scholarly journals Measurement report: Methane (CH<sub>4</sub>) sources in Krakow, Poland: insights from isotope analysis

2021 ◽  
Author(s):  
Malika Menoud ◽  
Carina van der Veen ◽  
Jaroslaw Necki ◽  
Jakub Bartyzel ◽  
Barbara Szénási ◽  
...  
Keyword(s):  
Time Series ◽  
Isotopic Composition ◽  
Transport Model ◽  
Isotope Analysis ◽  
Ambient Air ◽  
Coal Extraction ◽  
Night Time ◽  
Isotopic Signatures ◽  
Ch4 Emissions ◽  
Gas Leaks

Abstract. Methane (CH4) emissions from human activities are a threat to the resilience of our current climate system, and to the adherence of the Paris Agreement goals. The stable isotopic composition of methane (δ13C and δ2H) allows to distinguish between the different CH4 origins. A significant part of the European CH4 emissions, 3.6 % in 2018, comes from coal extraction in Poland; the Upper Silesian Coal Basin (USCB) being the main hotspot. Measurements of CH4 mole fraction (χ(CH4)), δ13C and δ2H in CH4 in ambient air were performed continuously during 6 months in 2018 and 2019 at Krakow, Poland, 50 km east of the USCB. In addition, air samples were collected during parallel mobile campaigns, from multiple CH4 sources in the footprint area of the continuous measurements. The resulting isotopic signatures from sampled plumes allowed us to distinguish between natural gas leaks, coal mine fugitive emissions, landfill and sewage, and ruminants. The use of δ2H in CH4 is crucial to distinguish the fossil fuel emissions in the case of Krakow, because their relatively depleted δ13C values overlap with the ones of microbial sources. The observed χ(CH4) time series showed regular daily night-time accumulations, sometimes combined with irregular pollution events during the day. The isotopic signatures of each peak were obtained using the Keeling plot method, and generally fall in the range of thermogenic CH4 formation – with δ13C between −55.3 and −39.4 ‰ V-PDB, and δ2H between −285 and −124 ‰ V-SMOW. They compare well with the signatures measured for gas leaks in Krakow and USCB mines. The CHIMERE transport model was used to compute the CH4 and isotopic composition time series in Krakow, based on two emission inventories. The χ(CH4) are generally under-estimated in the model. The simulated isotopic source signatures, obtained with Keeling plots on each simulated peak using the EDGAR v5.0 inventory, indicate that a higher contribution from fuel combustion sources in EDGAR would lead to a better agreement. The isotopic mismatches between model and observations are mainly caused by uncertainties in the assigned isotopic signatures for each source category, and the way they are classified in the inventory. These uncertainties are larger for emissions close to the study site, which are more heterogenous than the ones advected from the USCB coal mines. Our isotope approach proves to be very sensitive in this region, thus helping to evaluate emission estimates.

scholarly journals Methane (CH<sub>4</sub>) sources in Krakow, Poland: insights from isotope analysis

2021 ◽  
Vol 21 (17) ◽  
pp. 13167-13185
Author(s):  
Malika Menoud ◽  
Carina van der Veen ◽  
Jaroslaw Necki ◽  
Jakub Bartyzel ◽  
Barbara Szénási ◽  
...  
Keyword(s):  
Time Series ◽  
Isotopic Composition ◽  
Transport Model ◽  
Ambient Air ◽  
Coal Extraction ◽  
Night Time ◽  
Isotopic Signatures ◽  
Ch4 Emissions ◽  
Gas Leaks ◽  
Pollution Events

