Artykuły w czasopismach: „Picarro”

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Yang, Mingxi, John Prytherch, Elena Kozlova, Margaret J. Yelland, Deepulal Parenkat Mony i Thomas G. Bell. "Comparison of two closed-path cavity-based spectrometers for measuring air–water CO2 and CH4 fluxes by eddy covariance". Atmospheric Measurement Techniques 9, nr 11 (18.11.2016): 5509–22. http://dx.doi.org/10.5194/amt-9-5509-2016.

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Abstract. In recent years several commercialised closed-path cavity-based spectroscopic instruments designed for eddy covariance flux measurements of carbon dioxide (CO2), methane (CH4), and water vapour (H2O) have become available. Here we compare the performance of two leading models – the Picarro G2311-f and the Los Gatos Research (LGR) Fast Greenhouse Gas Analyzer (FGGA) at a coastal site. Both instruments can compute dry mixing ratios of CO2 and CH4 based on concurrently measured H2O, temperature, and pressure. Additionally, we used a high throughput Nafion dryer to physically remove H2O from the Picarro airstream. Observed air–sea CO2 and CH4 fluxes from these two analysers, averaging about 12 and 0.12 mmol m−2 day−1 respectively, agree within the measurement uncertainties. For the purpose of quantifying dry CO2 and CH4 fluxes downstream of a long inlet, the numerical H2O corrections appear to be reasonably effective and lead to results that are comparable to physical removal of H2O with a Nafion dryer in the mean. We estimate the high-frequency attenuation of fluxes in our closed-path set-up, which was relatively small ( ≤ 10 %) for CO2 and CH4 but very large for the more polar H2O. The Picarro showed significantly lower noise and flux detection limits than the LGR. The hourly flux detection limit for the Picarro was about 2 mmol m−2 day−1 for CO2 and 0.02 mmol m−2 day−1 for CH4. For the LGR these detection limits were about 8 and 0.05 mmol m−2 day−1. Using global maps of monthly mean air–sea CO2 flux as reference, we estimate that the Picarro and LGR can resolve hourly CO2 fluxes from roughly 40 and 4 % of the world's oceans respectively. Averaging over longer timescales would be required in regions with smaller fluxes. Hourly flux detection limits of CH4 from both instruments are generally higher than the expected emissions from the open ocean, though the signal to noise of this measurement may improve closer to the coast.

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Mouat, Asher P., Zelda A. Siegel i Jennifer Kaiser. "Evaluation of Aeris mid-infrared absorption (MIRA), Picarro CRDS (cavity ring-down spectroscopy) G2307, and dinitrophenylhydrazine (DNPH)-based sampling for long-term formaldehyde monitoring efforts". Atmospheric Measurement Techniques 17, nr 7 (8.04.2024): 1979–94. http://dx.doi.org/10.5194/amt-17-1979-2024.

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Abstract. Current formaldehyde (HCHO) measurement networks rely on the TO-11A offline chemical derivatization technique, which can be resource intensive and limited in temporal resolution. In this work, we evaluate the field performance of three new commercial instruments for continuous in situ formaldehyde monitoring: the Picarro cavity ring-down spectroscopy G2307 gas concentration analyzer and Aeris Technologies' mid-infrared absorption Pico and Ultra gas analyzers. All instruments require regular drift correction, which is accomplished through instrument zeroing using dinitrophenylhydrazine (DNPH)-coated cartridges, Drierite, or molecular sieves, while heated Hopcalite failed to remove all incoming HCHO. We show that a modified precision estimate accounting for regular instrument zeroing results in values of 0.09, 0.20, and 0.22 ppb at a 20 min integration time for the G2307, Ultra, and Pico, respectively. After applying standard addition and dynamic dilution calibrations, all instruments agreed within 13 % and were well correlated with each other (all r ≥ 0.90). TO-11A HCHO observations resulted in a normalized mean bias of −58 % compared to co-located Picarro G2307 measurements (r=0.62, slope = 0.38, int = 0.07 ppb HCHO). Using a 6-month deployment period in the Atlanta metropolitan area, we determined that the Picarro G2307 and Aeris units have sufficient accuracy and precision to capture the Atlanta spatial HCHO gradient. We find that midday HCHO concentrations have decreased by 22.3 % since 1999 in the city's urban core, and DNPH measurements at a nearby Photochemical Assessment Monitoring Station (PAMS) site show a greater decrease of 53 %.

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Schneider, M., Y. González, C. Dyroff, E. Christner, A. Wiegele, S. Barthlott, O. E. García i in. "Empirical validation and proof of added value of MUSICA's tropospheric δD remote sensing products". Atmospheric Measurement Techniques Discussions 7, nr 7 (14.07.2014): 6917–69. http://dx.doi.org/10.5194/amtd-7-6917-2014.

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Abstract. The project MUSICA (MUlti-platform remote Sensing of Isotopologues for investigating the Cycle of Atmospheric water) integrates tropospheric water vapour isototopologue remote sensing and in-situ observations. This paper presents a first empirical validation of MUSICA's H2O and δD remote sensing products (generated from ground-based FTIR, Fourier Transform InfraRed, spectrometer and space-based IASI, Infrared Atmospheric Sounding Interferometer, observation). As reference we use well calibrated in-situ measurements made aboard an aircraft (between 200 and 6800 m a.s.l.) by the dedicated ISOWAT instrument and on the island of Tenerife at two different altitudes (at Izaña, 2370 m a.s.l., and at Teide, 3550 m a.s.l.) by two commercial Picarro L2120-i water isotopologue analysers. The comparison to the ISOWAT profile measurements shows that the remote sensors can well capture the variations in the water vapour isotopologues and the scatter with respect to the in-situ references suggests a δD random uncertainty for the FTIR product of much better than 45‰ in the lower troposphere and of about 15‰ for the middle troposphere. For the middle tropospheric IASI δD product the study suggests a respective uncertainty of about 15‰. In addition, we find indications for a positive δD bias in the remote sensing products. The δD data are scientifically interesting only if they add information to the H2O observations. We are able to qualitatively demonstrate the added value of the MUSICA δD remote sensing data by comparing δD-vs.-H2O curves. First, we show that the added value of δD as seen in the Picarro data is similarly seen in FTIR data measured in coincidence. Second, we document that the δD-vs.-H2O curves obtained from the different in-situ and remote sensing data sets (ISOWAT, Picarro at Izaña and Teide, FTIR, and IASI) consistently identify two different moisture transport pathways to the subtropical north eastern Atlantic free troposphere.

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Tian, Shasha, Kexin Zu, Huabin Dong, Limin Zeng, Keding Lu i Qi Chen. "Colorimetric derivatization of ambient ammonia (NH₃) for detection by long-path absorption photometry". Atmospheric Measurement Techniques 16, nr 22 (18.11.2023): 5525–35. http://dx.doi.org/10.5194/amt-16-5525-2023.

