scholarly journals An indirect-calibration method for non-target quantification of trace gases applied to a time series of fourth-generation synthetic halocarbons at the Taunus Observatory (Germany)

2021 ◽  
Vol 14 (6) ◽  
pp. 4669-4687
Author(s):  
Fides Lefrancois ◽  
Markus Jesswein ◽  
Markus Thoma ◽  
Andreas Engel ◽  
Kieran Stanley ◽  
...  
Keyword(s):  
Stratospheric Ozone ◽  
Trace Gases ◽  
Mass Range ◽  
Calibration Method ◽  
In Situ Measurements ◽  
Atmospheric Composition ◽  
Fourth Generation ◽  
Calibration Gas ◽  
Tof Ms

Abstract. Production and use of many synthetic halogenated trace gases are regulated internationally due to their contribution to stratospheric ozone depletion or climate change. In many applications they have been replaced by shorter-lived compounds, which have become measurable in the atmosphere as emissions increased. Non-target monitoring of trace gases rather than targeted measurements of well-known substances is needed to keep up with such changes in the atmospheric composition. We regularly deploy gas chromatography (GC) coupled to time-of-flight mass spectrometry (TOF-MS) for analysis of flask air samples and in situ measurements at the Taunus Observatory, a site in central Germany. TOF-MS acquires data over a continuous mass range that enables a retrospective analysis of the dataset, which can be considered a type of digital air archive. This archive can be used if new substances come into use and their mass spectrometric fingerprint is identified. However, quantifying new replacement halocarbons can be challenging, as mole fractions are generally low, requiring high measurement precision and low detection limits. In addition, calibration can be demanding, as calibration gases may not contain sufficiently high amounts of newly measured substances or the amounts in the calibration gas may have not been quantified. This paper presents an indirect data evaluation approach for TOF-MS data, where the calibration is linked to another compound which could be quantified in the calibration gas. We also present an approach to evaluate the quality of the indirect calibration method, select periods of stable instrument performance and determine well suited reference compounds. The method is applied to three short-lived synthetic halocarbons: HFO-1234yf, HFO-1234ze(E), and HCFO-1233zd(E). They represent replacements for longer-lived hydrofluorocarbons (HFCs) and exhibit increasing mole fractions in the atmosphere. The indirectly calibrated results are compared to directly calibrated measurements using data from TOF-MS canister sample analysis and TOF-MS in situ measurements, which are available for some periods of our dataset. The application of the indirect calibration method on several test cases can result in uncertainties of around 6 % to 11 %. For hydro(chloro-)fluoroolefines (denoted H(C)FOs), uncertainties up to 23 % are achieved. The indirectly calculated mole fractions of the investigated H(C)FOs at Taunus Observatory range between measured mole fractions at urban Dübendorf and Jungfraujoch stations in Switzerland.

scholarly journals Non-target analysis using gas chromatography with time-of-flight mass spectrometry: application to time series of fourth generation synthetic halocarbons at Taunus Observatory (Germany)

2021 ◽  
Author(s):  
Fides Lefrancois ◽  
Markus Jesswein ◽  
Markus Thoma ◽  
Andreas Engel ◽  
Kieran Stanley ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Trace Gases ◽  
Time Of Flight ◽  
Calibration Method ◽  
Data Set ◽  
Flight Mass Spectrometry ◽  
Calibration Gas ◽  
Tof Ms

Abstract. Production and use of many synthetic halogenated trace gases are regulated internationally because of their contribution to stratospheric ozone depletion or to climate change. In many applications they have been replaced by shorter-lived compounds which have become measurable in the atmosphere as emissions increased. Non-target monitoring of trace gases rather than targeted measurements of well-known substances is needed to keep up with such changes in the atmospheric composition. We regularly deploy gas chromatography (GC) coupled to time-of-flight mass spectrometry (TOF-MS) for analysis of flask air samples and in situ measurements at the Taunus Observatory, a site in central Germany. TOF-MS record data over a continuous mass range enable a retrospective analysis of the data set, which can thus be considered a type of digital air archive. This archive can be made use of if new substances come into use and their mass spectrometric fingerprint is identified. However, quantifying new replacement halocarbons can be challenging, as mole fractions are generally low, requiring high measurement precision and low detection limits. In addition, calibration can be demanding, as calibration gases may not contain sufficiently high amounts of newly used substances or the amounts in the calibration gas have not been quantified. This paper presents an indirect data evaluation approach for TOF-MS data, where the calibration is linked to another compound which could be quantified in the calibration gas. We also present an approach to evaluate the quality of the indirect calibration method and to select periods of stable instrument performance and well suited reference compounds. The method is applied to three short-lived synthetic halocarbons: HFO-1234-yf, HFO-1234ze(E), and HCFO-1233zd(E). They represent replacements for longer-lived HFCs and exhibit increasing mole fractions in the atmosphere. The indirectly calibrated results are compared to directly calibrated measurements using data from TOF-MS canister sample analysis and TOF-MS in situ measurements, which are available for some periods of our data set. The application of the indirect calibration method on several test cases can result into accuracies around 13 % to 20 %. For H(C)FOs accuracies up to 25 % are achieved. The indirectly calculated mole fractions of the investigated H(C)FOs at Taunus Observatory range between measured mole fractions at urban Dübendorf and Jungfraujoch stations in Switzerland.

