise volume visualization of the NH 3 distribution in the flue gas steam.

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“…A closing gap for energy balance measurements which affects the balance closure of greenhouse gases (GHGs), e.g., CO 2 , is still observed at all stations in global measuring networks (Marcolla et al, 2014). This imbalance exists although all necessary corrections and calculations are applied to the flow measurements using the eddy covariance (EC) method (e.g., Foken et al, 2010;Mauder et al, 2006). Obviously, the existing measurement methods do not capture all relevant transport mechanisms, especially during calm and stable nighttime conditions.…”

Section: Introductionmentioning

confidence: 99%

Line-averaging measurement methods to estimate the gap in the CO2 balance closure – possibilities, challenges and uncertainties

Ziemann¹,

Starke²,

Schütze³

2017

Preprint

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Abstract. An imbalance of surface energy fluxes using the eddy covariance (EC) method is observed in global measurement networks although all necessary corrections and conversions are applied to the raw data. Mainly during nighttime, advection can occur resulting in a closing gap that consequently should also affect the CO2 balances. There is the crucial need for representative concentration and wind data to measure advective fluxes. Ground-based remote sensing techniques are an ideal tool as they provide the spatially representative CO2 concentration together with wind components within the same voxel structure. For this purpose, the presented SQuAd (Spatially resolved Quantification of the Advection influence on the balance closure of greenhouse gases)-approach applies an integrated method combination of acoustic and optical remote sensing. The innovative combination of acoustic travel-time tomography (A-TOM) and open-path Fourier transform infrared spectroscopy (OP-FTIR) will enable an upscaling and enhancement of EC measurements. OP-FTIR instrumentation offers the significant advantage of real-time simultaneous measurements of line-averaged concentrations for CO2 and other greenhouse gases (GHGs). A-TOM is a scalable method to remotely resolve 3D wind and temperature fields. The paper will give an overview about the proposed SQuAd-approach and first results of experimental tests at the FLUXNET site Grillenburg in Germany. Preliminary results of the comprehensive experiments reveal a mean nighttime horizontal advection of CO2 of about 10 μmol m−2 s−1 estimated by the spatially integrating and representative SQuAd method. Thereby, uncertainties in determining CO2 concentrations using passive OP-FTIR and wind speed applying A-TOM are systematically quantified. The maximum uncertainty for CO2 concentration was estimated due to environmental parameters, instrumental characteristics, and retrieval procedure with a total amount of approx. 30 % for a single measurement. Instantaneous wind components can be derived with a maximum uncertainty of 0.3 m s−1 depending on sampling, signal analysis, and environmental influences on sound propagation. After the application of averaging over a period of 30 minutes, the standard error of the mean values can be decreased by a factor of at least 0.5 for OP-FTIR and 0.1 for A-TOM depending on the required spatial resolution. The presented validation of the joint application of the two independent, non-intrusive methods is in the focus of attention concerning their ability to quantify advective fluxes.

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AN INTRODUCTION TO Open-Path FT-IR Atmospheric Monitoring

Cited by 44 publications

References 7 publications

Line-averaging measurement methods to estimate the gap in the CO<sub>2</sub> balance closure – possibilities, challenges, and uncertainties

Line-averaging measurement methods to estimate the gap in the CO<sub>2</sub> balance closure – possibilities, challenges, and uncertainties

Near Real-Time Ground-to-Ground Infrared Remote-Sensing Combination and Inexpensive Visible Camera Observations Applied to Tomographic Stack Emission Measurements

Line-averaging measurement methods to estimate the gap in the CO<sub>2</sub> balance closure – possibilities, challenges and uncertainties

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AN INTRODUCTION TO Open-Path FT-IR Atmospheric Monitoring

Cited by 44 publications

References 7 publications

Line-averaging measurement methods to estimate the gap in the CO&lt;sub&gt;2&lt;/sub&gt; balance closure – possibilities, challenges, and uncertainties

Line-averaging measurement methods to estimate the gap in the CO&lt;sub&gt;2&lt;/sub&gt; balance closure – possibilities, challenges, and uncertainties

Near Real-Time Ground-to-Ground Infrared Remote-Sensing Combination and Inexpensive Visible Camera Observations Applied to Tomographic Stack Emission Measurements

Line-averaging measurement methods to estimate the gap in the CO&lt;sub&gt;2&lt;/sub&gt; balance closure – possibilities, challenges and uncertainties

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Line-averaging measurement methods to estimate the gap in the CO<sub>2</sub> balance closure – possibilities, challenges, and uncertainties

Line-averaging measurement methods to estimate the gap in the CO<sub>2</sub> balance closure – possibilities, challenges, and uncertainties

Line-averaging measurement methods to estimate the gap in the CO<sub>2</sub> balance closure – possibilities, challenges and uncertainties