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Abstract. In the last few decades, various techniques, including spectroscopic, mass spectrometric, chemiluminescence and wet chemical methods, have been developed and applied for the detection of gaseous ammonia (NH3). We developed an online NH3 monitoring system – salicylic acid derivatization reaction and long-path absorption photometer (SAC-LOPAP) – based on a selective colorimetric reaction to form a highly absorbing reaction product and a LOPAP, which could run stably for a long time and be applied to the continuous online measurement of low concentrations of ambient NH3 by optimizing the reaction conditions, adding a constant-temperature module and liquid flow controller. The detection limit reached with this instrument was 40.5 parts per trillion (ppt) with a stripping liquid flow rate of 0.49 mL min−1 and a gas sample flow rate of 0.70 L min−1. An inter-comparison of our system with a commercial Picarro G2103 analyzer (Picarro, USA) in Beijing was presented, and the results showed that the two instruments had a good correlation with a slope of 1.00 and an R2 of 0.96, indicating that the SAC-LOPAP instrument involved in this study could be used for the accurate measurement of NH3.

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Nemuc, Anca, Andreea Boscornea, Livio Belegante, Jeni Vasilescu, Sorin Vajaiac, Dragos Ene, Luminita Marmureanu i Simona Andrei. "Ground based and airborne atmospheric measurements near bucharest". EPJ Web of Conferences 176 (2018): 08009. http://dx.doi.org/10.1051/epjconf/201817608009.

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This paper presents the results from a coordinated approach for atmospheric investigation, exploring synergies between different techniques. A wide range of instruments have been used during an intensive measurement period both from ground (lidar, sunphotometer, aethalometer and Aerosol Chemical Speciation Monitor) and airborne (aerodynamic particle sizer, the Picarro gas analyzer and the NO2 CAPS analyzer) in 2016 over Magurele, 6 km South West of Bucharest.

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Zhuang, Shaojie, Eva Brusselman, Bart Sonck i Peter Demeyer. "Validation of Five Gas Analysers for Application in Ammonia Emission Measurements at Livestock Houses According to the VERA Test Protocol". Applied Sciences 10, nr 15 (22.07.2020): 5034. http://dx.doi.org/10.3390/app10155034.

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Ammonia emissions are an important issue in livestock production. Many mitigation measures have been proposed in order to reduce the environmental impact of livestock farms, and reliable field measurements are required to evaluate the amount of released or reduced ammonia while applying these measures. Following the guideline of the Verification of Environmental Technologies for Agricultural Production test protocol, five commercially available gas analysers, i.e., INNOVA 1314, Picarro G2103, Rosemount CT5100, Gasmet CX4000, and Axetris LGD F200-A, were validated as alternative methods to the wet-chemistry method (reference method) for measuring ammonia in livestock houses. High correlations ( r > 0.99 ) were found between the analysers and the reference method. The measurement errors of the tested analysers were below 2 ppmv or 10%. Equivalence to the wet-chemistry method was demonstrated for the INNOVA and Rosemount analysers without a recalibration and for the Picarro and Axetris analysers with a recalibration. The Gasmet analyser was seemingly subjected to an interference from carbon-dioxide and, after compensating for the cross-sensitivity, the equivalence to the wet-chemistry method could also be demonstrated. Calibration curves that were based on a certified gas cylinder were inconsistent with that based on wet-chemistry measurements, which suggested that field calibration might be necessary for optimal measurement accuracy.

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Tsai, Tracy R., Kendrick Du i Bill Stavropoulos. "New system for detecting, mapping, monitoring, quantifying and reporting fugitive gas emissions". APPEA Journal 57, nr 2 (2017): 561. http://dx.doi.org/10.1071/aj16098.

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Coal seam gas (CSG) is an abundant energy source that’s been portrayed as having a lower Greenhouse Gas footprint than coal, but there have been concerns that fugitive emissions may be larger than estimated. Fugitive emissions associated with CSG development are engineered release points (valves and vents etc.) and unintentional equipment leaks. Various gas detection technologies are utilised across the industry that are effective at detecting large emissions sources in close proximity, but they are difficult to scale up to the large size needed for the CSG industry. We’ll present a summary of a trial utilising a new mobile methane detection and emission quantification system: the Picarro EQ (Emissions Quantification). After driving this instrument around CSG infrastructure, Picarro’s cloud-based analytics generate a map of methane measurements and emissions with wind indicators pointing to likely sources. Since all measurements are on a secure cloud-based service, any authorised operator can log into it to run reports and analytics. This system has been used to make measurements in the Barnett Shale, United States. We present results and demonstrate its usage within an operational CSG area to quantify and identify emissions from CSG infrastructure.

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Dickinson, Dane, Samuel Bodé i Pascal Boeckx. "System for δ13C–CO2 and xCO2 analysis of discrete gas samples by cavity ring-down spectroscopy". Atmospheric Measurement Techniques 10, nr 11 (22.11.2017): 4507–19. http://dx.doi.org/10.5194/amt-10-4507-2017.

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Abstract. A method was devised for analysing small discrete gas samples (50 mL syringe) by cavity ring-down spectroscopy (CRDS). Measurements were accomplished by inletting 50 mL syringed samples into an isotopic-CO2 CRDS analyser (Picarro G2131-i) between baseline readings of a reference air standard, which produced sharp peaks in the CRDS data feed. A custom software script was developed to manage the measurement process and aggregate sample data in real time. The method was successfully tested with CO2 mole fractions (xCO2) ranging from < 0.1 to > 20 000 ppm and δ13C–CO2 values from −100 up to +30 000 ‰ in comparison to VPDB (Vienna Pee Dee Belemnite). Throughput was typically 10 samples h−1, with 13 h−1 possible under ideal conditions. The measurement failure rate in routine use was ca. 1 %. Calibration to correct for memory effects was performed with gravimetric gas standards ranging from 0.05 to 2109 ppm xCO2 and δ13C–CO2 levels varying from −27.3 to +21 740 ‰. Repeatability tests demonstrated that method precision for 50 mL samples was ca. 0.05 % in xCO2 and 0.15 ‰ in δ13C–CO2 for CO2 compositions from 300 to 2000 ppm with natural abundance 13C. Long-term method consistency was tested over a 9-month period, with results showing no systematic measurement drift over time. Standardised analysis of discrete gas samples expands the scope of application for isotopic-CO2 CRDS and enhances its potential for replacing conventional isotope ratio measurement techniques. Our method involves minimal set-up costs and can be readily implemented in Picarro G2131-i and G2201-i analysers or tailored for use with other CRDS instruments and trace gases.

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Cai, Qixiang, Pengfei Han, Guang Pan, Chi Xu, Xiaoyu Yang, Honghui Xu, Dongde Ruan i Ning Zeng. "Evaluation of Low-Cost CO2 Sensors Using Reference Instruments and Standard Gases for Indoor Use". Sensors 24, nr 9 (23.04.2024): 2680. http://dx.doi.org/10.3390/s24092680.