scholarly journals First ground-based Fourier transform infrared (FTIR) spectrometer observations of HFC-23 at Rikubetsu, Japan, and Syowa Station, Antarctica

2021 ◽  
Vol 14 (9) ◽  
pp. 5955-5976
Author(s):  
Masanori Takeda ◽  
Hideaki Nakajima ◽  
Isao Murata ◽  
Tomoo Nagahama ◽  
Isamu Morino ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Fourier Transform Infrared ◽  
In Situ Measurements ◽  
Atmospheric Composition ◽  
Syowa Station ◽  
Spectroscopic Parameters ◽  
Dry Air ◽  
Systematic Uncertainties ◽  
Ftir Spectrometer

Abstract. We have developed a procedure for retrieving atmospheric abundances of HFC-23 (CHF3) with a ground-based Fourier transform infrared (FTIR) spectrometer and analyzed the spectra observed at Rikubetsu, Japan (43.5∘ N, 143.8∘ E), and at Syowa Station, Antarctica (69.0∘ S, 39.6∘ E). The FTIR retrievals were carried out with the SFIT4 retrieval program, and the two spectral windows of 1138.5–1148.0 cm−1 and 1154.0–1160.0 cm−1 in the overlapping ν2 and ν5 vibrational–rotational transition bands of HFC-23 were used to avoid strong H2O absorption features. We considered O3, N2O, CH4, H2O, HDO, CFC-12 (CCl2F2), HCFC-22 (CHClF2), peroxyacetyl nitrate (PAN) (CH3C(O)OONO2), HCFC-141b (CH3CCl2F), and HCFC-142b (CH3CClF2) to be interfering species. Vertical profiles of H2O, HDO, and CH4 are preliminarily retrieved with other independent spectral windows because these profiles may induce large uncertainties in the HFC-23 retrieval. Each HFC-23 retrieval has only one piece of vertical information with sensitivity to HFC-23 in the troposphere and the lower stratosphere. Retrieval errors mainly arise from the systematic uncertainties of the spectroscopic parameters used to obtain HFC-23, H2O, HDO, and CH4 abundances. For comparison between FTIR-retrieved HFC-23 total columns and surface dry-air mole fractions provided by AGAGE (Advanced Global Atmospheric Gases Experiment), FTIR-retrieved HFC-23 dry-air column-averaged mole fractions (XHFC-23) were calculated. The FTIR-retrieved XHFC-23 values at Rikubetsu and Syowa Station have negative biases of −15 % to −20 % and −25 % compared to the AGAGE datasets, respectively. These negative biases might mainly come from systematic uncertainties of HFC-23 spectroscopic parameters. The trend of the FTIR-retrieved XHFC-23 data at Rikubetsu was derived for December to February (DJF) observations, which are considered to represent the background values when an air mass reaching Rikubetsu has the least influence by transport of HFC-23 emissions from nearby countries. The DJF trend of Rikubetsu over the 1997–2009 period is 0.810 ± 0.093 ppt yr−1 (ppt: parts per trillion), which is in good agreement with the trend derived from the annual global mean datasets of the AGAGE 12-box model for the same period (0.820 ± 0.013 ppt yr−1). The DJF trend of Rikubetsu over the 2008–2019 period is 0.928 ± 0.108 ppt yr−1, which is consistent with the trend in the AGAGE in situ measurements at Trinidad Head (41.1∘ N, 124.2∘ W) for the same period (0.994 ± 0.001 ppt yr−1). The trend of the FTIR-retrieved XHFC-23 data at Syowa Station over the 2007–2016 period is 0.819 ± 0.071 ppt yr−1, which is consistent with that derived from the AGAGE in situ measurements at Cape Grim (40.7∘ S, 144.7∘ E) for the same period (0.874 ± 0.002 ppt yr−1). Although there are systematic biases in the FTIR-retrieved XHFC-23 at both sites, these results indicate that ground-based FTIR observations have the capability to monitor the long-term trend of atmospheric HFC-23. If this FTIR measurement technique were extended to other Network for the Detection of Atmospheric Composition Change (NDACC) ground-based FTIR sites around world, the measurements reported from these sites would complement the global AGAGE observations by filling spatial and temporal gaps and may lead to improved insights about changes in regional and global emissions of HFC-23 and its role in global warming.