Abstract. Methane (CH4) emissions from human activities are a threat to the resilience of our current climate system. The stable isotopic composition of methane (δ13C and δ2H) allows us to distinguish between the different CH4 origins. A significant part of the European CH4 emissions, 3.6 % in 2018, comes from coal extraction in Poland, the Upper Silesian Coal Basin (USCB) being the main hotspot. Measurements of CH4 mole fraction (χ(CH4)), δ13C, and δ2H in CH4 in ambient air were performed continuously during 6 months in 2018 and 2019 at Krakow, Poland, in the east of the USCB. In addition, air samples were collected during parallel mobile campaigns, from multiple CH4 sources in the footprint area of the continuous measurements. The resulting isotopic signatures from sampled plumes allowed us to distinguish between natural gas leaks, coal mine fugitive emissions, landfill and sewage, and ruminants. The use of δ2H in CH4 is crucial to distinguish the fossil fuel emissions in the case of Krakow because their relatively depleted δ13C values overlap with the ones of microbial sources. The observed χ(CH4) time series showed regular daily night-time accumulations, sometimes combined with irregular pollution events during the day. The isotopic signatures of each peak were obtained using the Keeling plot method and generally fall in the range of thermogenic CH4 formation – with δ13C between −59.3 ‰ and −37.4 ‰ Vienna Pee Dee Belemnite (V-PDB) and δ2H between −291 ‰ and −137 ‰ Vienna Standard Mean Ocean Water (V-SMOW). They compare well with the signatures measured for gas leaks in Krakow and USCB mines. The CHIMERE transport model was used to compute the CH4 and isotopic composition time series in Krakow, based on two emission inventories. The magnitude of the pollution events is generally underestimated in the model, which suggests that emission rates in the inventories are too low. The simulated isotopic source signatures, obtained with Keeling plots on each simulated peak, indicate that a higher contribution from fuel combustion sources in the EDGAR v5.0 inventory would lead to a better agreement than when using CAMS-REG-GHG v4.2 (Copernicus Atmosphere Monitoring Service REGional inventory for Air Pollutants and GreenHouse Gases). The isotopic mismatches between model and observations are mainly caused by uncertainties in the assigned isotopic signatures for each source category and the way they are classified in the inventory. These uncertainties are larger for emissions close to the study site, which are more heterogenous than the ones advected from the USCB coal mines. Our isotope approach proves to be very sensitive in this region, thus helping to evaluate emission estimates.

Isotopic characterisation of methane emissions from Krakow, Poland

2021 ◽  
Author(s):  
Malika Menoud ◽  
Carina van der Veen ◽  
Jaroslaw Necki ◽  
Mila Stanisavljevic ◽  
Barbara Szenási ◽  
...  
Keyword(s):  
Time Series ◽  
Transport Model ◽  
Ambient Air ◽  
Night Time ◽  
Isotopic Signatures ◽  
Upper Silesian Coal Basin ◽  
Source Category ◽  
Footprint Area ◽  
Gas Leaks ◽  
Pollution Events