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CO2 monitoring is important for carbon emission evaluation. Low-cost and medium-precision sensors (LCSs) have become an exploratory direction for CO2 observation under complex emission conditions in cities. Here, we used a calibration method that improved the accuracy of SenseAir K30 CO2 sensors from ±30 ppm to 0.7–4.0 ppm for a CO2-monitoring instrument named the SENSE-IAP, which has been used in several cities, such as in Beijing, Jinan, Fuzhou, Hangzhou, and Wuhan, in China since 2017. We conducted monthly to yearly synchronous observations using the SENSE-IAP along with reference instruments (Picarro) and standard gas to evaluate the performance of the LCSs for indoor use with relatively stable environments. The results show that the precision and accuracy of the SENSE-IAP compared to the standard gases were rather good in relatively stable indoor environments, with the short-term (daily scale) biases ranging from −0.9 to 0.2 ppm, the root mean square errors (RMSE) ranging from 0.7 to 1.6 ppm, the long-term (monthly scale) bias ranging from −1.6 to 0.5 ppm, and the RMSE ranging from 1.3 to 3.2 ppm. The accuracy of the synchronous observations with Picarro was in the same magnitude, with an RMSE of 2.0–3.0 ppm. According to our evaluation, standard instruments or reliable standard gases can be used as a reference to improve the accuracy of the SENSE-IAP. If calibrated daily using standard gases, the bias of the SENSE-IAP can be maintained within 1.0 ppm. If the standard gases are hard to access frequently, we recommend a calibration frequency of at least three months to maintain an accuracy within 3 ppm.

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Schneider, M., Y. González, C. Dyroff, E. Christner, A. Wiegele, S. Barthlott, O. E. García i in. "Empirical validation and proof of added value of MUSICA's tropospheric δD remote sensing products". Atmospheric Measurement Techniques 8, nr 1 (30.01.2015): 483–503. http://dx.doi.org/10.5194/amt-8-483-2015.

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Abstract. The project MUSICA (MUlti-platform remote Sensing of Isotopologues for investigating the Cycle of Atmospheric water) integrates tropospheric water vapour isotopologue remote sensing and in situ observations. This paper presents a first empirical validation of MUSICA's H2O and δD remote sensing products, generated from ground-based FTIR (Fourier transform infrared), spectrometer and space-based IASI (infrared atmospheric sounding interferometer) observation. The study is made in the area of the Canary Islands in the subtropical northern Atlantic. As reference we use well calibrated in situ measurements made aboard an aircraft (between 200 and 6800 m a.s.l.) by the dedicated ISOWAT instrument and on the island of Tenerife at two different altitudes (at Izaña, 2370 m a.s.l., and at Teide, 3550 m a.s.l.) by two commercial Picarro L2120-i water isotopologue analysers. The comparison to the ISOWAT profile measurements shows that the remote sensors can well capture the variations in the water vapour isotopologues, and the scatter with respect to the in situ references suggests a δD random uncertainty for the FTIR product of much better than 45‰ in the lower troposphere and of about 15‰ for the middle troposphere. For the middle tropospheric IASI δD product the study suggests a respective uncertainty of about 15‰. In both remote sensing data sets we find a positive δD bias of 30–70‰. Complementing H2O observations with δD data allows moisture transport studies that are not possible with H2O observations alone. We are able to qualitatively demonstrate the added value of the MUSICA δD remote sensing data. We document that the δD–H2O curves obtained from the different in situ and remote sensing data sets (ISOWAT, Picarro at Izaña and Teide, FTIR, and IASI) consistently identify two different moisture transport pathways to the subtropical north eastern Atlantic free troposphere.

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Zhang, Haiwei, Christoph Spötl, Ye Tian, Youfeng Ning, Baoyun Zong, Yuri V. Dublyansky, Pengzhen Duan, Hai Cheng, Yanjun Cai i Hubert B. Vonhof. "Measurement of oxygen and hydrogen isotopic ratios of speleothem fluid inclusion water using Picarro". Chinese Science Bulletin 65, nr 32 (3.08.2020): 3626–34. http://dx.doi.org/10.1360/tb-2020-0201.

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Reum, Friedemann, Christoph Gerbig, Jost V. Lavric, Chris W. Rella i Mathias Göckede. "Correcting atmospheric CO2 and CH4 mole fractions obtained with Picarro analyzers for sensitivity of cavity pressure to water vapor". Atmospheric Measurement Techniques 12, nr 2 (15.02.2019): 1013–27. http://dx.doi.org/10.5194/amt-12-1013-2019.

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Abstract. Measurements of dry air mole fractions of atmospheric greenhouse gases are used in inverse models of atmospheric tracer transport to quantify their sources and sinks. The measurements have to be calibrated to a common scale to avoid bias in the inferred fluxes. For this purpose, the World Meteorological Organization (WMO) has set requirements for the interlaboratory compatibility of atmospheric greenhouse gas (GHG) measurements. A widely used series of devices for these measurements are the GHG analyzers manufactured by Picarro, Inc. These are often operated in humid air, and the effects of water vapor are corrected for in post-processing. Here, we report on rarely detected and previously unexplained biases of the water correction method for CO2 and CH4 in the literature. They are largest at water vapor mole fractions below 0.5 % H2O, which were undersampled in previous studies, and can therefore affect measurements obtained in humid air. Setups that dry sample air using Nafion membranes may be affected as well if there are differences in residual water vapor levels between sample and calibration air. The biases are caused by a sensitivity of the pressure in the measurement cavity to water vapor. We correct these biases by modifying the water correction method from the literature. Our method relies on experiments that maintain stable water vapor levels to allow equilibration of cavity pressure. In our experiments with the commonly used droplet method, this requirement was not fulfilled. Correcting CO2 measurements proved challenging, presumably because of our humidification method. Open questions pertain to differences among analyzers and variability over time. In our experiments, the biases amounted to considerable fractions of the WMO interlaboratory compatibility goals. Since measurements of dry air mole fractions of CO2 and CH4 are also subject to other uncertainties, correcting the cavity pressure-related biases helps keep the overall accuracy of measurements obtained with Picarro GHG analyzers in humid and potentially in Nafion-dried air within the WMO goals.

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Defratyka, Sara M., Jean-Daniel Paris, Camille Yver-Kwok, Daniel Loeb, James France, Jon Helmore, Nigel Yarrow, Valérie Gros i Philippe Bousquet. "Ethane measurement by Picarro CRDS G2201-i in laboratory and field conditions: potential and limitations". Atmospheric Measurement Techniques 14, nr 7 (27.07.2021): 5049–69. http://dx.doi.org/10.5194/amt-14-5049-2021.

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Abstract. Atmospheric ethane can be used as a tracer to distinguish methane sources, both at the local and global scale. Currently, ethane can be measured in the field using flasks or in situ analyzers. In our study, we characterized the CRDS Picarro G2201-i instrument, originally designed to measure isotopic CH4 and CO2, for measurements of ethane-to-methane ratio in mobile-measurement scenarios, near sources and under field conditions. We evaluated the limitations and potential of using the CRDS G2201-i to measure the ethane-to-methane ratio, thus extending the instrument application to simultaneously measure two methane source proxies in the field: carbon isotopic ratio and the ethane-to-methane ratio. First, laboratory tests were run to characterize the instrument in stationary conditions. Subsequently, the instrument performance was tested in field conditions as part of a controlled release experiment. Finally, the instrument was tested during mobile measurements focused on gas compressor stations. The results from the field were afterwards compared with the results obtained from instruments specifically designed for ethane measurements. Our study shows the potential of using the CRDS G2201-i instrument in a mobile configuration to determine the ethane-to-methane ratio in methane plumes under measurement conditions with an ethane uncertainty of 50 ppb. Assuming typical ethane-to-methane ratios ranging between 0 and 0.1 ppb ppb−1, we conclude that the instrument can accurately estimate the “true” ethane-to-methane ratio within 1σ uncertainty when CH4 enhancements are at least 1 ppm, as can be found in the vicinity of strongly emitting sites such as natural gas compressor stations and roadside gas pipeline leaks.