In situ measurements of microphysical properties and trace gases in two cumulonimbus anvils over western Europe

1999 ◽  
Vol 104 (D10) ◽  
pp. 12221-12226 ◽  
Author(s):  
Johan Ström ◽  
Horst Fischer ◽  
Jos Lelieveld ◽  
Franz Schröder
Keyword(s):  
Western Europe ◽  
Trace Gases ◽  
In Situ Measurements ◽  
Microphysical Properties

scholarly journals MIPAS-STR measurements in the Arctic UTLS in winter/spring 2010: instrument characterization, retrieval and validation

2012 ◽  
Vol 5 (6) ◽  
pp. 1205-1228 ◽  
Author(s):  
W. Woiwode ◽  
H. Oelhaf ◽  
T. Gulde ◽  
C. Piesch ◽  
G. Maucher ◽  
...  
Keyword(s):  
Cross Sections ◽  
Stratospheric Ozone ◽  
Trace Gases ◽  
Michelson Interferometer ◽  
Polar Vortex ◽  
The Arctic ◽  
Radiometric Calibration ◽  
Mid Infrared ◽  
Mean Differences

Abstract. The mid-infrared FTIR-limb-sounder Michelson Interferometer for Passive Atmospheric Sounding–STRatospheric aircraft (MIPAS-STR) was deployed onboard the research aircraft M55 Geophysica during the RECONCILE campaign (Reconciliation of Essential Process Parameters for an Enhanced Predictability of Arctic Stratospheric Ozone Loss and its Climate Interactions) in the Arctic winter/spring 2010. From the MIPAS-STR measurements, vertical profiles and 2-dimensional vertical cross-sections of temperature and trace gases are retrieved. Detailed mesoscale structures of polar vortex air, extra vortex air and vortex filaments are identified in the results at typical vertical resolutions of 1 to 2 km and typical horizontal sampling densities of 45 or 25 km, depending on the sampling programme. Results are shown for the RECONCILE flight 11 on 2 March 2010 and are validated with collocated in-situ measurements of temperature, O3, CFC-11, CFC-12 and H2O. Exceptional agreement is found for the in-situ comparisons of temperature and O3, with mean differences (vertical profile/along flight track) of 0.2/−0.2 K for temperature and −0.01/0.05 ppmv for O3 and corresponding sample standard deviations of the mean differences of 0.7/0.6 K and 0.1/0.3 ppmv. The comparison of the retrieved vertical cross-sections of HNO3 from MIPAS-STR and the infrared limb-sounder Cryogenic Infrared Spectrometers and Telescopes for the Atmosphere–New Frontiers (CRISTA–NF) indicates a high degree of agreement. We discuss MIPAS-STR in its current configuration, the spectral and radiometric calibration of the measurements and the retrieval of atmospheric parameters from the spectra. The MIPAS-STR measurements are significantly affected by continuum-like contributions, which are attributed to background aerosol and broad spectral signatures from interfering trace gases, and are important for mid-infrared limb-sounding in the Upper Troposphere/Lower Stratosphere (UTLS) region. Taking into consideration continuum-like effects, we present a scheme suitable for accurate retrievals of temperature and an extended set of trace gases, including the correction of a systematic line-of-sight offset.