&lt;p&gt;Methane (CH&lt;sub&gt;4&lt;/sub&gt;) emissions from human activities are a threat to the resilience of our current climate, and to the adherence of the Paris Agreement goals. The stable isotopic composition of methane (&amp;#948;&lt;sup&gt;13&lt;/sup&gt;C and &amp;#948;&lt;sup&gt;2&lt;/sup&gt;H) allows to distinguish between the different CH&lt;sub&gt;4&lt;/sub&gt; origins. A significant part of the European CH&lt;sub&gt;4&lt;/sub&gt; emissions, 10 % in 2016, comes from the Upper Silesian Coal Basin (USCB).&amp;#160;&lt;/p&gt;&lt;p&gt;Measurements of CH&lt;sub&gt;4&lt;/sub&gt; mole fraction (&amp;#967;(CH&lt;sub&gt;4&lt;/sub&gt;)), &amp;#948;&lt;sup&gt;13&lt;/sup&gt;C and &amp;#948;&lt;sup&gt;2&lt;/sup&gt;H&amp;#160;in CH&lt;sub&gt;4&lt;/sub&gt; in ambient air were performed continuously during 6 months in 2018 and 2019 at Krakow, Poland. In addition, CH&lt;sub&gt;4&lt;/sub&gt; samples were collected during parallel mobile campaigns, from multiple CH&lt;sub&gt;4&lt;/sub&gt; sources in the footprint area of continuous measurements. The resulting isotopic signatures from natural gas leaks, coal mine fugitive emissions, landfill and sewage, and ruminant emissions were statistically different. The use of &amp;#948;&lt;sup&gt;2&lt;/sup&gt;H in CH&lt;sub&gt;4&lt;/sub&gt; is crucial to distinguish the fossil fuel emissions in the case of Krakow, because their relatively depleted &amp;#948;&lt;sup&gt;13&lt;/sup&gt;C values overlap with the ones of microbial sources. The observed &amp;#967;(CH&lt;sub&gt;4&lt;/sub&gt;) time series showed a regular daily night-time accumulations, sometimes combined with irregular pollution events during the day. The isotopic signatures of each peak were obtained using the Keeling plot method, and generally fall in the range of thermogenic CH&lt;sub&gt;4&lt;/sub&gt; formation, with &amp;#948;&lt;sup&gt;13&lt;/sup&gt;C between -55.3 and -39.4 &amp;#8240; V-PDB, and &amp;#948;&lt;sup&gt;2&lt;/sup&gt;H between -285 and -124&amp;#160;&amp;#8240;&amp;#160;V-SMOW. They compare well with the signatures measured for gas leaks in Krakow and USCB mines.&amp;#160;&lt;/p&gt;&lt;p&gt;The CHIMERE transport model was used to compute the CH&lt;sub&gt;4&lt;/sub&gt; time series at the study location, based on two emission inventories. The &amp;#967;(CH&lt;sub&gt;4&lt;/sub&gt;) are generally under-estimated in the model. The isotopic signatures of all pollution events over the entire time periods were extracted from Keeling plots applied on each peaks, for both observed and modelled time series using the EDGAR v5.0 inventory. The results indicate that a higher contribution from fuel combustion sources in the inventory would lead to a better agreement. The isotopic mismatches between model and observations are mainly caused by uncertainties in the assigned isotopic signatures for each source category, and how they are classified in the inventory. These uncertainties are larger for emissions close to the study site, which are more heterogenous than the ones advected from the USCB coal mines. Our isotope approach proves here to be very sensitive in this region, thus helping to improve emission estimates.&lt;/p&gt;

Evaluation of continuous δ13CH4 measurements in Heidelberg and at Schauinsland, Germany

2020 ◽  
Author(s):  
Antje Hoheisel ◽  
Frank Meinhardt ◽  
Martina Schmidt
Keyword(s):  
Isotopic Composition ◽  
Mole Fraction ◽  
Isotope Analysis ◽  
Ambient Air ◽  
Peak Height ◽  
West Germany ◽  
Livestock Farming ◽  
Biogenic Methane ◽  
The Mean ◽  
Instrumental Development