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Grodowski, Jarosław. "Optymalizacja planowania wymiany sieci dystrybucyjnej i metody kwantyfikacji emisji gazu ziemnego z zastosowaniem metodologii PICARRO". GAZ, WODA I TECHNIKA SANITARNA 1, nr 4 (26.04.2023): 13–20. http://dx.doi.org/10.15199/17.2023.4.2.

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Hutchings, Jack A., i Bronwen L. Konecky. "Optimization of a Picarro L2140-i cavity ring-down spectrometer for routine measurement of triple oxygen isotope ratios in meteoric waters". Atmospheric Measurement Techniques 16, nr 6 (29.03.2023): 1663–82. http://dx.doi.org/10.5194/amt-16-1663-2023.

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Abstract. The demanding precision of triple oxygen isotope (Δ17O) analyses in water has restricted their measurement to dual-inlet mass spectrometry until the recent development of commercially available infrared laser analyzers. Laser-based measurements of triple oxygen isotope ratios are now increasingly performed by laboratories seeking to better constrain the source and history of meteoric waters. However, in practice, these measurements are subject to large analytical errors that remain poorly documented in scientific literature and by instrument manufacturers, which can effectively restrict the confident application of Δ17O to settings where variations are relatively large (∼ 25–60 per meg). We present our operating method of a Picarro L2140-i cavity ring-down spectrometer (CRDS) during the analysis of low-latitude rainwater where confidently resolving daily variations in Δ17O (differences of ∼ 10–20 per meg) was desired. Our approach was optimized over ∼ 3 years and uses a combination of published best practices plus additional steps to combat spectral contamination of trace amounts of dissolved organics, which, for Δ17O, emerges as a much more substantial problem than previously documented, even in pure rainwater. We resolve the extreme sensitivity of the Δ17O measurement to organics through their removal via Picarro's micro-combustion module, whose performance is evaluated in each sequence using alcohol-spiked standards. While correction for sample-to-sample memory and instrumental drift significantly improves traditional isotope metrics, these corrections have only a marginal impact (0–1 per meg error reduction) on Δ17O. Our post-processing scheme uses the analyzer's high-resolution data, which improves δ2H measurement (0.25 ‰ error reduction) and allows for much more rich troubleshooting and data processing compared to the default user-facing data output. In addition to competitive performance for traditional isotope metrics, we report a long-term, control standard root mean square error for Δ17O of 12 per meg. Overall performance (Δ17O error of 6 per meg, calculated by averaging three replicates spread across distinct, independently calibrated sequences) is comparable to mass spectrometry and requires only ∼ 6.3 h per sample. We demonstrate the impact of our approach using a rainfall dataset from Uganda and offer recommendations for other efforts that aim to measure meteoric Δ17O via CRDS.

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Courtois, Elodie Alice, Clément Stahl, Benoit Burban, Joke Van den Berge, Daniel Berveiller, Laëtitia Bréchet, Jennifer Larned Soong, Nicola Arriga, Josep Peñuelas i Ivan August Janssens. "Automatic high-frequency measurements of full soil greenhouse gas fluxes in a tropical forest". Biogeosciences 16, nr 3 (12.02.2019): 785–96. http://dx.doi.org/10.5194/bg-16-785-2019.

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Abstract. Measuring in situ soil fluxes of carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) continuously at high frequency requires appropriate technology. We tested the combination of a commercial automated soil CO2 flux chamber system (LI-8100A) with a CH4 and N2O analyzer (Picarro G2308) in a tropical rainforest for 4 months. A chamber closure time of 2 min was sufficient for a reliable estimation of CO2 and CH4 fluxes (100 % and 98.5 % of fluxes were above minimum detectable flux – MDF, respectively). This closure time was generally not suitable for a reliable estimation of the low N2O fluxes in this ecosystem but was sufficient for detecting rare major peak events. A closure time of 25 min was more appropriate for reliable estimation of most N2O fluxes (85.6 % of measured fluxes are above MDF ± 0.002 nmol m−2 s−1). Our study highlights the importance of adjusted closure time for each gas.

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Долгих, Г. И., М. А. Бовсун, С. Г. Долгих, В. А. Чупин i А. В. Яцук. "Аппаратно-программный комплекс для исследования мелкомасштабных вариаций парниковых газов". PHOTONICS Russia 17, nr 4 (28.06.2023): 294–306. http://dx.doi.org/10.22184/1993-7296.fros.2023.17.4.294.306.

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Для изучения природы вариаций парниковых газов создан аппаратно-программный комплекс, состоящий из 52,5‑метрового лазерного деформографа, 17,5‑метрового лазерного деформографа, лазерного нанобарографа и мобильной лаборатории НИС «Профессор Гагаринский», состоящей из атмохимического измерительного комплекса (газоанализатор Picarro), комплекса метеорологических приборов на верхней палубе мостика, судовой газоаналитической лаборатории и проточной судовой системы. При обработке экспериментальных данных по вариациям деформаций верхнего слоя земной коры и вариациям атмосферного давления на м. Шульца, а также при анализе вариаций метана, углекислого газа и паров воды в приводной атмосфере на шельфе Японского моря на удалении около 2 км от м. Шульца установлены общие закономерности в поведении изучаемых параметров верхнего слоя земной коры и приводного слоя атмосферы в инфрагравитационном диапазоне. Выделены общие мощные колебания с периодами от 7 мин 59,1 с до 7 мин 45,5 с, 28 мин 28,8 с, от 30 мин 07,6 с до 31 мин 59,1, с первоисточник которых может быть связан как с атмосферными процессами, так и с основным (радиальным) тоном собственных колебаний Земли 0S0.

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Tolodo, D. D., I. N. Manyoe i Y. I. Arifin. "Geochemistry characteristics of the hungayono geothermal area for the development of clean energy in gorontalo province". IOP Conference Series: Earth and Environmental Science 1089, nr 1 (1.11.2022): 012020. http://dx.doi.org/10.1088/1755-1315/1089/1/012020.

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Abstract Geothermal energy has great potential to provide clean energy so that the Sustainable Development Goals (SDGs) can be achieved. The purpose of this study was to identify the geochemical characteristics of the geothermal fluid in the Hungayono area. Geothermal fluid sampling is performed at two points of manifestation which have the highest temperature. The cation and anion testing of geothermal fluid using Atomic Absorption Spectrophotometer (AAS) and isotope testing using the Picarro Water Isotope Analyzer. Data analysis using Giggenbach diagrams. Hot spring temperatures are 54 - 60°C. The deposits at the point of manifestation are iron oxide with neutral fluid pH. Based on the results of the analysis of cations, anions, and isotopes, the Hungayono geothermal fluid is a type of chloride fluid that has been mixed with meteoric water. Based on the geothermometer calculation, reservoir temperature is 232-234°C. Hungayono Geothermal is a type of system with moderate to high concentration.