Das ACTRIS-Kalibrierzentrum für Stickoxid-Messungen am Forschungszentrum Jülich

2021 ◽  
Author(s):  
Max Gerrit Adam ◽  
Robert Wegener ◽  
Franz Rohrer ◽  
Ralf Tillmann ◽  
Astrid Kiendler-Scharr ◽  
...  
Keyword(s):  
Phase Shift ◽  
Diode Laser ◽  
Trace Gases ◽  
In Situ Measurements ◽  
Tunable Diode Laser ◽  
Research Infrastructure ◽  
Aerosol Cloud ◽  
Reactive Trace Gases

<p>Langzeitmessungen der atmosphärischen Zusammensetzung sind von zentraler Bedeutung, um die Atmosphärenchemie und den Klimawandel zu verstehen. ACTRIS (Aerosol, Cloud and Trace Gases Research Infrastructure) hat sich zum Ziel gesetzt, ein europaweites Netzwerk von Beobachtungsstationen aufzubauen, die qualitativ hochwertige Daten und Informationen zu kurzlebigen atmosphärischen Bestandteilen liefern und für Nutzer auf der ganzen Welt offen zugänglich machen. Stickstoffmonoxid (NO) und Stickstoffdioxid (NO<sub>2</sub>), die sogenannten Stickoxide (NO<sub>x</sub>), spielen eine Schlüsselrolle in der Atmosphärenchemie, da sie zur Bildung von troposphärischem Ozon, Smog und saurem Regen beitragen. Darüber hinaus ist die kurz- und langfristige Exposition mit NO<sub>2</sub> mit negativen Auswirkungen auf das menschliche Atmungssystem in Verbindung gebracht worden. Die Hauptquellen von NO<sub>x</sub> in bewohnten Gebieten sind Verbrennungsprozesse, z.B. von Fahrzeugen und bei industriellen Aktivitäten. NO<sub>x</sub>-Messungen werden derzeit meist indirekt über Chemilumineszenz-Instrumente durchgeführt, die Korrekturen für Feuchte und Ozon erfordern. Jüngste technologische Fortschritte (z. B. Cavity Attenuated Phase Shift, CAPS, oder Tunable Diode Laser Systeme) erlauben die direkte Detektion von NO<sub>x</sub>-Komponenten, was Interferenzen vermeidet, die durch die Umwandlung von NO<sub>2</sub> in NO hervorgerufen werden. Messvergleiche zeigen aber, dass auch hier neben bekannten Problemen wie Reaktionen in den Einlassleitungen auch unerwartete Artefakte beobachtet werden können. Messvergleiche aber zeigen auch hier, dass neben bekannten Problemen wie Reaktionen in den Einlassleitungen auch unerwartete auftreten können. Um genaue und präzise NO<sub>x</sub> Messungen mit einer Vielzahl von NO<sub>x</sub>-Messsystemen in verschiedenen Stationen sicherzustellen, müssen neben der Standardisierung von Messprotokollen und Kalibrierungsverfahren auch an zentraler Stelle durch Messvergleiche und Auditierungen Unterschiede der verschiedenen Messverfahren dokumentiert werden.</p> <p>ACTRIS setzt sich aus central facilities (CFs) und national facilities (NFs) zusammen. Die NFs bilden den explorativen und beobachtenden Teil der Forschungsinfrastruktur. Die CFs sind von grundlegender Bedeutung für die Bereitstellung von harmonisierten und hochpräzisen Daten und stellen eine Vielzahl von Dienstleistungen zur Verfügung. Eines der CFs ist das Reactive Trace Gases In Situ Measurements (CiGas), das für die Überwachung der Datenqualität reaktiver Spurengase verantwortlich ist. Für die Qualitätssicherung (QA) und Qualitätskontrolle (QC) der Stickoxidmessungen an den NFs innerhalb von CiGas ist das Forschungszentrum Jülich (FZJ) zuständig, das auch das World Calibration Center (WCC) für Stickoxide im Global Atmosphere Watch (GAW) Netzwerk beheimatet. Seine Aufgaben umfassen i) die Verbindung von Spurengasmessungen von ACTRIS mit denen anderer Netzwerke, ii) die Beratung und Organisation von Schulungen, iii) die Bereitstellung von Mess- und Auswerteverfahren, iv) das Labelling und die Auditierung von NFs, v) die Implementierung neuer wissenschaftlicher und technologischer Entwicklungen.</p> <p>Es ist vorgesehen, bis 2025 ein zertifiziertes und funktionsfähiges Netzwerk von ACTRIS-Stationen aufzubauen. Es soll der wissenschaftlichen Gemeinschaft qualitativ hochwertige Daten liefern, die die Grundlage für fundierte Entscheidungen der politischen Entscheidungsträger bilden können.</p>

scholarly journals In situ measurements of stratospheric ozone depletion rates in the Arctic winter 1991/1992: A Lagrangian approach