&lt;p&gt;Instrumental development in measurement technique now allows continuous in-situ isotope analysis of &lt;sup&gt;13&lt;/sup&gt;CH&lt;sub&gt;4&lt;/sub&gt; by Cavity Ring-Down Spectroscopy (CRDS). Analyses of the isotopic composition of methane in ambient air can potentially be used to partition between different CH&lt;sub&gt;4&lt;/sub&gt; source categories.&lt;/p&gt;&lt;p&gt;Since 2014 a CRDS G2201-i analyser has been used to continuously measure CH&lt;sub&gt;4&lt;/sub&gt; and its &lt;sup&gt;13&lt;/sup&gt;C/&lt;sup&gt;12&lt;/sup&gt;C ratio in ambient air at the Institute of Environmental Physics (IUP) in Heidelberg (116m a.s.l.), South-West Germany. Furthermore, the CRDS G2201-i analyser was installed twice for a month at the measurement station of the German Environment Agency at Schauinsland (1205m a.s.l.). In September 2018 and in February 2019 the analyser was moved to Schauinsland to examine the validity of evaluations of continuous &amp;#948;&lt;sup&gt;13&lt;/sup&gt;CH&lt;sub&gt;4 &lt;/sub&gt;measurements at a semi-rural station.&lt;/p&gt;&lt;p&gt;As an urban station, the seasonal and daily variations of the measured CH&lt;sub&gt;4&lt;/sub&gt; mole fraction and isotopic composition in Heidelberg vary much stronger than at the mountain station Schauinsland. The precision of the isotopic source signature calculation using a Keeling plot strongly depends on the CH&lt;sub&gt;4&lt;/sub&gt; peak height and instrumental precision. Therefore, at Schauinsland station the lower variability in the CH&lt;sub&gt;4&lt;/sub&gt; mole fraction makes the evaluation challenging. Different methods such as monthly/weekly interval evaluations and moving Keeling/Miller Tans methods has been used to calculate the isotopic source signature in ambient air.&lt;/p&gt;&lt;p&gt;The isotopic methane source signatures of the air in Heidelberg was found to be between -75 &amp;#8240; and -35 &amp;#8240;, with an average of (-54 &amp;#177; 2) &amp;#8240;. An annual cycle can be noticed with more depleted values (-56 &amp;#8240;) in summer and more enriched values (-51 &amp;#8240;) in winter, due to larger biogenic emissions in summer and more thermogenic (e.g. natural gas) emissions in winter. The mean isotopic source signature calculated at Schauinsland shows variations, too, with more enriched values (&amp;#8722;56 &amp;#8240;) in winter and more depleted (&amp;#8722;60 &amp;#8240;) ones in autumn. The more depleted values in summer/autumn at Schauinsland corresponds to more biogenic methane and can be explained by dairy cows grazing near the station especially during this time.&lt;/p&gt;&lt;p&gt;The generally more enriched values at Schauinsland are caused by the more rural surrounding. Emission estimates of county provided by the LUBW Landesanstalt f&amp;#252;r Umwelt Baden-W&amp;#252;rttemberg shows that around Schauinsland 60 % of the CH&lt;sub&gt;4&lt;/sub&gt; emissions are emitted by livestock farming and around Heidelberg only 28 %. The mean isotopic source signature calculated using these emissions is (-58 &amp;#177; 2) &amp;#8240; for Schauinsland and (-53 &amp;#177; 2) &amp;#8240; for Heidelberg. These results agreed well with the mean source signatures determined out of continuous isotopic measurements.&lt;/p&gt;

Reconstructed Paleodiets and Subsistence Strategies of the Central Ciscaucasian Population (1000 BC to 1000 AD), Based on Collagen Isotope Analysis of Bone Samples from the Kichmalka II Burial Ground

2022 ◽  
Vol 49 (4) ◽  
pp. 80-90
Author(s):  
A. N. Babenko ◽  
M. V. Dobrovolskaya ◽  
E. E. Vasilyeva ◽  
D. S. Korobov
Keyword(s):  
Isotopic Composition ◽  
Iron Age ◽  
Nitrogen Isotopes ◽  
Isotope Analysis ◽  
Bone Collagen ◽  
North Caucasus ◽  
Anthropogenic Effect ◽  
Isotopic Signatures ◽  
Carbon And Nitrogen ◽  
Animal Bone

Settlement and economy patterns of the Iron Age and early medieval population of the Central North Caucasus evidence complex cultural processes in the region. The ecological approach including the evaluation of carbon and nitrogen isotopes in the local biota opens up new prospects in the study of environments, climate, anthropogenic effect, land use, and nutrition. We analyze the isotopic composition of collagen in 19 human and 11 animal bone samples from Kichmalka II—a cemetery successively used by the Koban people, those of the Sarmatian stage, and Alans. The isotopic composition of the Alanian sample indicates a heavy predominance of plants with the C3-type photosynthesis in the diet of humans and animals. People who lived during the Koban and Sarmatian stages consumed also C4-plants, such as common millet (Panicum miliaceum), suggesting the rise of the trophic step for carbon (Δδ13Chuman-animal). Statistically signifi cant differences in the isotopic composition of carbon were found within the Koban population, apparently evidencing two dietary models. The Δδ15Nhuman-animal values fall within the trophic step, mirroring a focus on meat and dairy products in the diet of all groups. Comparison with respective data on the Klin-Yar III cemetery revealed differences in isotopic signatures in the diet of both humans and domestic animals during the Koban period. The possible reason is climatic change in the Iron Age and the variable share of millet in the diet of the Koban people. The low proportion of δ15N (below 4 ‰) in the bone collagen of goat, sheep, and horse of the Alanian period may attest to vertical transhumance.