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Peltola, O., A. Hensen, C. Helfter, L. Belelli Marchesini, F. C. Bosveld, W. C. M. van den Bulk, J. A. Elbers i in. "Evaluating the performance of commonly used gas analysers for methane eddy covariance flux measurements: the InGOS inter-comparison field experiment". Biogeosciences 11, nr 12 (17.06.2014): 3163–86. http://dx.doi.org/10.5194/bg-11-3163-2014.

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Abstract. The performance of eight fast-response methane (CH4) gas analysers suitable for eddy covariance flux measurements were tested at a grassland site near the Cabauw tall tower (Netherlands) during June 2012. The instruments were positioned close to each other in order to minimise the effect of varying turbulent conditions. The moderate CH4 fluxes observed at the location, of the order of 25 nmol m−2 s−1, provided a suitable signal for testing the instruments' performance. Generally, all analysers tested were able to quantify the concentration fluctuations at the frequency range relevant for turbulent exchange and were able to deliver high-quality data. The tested cavity ringdown spectrometer (CRDS) instruments from Picarro, models G2311-f and G1301-f, were superior to other CH4 analysers with respect to instrumental noise. As an open-path instrument susceptible to the effects of rain, the LI-COR LI-7700 achieved lower data coverage and also required larger density corrections; however, the system is especially useful for remote sites that are restricted in power availability. In this study the open-path LI-7700 results were compromised due to a data acquisition problem in our data-logging setup. Some of the older closed-path analysers tested do not measure H2O concentrations alongside CH4 (i.e. FMA1 and DLT-100 by Los Gatos Research) and this complicates data processing since the required corrections for dilution and spectroscopic interactions have to be based on external information. To overcome this issue, we used H2O mole fractions measured by other gas analysers, adjusted them with different methods and then applied them to correct the CH4 fluxes. Following this procedure we estimated a bias of the order of 0.1 g (CH4) m−2 (8% of the measured mean flux) in the processed and corrected CH4 fluxes on a monthly scale due to missing H2O concentration measurements. Finally, cumulative CH4 fluxes over 14 days from three closed-path gas analysers, G2311-f (Picarro Inc.), FGGA (Los Gatos Research) and FMA2 (Los Gatos Research), which were measuring H2O concentrations in addition to CH4, agreed within 3% (355–367 mg (CH4) m−2) and were not clearly different from each other, whereas the other instruments derived total fluxes which showed small but distinct differences (±10%, 330–399 mg (CH4) m−2).

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Peltola, O., A. Hensen, C. Helfter, L. Belelli Marchesini, F. C. Bosveld, W. C. M. van den Bulk, J. A. Elbers i in. "Evaluating the performance of commonly used gas analysers for methane eddy covariance flux measurements: the InGOS inter-comparison field experiment". Biogeosciences Discussions 11, nr 1 (13.01.2014): 797–852. http://dx.doi.org/10.5194/bgd-11-797-2014.

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Abstract. The performance of eight fast-response methane (CH4) gas analysers suitable for eddy covariance flux measurements were tested at a grassland site near the Cabauw tall tower (Netherlands) during June 2012. The instruments were positioned close to each other in order to minimize the effect of varying turbulent conditions. The moderate CH4 fluxes observed at the location, of the order of 25 nmol m−2 s−1, provided a suitable signal for testing the instruments' performance. Generally, all analysers tested were able to quantify the concentration fluctuations at the frequency range relevant for turbulent exchange and were able to deliver high-quality data. The tested cavity ring-down spectrometer (CRDS) instruments from Picarro, models G2311-f and G1301-f, were superior to other CH4 analysers with respect to instrumental noise. As an open-path instrument susceptible to the effects of rain, the LI-COR LI-7700 achieved lower data coverage and also required larger density corrections; however, the system is especially useful for remote sites that are restricted in power availability. In this study the open-path LI-7700 results were compromised due to a data acquisition problem in our data-logging setup. Some of the older closed-path analysers tested do not measure H2O vapour concentrations alongside CH4 (i.e. FMA1 and DLT-100 by Los Gatos Research) and this complicates data processing since the required corrections for dilution and spectroscopic interactions have to be based on external information. To overcome this issue, we used H2O mole fractions measured by other gas analysers, adjusted them with different methods and then applied them to correct the CH4 fluxes. Following this procedure we estimated a bias on the order of 0.1 g (CH4) m−2 (8% of the measured mean flux) in the processed and corrected CH4 fluxes on a monthly scale due to missing H2O concentration measurements. Finally, cumulative CH4 fluxes over 14 days from three closed-path gas analysers, G2311-f (Picarro Inc.), FGGA (Los Gatos Research) and FMA2 (Los Gatos Research), which were measuring H2O vapour concentrations in addition to CH4, agreed within 3% (355–367 mg (CH4) m−2) and were not clearly different from each other, whereas the other instruments derived total fluxes which showed small but distinct differences (±10%, 330–399 mg (CH4) m−2).

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YURKOV, I. A., S. K. DZHOLUMBETOV i E. A. GULYAEV. "ESTIMATION OF NOCTURNAL GREENHOUSE GAS EMISSIONS IN YEKATERINBURG IN 2018-2019". Meteorologiya i Gidrologiya, nr 11 (listopad 2021): 64–72. http://dx.doi.org/10.52002/0130-2906-2021-11-64-72.

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Surface fluxes of carbon gases in Yekaterinburg during 2018-2019 are estimated, their values are 82.77 ± 28.31, 6120 ± 2132, 17.97 ± 6.6 t/(km2 year) for СО, СО2, and СН4, respectively. Continuous measurements of concentrations in the atmospheric surface layer were conducted at the Institute of Industrial Ecology (Ural Branch, Russian Academy of Sciences) in Yekaterinburg using the Picarro G2401 gas analyzer. The regions with increasing nocturnal concentrations of carbon gases in calm conditions were detected during the surface fluxes estimation: wind speed was 0-1 m/s. Further calculation of surface fluxes for the selected time intervals was based on the measured concentrations and some meteorological parameters (the height of the atmospheric boundary layer, temperature, etc.). The results of the present study are comparable with the results of the studies that used a similar method. A surface fluxes growth is observed as the population size increases, while a dependence on the population density is not revealed. The largest contribution to the total uncertainty is made by the height of the atmospheric boundary layer.

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Xiang, B., D. D. Nelson, J. B. McManus, M. S. Zahniser, R. Wehr i S. C. Wofsy. "Development and field testing of a rapid and ultra-stable atmospheric carbon dioxide spectrometer". Atmospheric Measurement Techniques Discussions 7, nr 8 (5.08.2014): 8101–23. http://dx.doi.org/10.5194/amtd-7-8101-2014.