1998 ◽  
Vol 103 (D5) ◽  
pp. 5843-5853 ◽  
Author(s):  
M. Rex ◽  
P. von der Gathen ◽  
N. R. P. Harris ◽  
D. Lucic ◽  
B. M. Knudsen ◽  
...  
Keyword(s):  
Ozone Depletion ◽  
Stratospheric Ozone ◽  
In Situ Measurements ◽  
Lagrangian Approach ◽  
The Arctic ◽  
Stratospheric Ozone Depletion

scholarly journals Maïdo observatory: a new high-altitude station facility at Reunion Island (21° S, 55° E) for long-term atmospheric remote sensing and in situ measurements

2013 ◽  
Vol 6 (10) ◽  
pp. 2865-2877 ◽  
Author(s):  
J.-L. Baray ◽  
Y. Courcoux ◽  
P. Keckhut ◽  
T. Portafaix ◽  
P. Tulet ◽  
...  
Keyword(s):  
High Altitude ◽  
Southern Hemisphere ◽  
Marine Boundary Layer ◽  
In Situ Measurements ◽  
Atmospheric Composition ◽  
Reunion Island ◽  
Atmospheric Measurements ◽  
Atmospheric Remote Sensing ◽  
Réunion Island

Abstract. Since the nineties, atmospheric measurement systems have been deployed at Reunion Island, mainly for monitoring the atmospheric composition in the framework of NDSC/NDACC (Network for the Detection of Stratospheric Change/Network for the Detection of Atmospheric Composition Change). The location of Reunion Island presents a great interest because there are very few multi-instrumented stations in the tropics and particularly in the southern hemisphere. In 2012, a new observatory was commissioned in Maïdo at 2200 m above sea level: it hosts various instruments for atmospheric measurements, including lidar systems, spectro-radiometers and in situ gas and aerosol measurements. This new high-altitude Maïdo station provides an opportunity: 1. to improve the performance of the optical instruments above the marine boundary layer, and to open new perspectives on upper troposphere and lower stratosphere studies; 2. to develop in situ measurements of the atmospheric composition for climate change surveys, in a reference site in the tropical/subtropical region of the southern hemisphere; 3. to offer trans-national access to host experiments or measurement campaigns for focused process studies.

scholarly journals Very high stratospheric influence observed in the free troposphere over the northern Alps – just a local phenomenon?

2020 ◽  
Vol 20 (1) ◽  
pp. 243-266 ◽  
Author(s):  
Thomas Trickl ◽  
Hannes Vogelmann ◽  
Ludwig Ries ◽  
Michael Sprenger
Keyword(s):  
Stratospheric Ozone ◽  
Atmospheric Composition ◽  
Radiosonde Data ◽  
Free Troposphere ◽  
Stratospheric Intrusion ◽  
Lidar Measurements ◽  
Range Transport ◽  
Summer Minimum ◽  
Very High

Abstract. The atmospheric composition is strongly influenced by a change in atmospheric dynamics, which is potentially related to climate change. A prominent example is the doubling of the stratospheric ozone component at the Zugspitze summit station (2962 m a.s.l., Garmisch-Partenkirchen, Germany) between the mid-seventies and 2005, roughly from 11 to 23 ppb (43 %). Systematic efforts for identifying and quantifying this influence have been made since the late 1990s. Meanwhile, routine lidar measurements of ozone and water vapour carried out at Garmisch-Partenkirchen (German Alps) since 2007, combined with in situ and radiosonde data and trajectory calculations, have revealed that stratospheric intrusion layers are present on 84 % of the yearly measurement days. At Alpine summit stations the frequency of intrusions exhibits a seasonal cycle with a pronounced summer minimum that is reproduced by the lidar measurements. The summer minimum disappears if one looks at the free troposphere as a whole. The mid- and upper-tropospheric intrusion layers seem to be dominated by very long descent on up to hemispheric scale in an altitude range starting at about 4.5 km a.s.l. Without interfering air flows, these layers remain very dry, typically with RH ≤5 % at the centre of the intrusion. Pronounced ozone maxima observed above Garmisch-Partenkirchen have been mostly related to a stratospheric origin rather than to long-range transport from remote boundary layers. Our findings and results for other latitudes seem to support the idea of a rather high contribution of ozone import from the stratosphere to tropospheric ozone.

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