scholarly journals Real-time analysis of <i>δ</i><sup>13</sup>C- and <i>δ</i>D-CH<sub>4</sub> in ambient air with laser spectroscopy: method development and first intercomparison results

2016 ◽  
Vol 9 (1) ◽  
pp. 263-280 ◽  
Author(s):  
S. Eyer ◽  
B. Tuzson ◽  
M. E. Popa ◽  
C. van der Veen ◽  
T. Röckmann ◽  
...  
Keyword(s):  
Isotopic Composition ◽  
Real Time ◽  
Method Development ◽  
Isotope Analysis ◽  
Isotope Ratio Mass Spectrometry ◽  
Ambient Air ◽  
Repeated Measurements ◽  
Laser Absorption ◽  
Real Time Analysis

Abstract. In situ and simultaneous measurement of the three most abundant isotopologues of methane using mid-infrared laser absorption spectroscopy is demonstrated. A field-deployable, autonomous platform is realized by coupling a compact quantum cascade laser absorption spectrometer (QCLAS) to a preconcentration unit, called trace gas extractor (TREX). This unit enhances CH4 mole fractions by a factor of up to 500 above ambient levels and quantitatively separates interfering trace gases such as N2O and CO2. The analytical precision of the QCLAS isotope measurement on the preconcentrated (750 ppm, parts-per-million, µmole mole−1) methane is 0.1 and 0.5 ‰ for δ13C- and δD-CH4 at 10 min averaging time. Based on repeated measurements of compressed air during a 2-week intercomparison campaign, the repeatability of the TREX–QCLAS was determined to be 0.19 and 1.9 ‰ for δ13C and δD-CH4, respectively. In this intercomparison campaign the new in situ technique is compared to isotope-ratio mass spectrometry (IRMS) based on glass flask and bag sampling and real time CH4 isotope analysis by two commercially available laser spectrometers. Both laser-based analyzers were limited to methane mole fraction and δ13C-CH4 analysis, and only one of them, a cavity ring down spectrometer, was capable to deliver meaningful data for the isotopic composition. After correcting for scale offsets, the average difference between TREX–QCLAS data and bag/flask sampling–IRMS values are within the extended WMO compatibility goals of 0.2 and 5 ‰ for δ13C- and δD-CH4, respectively. This also displays the potential to improve the interlaboratory compatibility based on the analysis of a reference air sample with accurately determined isotopic composition.

scholarly journals Real-time analysis of δ<sup>13</sup>C- and δD-CH<sub>4</sub> in ambient air with laser spectroscopy: method development and first intercomparison results

2015 ◽  
Vol 8 (8) ◽  
pp. 8925-8970 ◽  
Author(s):  
S. Eyer ◽  
B. Tuzson ◽  
M. E. Popa ◽  
C. van der Veen ◽  
T. Röckmann ◽  
...  
Keyword(s):  
Isotopic Composition ◽  
Real Time ◽  
Method Development ◽  
Isotope Analysis ◽  
Isotope Ratio Mass Spectrometry ◽  
Ambient Air ◽  
Laser Absorption ◽  
Real Time Analysis ◽  
Averaging Time

Abstract. In situ and simultaneous measurement of the three most abundant isotopologues of methane using mid-infrared laser absorption spectroscopy is demonstrated. A field-deployable, autonomous platform is realized by coupling a compact quantum cascade laser absorption spectrometer (QCLAS) to a preconcentration unit, called TRace gas EXtractor (TREX). This unit enhances CH4 mole fractions by a factor of up to 500 above ambient levels and quantitatively separates interfering trace gases such as N2O and CO2. The analytical precision of the QCLAS isotope measurement on the preconcentrated (750 ppm, parts-per-million, μmole/mole) methane is 0.1 and 0.5 ‰ for δ13C- and δD-CH4 at 10 min averaging time. Based on replicate measurements of compressed air during a two-week intercomparison campaign, the repeatability of the TREX-QCLAS was determined to be 0.19 and 1.9 ‰ for δ13C and δD-CH4, respectively. In this intercomparison campaign the new in situ technique is compared to isotope-ratio mass-spectrometry (IRMS) based on glass flask and bag sampling and real time CH4 isotope analysis by two commercially available laser spectrometers. Both laser-based analyzers were limited to methane mole fraction and δ13C-CH4 analysis, and only one of them, a cavity ring down spectrometer, was capable to deliver meaningful data for the isotopic composition. After correcting for scale offsets, the average difference between TREX–QCLAS data and bag/flask sampling–IRMS values are within the extended WMO compatibility goals of 0.2 and 5 ‰ for δ13C- and δD-CH4, respectively. Thus, the intercomparison also reveals the need for reference air samples with accurately determined isotopic composition of CH4 to further improve the interlaboratory compatibility.