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Abstract. We present field test results for a new spectroscopic instrument to measure atmospheric carbon dioxide (CO2) with high precision (0.02 ppm at 1 Hz) and demonstrate high stability (within 0.1 ppm over more than 8 months), without the need for hourly, daily, or even monthly calibration against high-pressure gas cylinders. The technical novelty of this instrument (ABsolute Carbon dioxide, ABC) is the spectral null method using an internal quartz reference cell with known CO2 column density. Compared to a previously described prototype, the field instrument has better stability and benefits from more precise thermal control of the optics and more accurate pressure measurements in the sample cell (at the mTorr level). The instrument has been deployed at a long-term ecological research site (the Harvard Forest, USA), where it has measured for eight months without on-site calibration and with minimal maintenance, showing drift bounds of less than 0.1 ppm. Field measurements agree well with those of another commercially available cavity ring-down CO2 instrument (Picarro G2301) run with a standard calibration protocol. This field test demonstrates that ABC is capable of performing high-accuracy, unattended, continuous field measurements with minimal use of calibration cylinders.

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Aichner, Bernhard, David Dubbert, Christine Kiel, Katrin Kohnert, Igor Ogashawara, Andreas Jechow, Sarah-Faye Harpenslager i in. "Spatial and seasonal patterns of water isotopes in northeastern German lakes". Earth System Science Data 14, nr 4 (19.04.2022): 1857–67. http://dx.doi.org/10.5194/essd-14-1857-2022.

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Abstract. Water stable isotopes (δ18O and δ2H) were analyzed in samples collected in lakes, associated with riverine systems in northeastern Germany, throughout 2020. The dataset (Aichner et al., 2021; https://doi.org/10.1594/PANGAEA.935633) is derived from water samples collected at (a) lake shores (sampled in March and July 2020), (b) buoys which were temporarily installed in deep parts of the lake (sampled monthly from March to October 2020), (c) multiple spatially distributed spots in four selected lakes (in September 2020), and (d) the outflow of Müggelsee (sampled biweekly from March 2020 to January 2021). At shores, water was sampled with a pipette from 40–60 cm below the water surface and directly transferred into a measurement vial, while at buoys a Limnos water sampler was used to obtain samples from 1 m below the surface. Isotope analysis was conducted at IGB Berlin, using a Picarro L2130-i cavity ring-down spectrometer, with a measurement uncertainty of <0.15 ‰ (δ18O) and <0.0 ‰ (δ2H). The data give information about the vegetation period and the full seasonal isotope amplitude in the sampled lakes and about spatial isotope variability in different branches of the associated riverine systems.

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Panov, Alexey, Anatoly Prokushkin, Karl Robert Kübler, Mikhail Korets, Anastasiya Urban, Mikhail Bondar i Martin Heimann. "Continuous CO2 and CH4 Observations in the Coastal Arctic Atmosphere of the Western Taimyr Peninsula, Siberia: The First Results from a New Measurement Station in Dikson". Atmosphere 12, nr 7 (6.07.2021): 876. http://dx.doi.org/10.3390/atmos12070876.

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Atmospheric observations of sources and sinks of carbon dioxide (CO2) and methane (CH4) in the pan-Arctic domain are highly sporadic, limiting our understanding of carbon turnover in this climatically sensitive environment and the fate of enormous carbon reservoirs buried in permafrost. Particular gaps apply to the Arctic latitudes of Siberia, covered by the vast tundra ecosystems underlain by permafrost, where only few atmospheric sites are available. The paper presents the first results of continuous observations of atmospheric CO2 and CH4 dry mole fractions at a newly operated station “DIAMIS” (73.506828° N, 80.519869° E) deployed on the edge of the Dikson settlement on the western coast of the Taimyr Peninsula. Atmospheric mole fractions of CO2, CH4, and H2O are measured by a CRDS analyzer Picarro G2301-f, which is regularly calibrated against WMO-traceable gases. Meteorological records permit screening of trace gas series. Here, we give the scientific rationale of the site, describe the instrumental setup, analyze the local environments, examine the seasonal footprint, and show CO2 and CH4 fluctuations for the daytime mixed atmospheric layer that is representative over a vast Arctic domain (~500–1000 km), capturing both terrestrial and oceanic signals.

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Hita, Luis González, Miguel Angel Mejía-González, Blanca Carteño Martinez, Juan Carlos Aparicio-González i Dustin Mañón Flores. "Isotopic composition of rainfall in Baja California Sur, México". International Journal of Hydrology 5, nr 3 (1.06.2021): 93–100. http://dx.doi.org/10.15406/ijh.2021.05.00271.

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The study of the connection between precipitation and groundwater recharge/discharge using stable isotopes has been limited in México. One of the main limitations is the lack of local stable isotopes monitoring for rainfall. Indeed, only two stations of the Global Network of Isotopes in Precipitation operated in Mexico from 1962 to 1988. This study reports temporal characterization of stable isotopes in meteoric waters in the northwest of Mexico that has been lacking up to the present. Stable isotope analyses of the rain collected in the city of Loreto, state of Baja California Sur, from 2018 to 2021 were conducted using laser water isotope analyzers Picarro L2110-i and Los Gatos Research LWIA-45EP. A least squares regression of the isotope data was used to obtain the local meteoric water line: δ2H =8 δ18O + 9.4 (r2=0.98). The average value of winter rain is δ18O=-2.46 ‰ and δ2H=-10.2 ‰, monsoon rain δ18O=-4.93 ‰ y δ2H=-30.3 ‰, atmospheric river rain δ18O=-5.35 ‰ and δ2H=-33.3 ‰ and tropical cyclones rain δ18O= -10.7 ‰ y δ2H=-76.3. Isotope data indicated that tropical cyclones are the main source of recharge for the coastal aquifers of Baja California, Sur.

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Gribanov, K., J. Jouzel, V. Bastrikov, J. L. Bonne, F. M. Breon, M. Butzin, O. Cattani i in. "Developing a western Siberia reference site for tropospheric water vapour isotopologue observations obtained by different techniques (in situ and remote sensing)". Atmospheric Chemistry and Physics 14, nr 12 (16.06.2014): 5943–57. http://dx.doi.org/10.5194/acp-14-5943-2014.

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Abstract. Water stable isotopologues provide integrated tracers of the atmospheric water cycle, affected by changes in air mass origin, non-convective and convective processes and continental recycling. Novel remote sensing and in situ measuring techniques have recently offered opportunities for monitoring atmospheric water vapour isotopic composition. Recently developed infrared laser spectrometers allow for continuous in situ measurements of surface water vapour δDv and δ18Ov. So far, very few intercomparisons of measurements conducted using different techniques have been achieved at a given location, due to difficulties intrinsic to the comparison of integrated with local measurements. Nudged simulations conducted with high-resolution isotopically enabled general circulation models (GCMs) provide a consistent framework for comparison with the different types of observations. Here, we compare simulations conducted with the ECHAM5-wiso model with two types of water vapour isotopic data obtained during summer 2012 at the forest site of Kourovka, western Siberia: hourly ground-based FTIR total atmospheric columnar δDv amounts, and in situ hourly Picarro δDv measurements. There is an excellent correlation between observed and predicted δDv at surface while the comparison between water column values derived from the model compares well with FTIR estimates.

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Fleming, Leigh S., Andrew C. Manning, Penelope A. Pickers, Grant L. Forster i Alex J. Etchells. "Evaluating the performance of a Picarro G2207-i analyser for high-precision atmospheric O₂ measurements". Atmospheric Measurement Techniques 16, nr 2 (24.01.2023): 387–401. http://dx.doi.org/10.5194/amt-16-387-2023.

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Abstract. Fluxes of oxygen (O2) and carbon dioxide (CO2) in and out of the atmosphere are strongly coupled for terrestrial biospheric exchange processes and fossil fuel combustion but are uncoupled for oceanic air–sea gas exchange. High-precision measurements of both species can therefore provide constraints on the carbon cycle and can be used to quantify fossil fuel CO2 (ffCO2) emission estimates. In the case of O2, however, due to its large atmospheric mole fraction (∼20.9 %) it is very challenging to measure small variations to the degree of precision and accuracy required for these applications. We have tested an atmospheric O2 analyser based on the principle of cavity ring-down spectroscopy (Picarro Inc., model G2207-i), both in the laboratory and at the Weybourne Atmospheric Observatory (WAO) field station in the UK, in comparison to well-established, pre-existing atmospheric O2 and CO2 measurement systems. In laboratory tests analysing dry air in high-pressure cylinders, we found that the best precision was achieved with 30 min averaging and was ±0.5 ppm (∼±2.4 per meg). Also from continuous measurements from a cylinder of dry air, we found the 24 h peak-to-peak range of hourly averaged values to be 1.2 ppm (∼5.8 per meg). These results are close to atmospheric O2 compatibility goals as set by the UN World Meteorological Organization. However, from measurements of ambient air conducted at WAO we found that the built-in water correction of the G2207-i does not sufficiently correct for the influence of water vapour on the O2 mole fraction. When sample air was dried and a 5-hourly baseline correction with a reference gas cylinder was employed, the G2207-i's results showed an average difference from the established O2 analyser of 13.6±7.5 per meg (over 2 weeks of continuous measurements). Over the same period, based on measurements of a so-called “target tank”, analysed for 12 min every 7 h, we calculated a repeatability of ±5.7±5.6 per meg and a compatibility of ±10.0±6.7 per meg for the G2207-i. To further examine the G2207-i's performance in real-world applications we used ambient air measurements of O2 together with concurrent CO2 measurements to calculate ffCO2. Due to the imprecision of the G2207-i, the ffCO2 calculated showed large differences from that calculated from the established measurement system and had a large uncertainty of ±13.0 ppm, which was roughly double that from the established system (±5.8 ppm).

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Xiang, B., D. D. Nelson, J. B. McManus, M. S. Zahniser, R. A. Wehr i S. C. Wofsy. "Development and field testing of a rapid and ultra-stable atmospheric carbon dioxide spectrometer". Atmospheric Measurement Techniques 7, nr 12 (15.12.2014): 4445–53. http://dx.doi.org/10.5194/amt-7-4445-2014.

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Abstract. We present field test results for a new spectroscopic instrument to measure atmospheric carbon dioxide (CO2) with high precision (0.02 μmol mol−1, or ppm at 1 Hz) and demonstrate high stability (within 0.1 ppm over more than 8 months), without the need for hourly, daily, or even monthly calibration against high-pressure gas cylinders. The technical novelty of this instrument (ABsolute Carbon dioxide, ABC) is the spectral null method using an internal quartz reference cell with known CO2 column density. Compared to a previously described prototype, the field instrument has better stability and benefits from more precise thermal control of the optics and more accurate pressure measurements in the sample cell (at the mTorr level). The instrument has been deployed at a long-term ecological research site (the Harvard Forest, USA), where it has measured for 8 months without on-site calibration and with minimal maintenance, showing drift bounds of less than 0.1 ppm. Field measurements agree well with those of a commercially available cavity ring-down CO2 instrument (Picarro G2301) run with a standard calibration protocol. This field test demonstrates that ABC is capable of performing high-accuracy, unattended, continuous field measurements with minimal use of reference gas cylinders.

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Papina, Tatyana, Alla Eirikh i Tatiana Noskova. "Factors Influencing Changes of the Initial Stable Water Isotopes Composition in the Seasonal Snowpack of the South of Western Siberia, Russia". Applied Sciences 12, nr 2 (10.01.2022): 625. http://dx.doi.org/10.3390/app12020625.

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Stable water isotopes in snowpack and snowfalls are widely used for understanding hydrological processes occurring in the seasonally snow-covered territories. The present study examines the main factors influencing changes of the initial stable water isotopes composition in the seasonal snow cover of the south of Western Siberia. Studies of the isotopic composition of snow precipitation and snow cover, as well as experiments with them, were carried out during two cold seasons of 2019–2021, and laser spectroscopy PICARRO L2130-i (WS-CRDS) was used for the determination of water isotope composition (δ18O and δD). The main changes in the isotopic composition of the snow cover layers in the studied region are associated with the existence of a vertical temperature gradient between the layers and with the penetration of soil moisture into the bottom layers in the absence of soil freezing. During the winter period, the sublimation from the top layer of snow is observed only at the moments of a sharp increase in the daily air temperature. At the end of winter, the contrast between day and night air temperatures determines the direction of the shift in the isotopic composition of the top layer of snow relative to the initial snow precipitation.

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Gribanov, K., J. Jouzel, V. Bastrikov, J. L. Bonne, F. M. Breon, M. Butzin, O. Cattani i in. "ECHAM5-wiso water vapour isotopologues simulation and its comparison with WS-CRDS measurements and retrievals from GOSAT and ground-based FTIR spectra in the atmosphere of Western Siberia". Atmospheric Chemistry and Physics Discussions 13, nr 1 (24.01.2013): 2599–640. http://dx.doi.org/10.5194/acpd-13-2599-2013.

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Abstract. Water stable isotopes provide integrated tracers of the atmospheric water cycle, affected by changes in air mass origin, non-convective and convective processes and continental recycling. Novel remote sensing and in situ measuring techniques have recently offered opportunities for monitoring atmospheric water vapour isotopic composition. Recently developed infrared laser spectrometers allow for continuous in situ measurements of surface water vapour δDv and δ18Ov. So far, very few intercomparison of measurements conducted using different techniques have been achieved at a given location, due to difficulties intrinsic to the comparison of integrated with local measurements. Nudged simulations conducted with high resolution isotopically enabled GCMs provide a consistent framework for comparison with the different types of observations. Here, we compare simulations conducted with the ECHAM5-wiso model with three types of water vapour isotopic data obtained during summer 2012 at the forest site of Kourovka, Western Siberia: daily mean GOSAT δDv soundings, hourly ground-based FTIR total atmospheric columnar δDv amounts, and in situ hourly Picarro δDv measurements. There is an excellent correlation between observed and predicted δDv at surface while the comparison between water column values derived from the model compares well with FTIR and GOSAT estimates. This research was supported by the grant of Russian government under the contract 11.G34.31.0064.