scholarly journals Measuring and modelling the isotopic composition of soil respiration: insights from a grassland tracer experiment

2011 ◽  
Vol 8 (5) ◽  
pp. 1333-1350 ◽  
Author(s):  
U. Gamnitzer ◽  
A. B. Moyes ◽  
D. R. Bowling ◽  
H. Schnyder
Keyword(s):  
Steady State ◽  
Isotopic Composition ◽  
Transport Model ◽  
Tracer Experiment ◽  
Atmospheric Co2 ◽  
Soil Co2 ◽  
Soil Air ◽  
Co2 Transport ◽  
Atmosphere System

Abstract. The carbon isotopic composition (δ13C) of CO2 efflux (δ13Cefflux) from soil is generally interpreted to represent the actual isotopic composition of the respiratory source (δ13CRs). However, soils contain a large CO2 pool in air-filled pores. This pool receives CO2 from belowground respiration and exchanges CO2 with the atmosphere (via diffusion and advection) and the soil liquid phase (via dissolution). Natural or artificial modification of δ13C of atmospheric CO2 (δ13Catm) or δ13CRs causes isotopic disequilibria in the soil-atmosphere system. Such disequilibria generate divergence of δ13Cefflux from δ13CRs (termed "disequilibrium effect"). Here, we use a soil CO2 transport model and data from a 13CO2/12CO2 tracer experiment to quantify the disequilibrium between δ13Cefflux and δ13CRs in ecosystem respiration. The model accounted for diffusion of CO2 in soil air, advection of soil air, dissolution of CO2 in soil water, and belowground and aboveground respiration of both 12CO2 and 13CO2 isotopologues. The tracer data were obtained in a grassland ecosystem exposed to a δ13Catm of −46.9 ‰ during daytime for 2 weeks. Nighttime δ13Cefflux from the ecosystem was estimated with three independent methods: a laboratory-based cuvette system, in-situ steady-state open chambers, and in-situ closed chambers. Earlier work has shown that the δ13Cefflux measurements of the laboratory-based and steady-state systems were consistent, and likely reflected δ13CRs. Conversely, the δ13Cefflux measured using the closed chamber technique differed from these by −11.2 ‰. Most of this disequilibrium effect (9.5 ‰) was predicted by the CO2 transport model. Isotopic disequilibria in the soil-chamber system were introduced by changing δ13Catm in the chamber headspace at the onset of the measurements. When dissolution was excluded, the simulated disequilibrium effect was only 3.6 ‰. Dissolution delayed the isotopic equilibration between soil CO2 and the atmosphere, as the storage capacity for labelled CO2 in water-filled soil pores was 18 times that of soil air. These mechanisms are potentially relevant for many studies of δ13CRs in soils and ecosystems, including FACE experiments and chamber studies in natural conditions. Isotopic disequilibria in the soil-atmosphere system may result from temporal variation in δ13CRs or diurnal changes in the mole fraction and δ13C of atmospheric CO2. Dissolution effects are most important under alkaline conditions.

Imputing missing data in non-renewable empower time series from night-time lights observations

2018 ◽  
Vol 84 ◽  
pp. 106-118 ◽  
Author(s):  
Laura Neri ◽  
Luca Coscieme ◽  
Biagio F. Giannetti ◽  
Federico M. Pulselli
Keyword(s):  
Time Series ◽  
Missing Data ◽  
Night Time
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