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Müller, Max, Stefan Weigl, Jennifer Müller-Williams, Matthias Lindauer, Thomas Rück, Simon Jobst, Rudolf Bierl i Frank-Michael Matysik. "Comparison of photoacoustic spectroscopy and cavity ring-down spectroscopy for ambient methane monitoring at Hohenpeißenberg". Atmospheric Measurement Techniques 16, nr 18 (25.09.2023): 4263–70. http://dx.doi.org/10.5194/amt-16-4263-2023.

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Abstract. With an atmospheric concentration of approximately 2000 parts per billion (ppbV, 10−9), methane (CH4) is the second most abundant greenhouse gas (GHG) in the atmosphere after carbon dioxide (CO2). The task of long-term and spatially resolved GHG monitoring to verify whether climate policy actions are effective is becoming more crucial as climate change progresses. In this paper we report the CH4 concentration readings of our photoacoustic (PA) sensor over a 5 d period at Hohenpeißenberg, Germany. As a reference device, a calibrated cavity ring-down spectrometer, Picarro G2301, from the meteorological observatory of the German Weather Service (DWD) was employed. Trace gas measurements with photoacoustic instruments promise to provide low detection limits at comparably low costs. However, PA devices are often susceptible to cross-sensitivities related to fluctuating environmental conditions, e.g. ambient humidity. The obtained results show that for PA sensor systems non-radiative relaxation effects induced by varying humidity are a non-negligible factor. Applying algorithm compensation techniques, which are capable of calculating the influence of non-radiative relaxation effects on the photoacoustic signal, increase the accuracy of the photoacoustic sensor significantly. With an average relative deviation of 1.11 % from the G2301, the photoacoustic sensor shows good agreement with the reference instrument.

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Chen, Changhua, Xuefa Wen, Jingyuan Wang i Qingjun Guo. "Continuous Measurements of Temporal and Vertical Variations in Atmospheric CO2 and Its δ13C in and above a Subtropical Plantation". Forests 12, nr 5 (7.05.2021): 584. http://dx.doi.org/10.3390/f12050584.

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Atmospheric CO2 dynamics in forest ecosystems are dependent on interactions between photosynthesis, respiration, and turbulent mixing processes; however, the carbon isotopic composition of atmospheric CO2 (δ13C) is not well established due to limited measurement reports. In this study, a seven-inlet profile system with a Picarro analyzer was developed to conduct continuous in situ measurements of CO2 and its δ13C in and above a subtropical plantation from 2015 to 2017. Results showed that ecosystem CO2 concentration was the lowest in the afternoon and reached its peak at dawn, which mirrored variations in its δ13C in and above the canopy. Inverse seasonal variations were apparent between CO2 and its δ13C in and above the canopy, and δ13C was positive during the peak growing season and negative at other times. Diel and seasonal variations in ecosystem CO2 and its δ13C were mainly affected by the vapor pressure deficit, followed by photosynthetic active radiation, temperature, and the enhanced vegetation index in and above the canopy; however, environmental and physiological factors had reverse or no effects near the forest floor. Nocturnal gradients of vertical variations in atmospheric CO2 and its δ13C were greater than diurnal variations due to weak turbulent mixing under more stable atmospheric conditions overnight. These results implicate that photosynthesis and respiration dominated CO2 dynamics above the canopy, while CO2 recycling by photosynthesis and turbulent mixing changed CO2 dynamics in the canopy.

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Berhanu, T. A., E. Satar, R. Schanda, P. Nyfeler, H. Moret, D. Brunner, B. Oney i M. Leuenberger. "Measurements of greenhouse gases at Beromünster tall tower station in Switzerland". Atmospheric Measurement Techniques Discussions 8, nr 10 (21.10.2015): 10793–822. http://dx.doi.org/10.5194/amtd-8-10793-2015.

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Abstract. In order to constrain the regional flux of greenhouse gases, an automated measurement system was built on an old radio tower at Beromünster, Switzerland. The measurement system has been running since November 2012 as part of the Swiss greenhouse gases monitoring network (CARBOCOUNT-CH), which is composed of four measurement sites across the country. The Beromünster tall tower has five sampling lines with inlets at 12.5, 44.6, 71.5, 131.6 and 212.5 m a.g.l., and it is equipped with a Picarro CRDS analyzer (G-2401), which continuously measures CO, CO2, CH4 and H2O. Sensors for detection of wind speed and direction, air temperature, barometric pressure, and humidity have also been installed at each height level. We have observed a non-negligible temperature effect in the calibration measurements, which was found to be dependent on the type of cylinder (steel or aluminum) as well as trace gas species (strongest for CO). From a target gas of known mixing ratio that has been measured once a day, we have calculated a long-term reproducibility of 2.79, 0.05 and 0.29 ppb for CO, CO2 and CH4, respectively over 19 months of measurements. The values obtained for CO2 and CH4 are compliant with the WMO recommendations, while the value calculated for CO is higher than the recommendation, which is mainly due to the above mentioned temperature effects.

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Liu, Yunsong, Jean-Daniel Paris, Mihalis Vrekoussis, Panayiota Antoniou, Christos Constantinides, Maximilien Desservettaz, Christos Keleshis i in. "Improvements of a low-cost CO₂ commercial nondispersive near-infrared (NDIR) sensor for unmanned aerial vehicle (UAV) atmospheric mapping applications". Atmospheric Measurement Techniques 15, nr 15 (2.08.2022): 4431–42. http://dx.doi.org/10.5194/amt-15-4431-2022.

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Abstract. Unmanned aerial vehicles (UAVs) provide a cost-effective way to fill in gaps between surface in situ observations and remotely sensed data from space. In this study, a novel portable CO2 measuring system suitable for operations on board small-sized UAVs has been developed and validated. It is based on a low-cost commercial nondispersive near-infrared (NDIR) CO2 sensor (Senseair AB, Sweden), with a total weight of 1058 g, including batteries. The system performs in situ measurements autonomously, allowing for its integration into various platforms. Accuracy and linearity tests in the lab showed that the precision remains within ± 1 ppm (1σ) at 1 Hz. Corrections due to temperature and pressure changes were applied following environmental chamber experiments. The accuracy of the system in the field was validated against a reference instrument (Picarro, USA) on board a piloted aircraft and it was found to be ± 2 ppm (1σ) at 1 Hz and ± 1 ppm (1σ) at 1 min. Due to its fast response, the system has the capacity to measure CO2 mole fraction changes at 1 Hz, thus allowing the monitoring of CO2 emission plumes and of the characteristics of their spatial and temporal distribution. Details of the measurement system and field implementations are described to support future UAV platform applications for atmospheric trace gas measurements.

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Johnson, Jennifer E., i Chris W. Rella. "Effects of variation in background mixing ratios of N2, O2, and Ar on the measurement of δ18O–H2O and δ2H–H2O values by cavity ring-down spectroscopy". Atmospheric Measurement Techniques 10, nr 8 (24.08.2017): 3073–91. http://dx.doi.org/10.5194/amt-10-3073-2017.

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Abstract. Cavity ring-down spectrometers have generally been designed to operate under conditions in which the background gas has a constant composition. However, there are a number of observational and experimental situations of interest in which the background gas has a variable composition. In this study, we examine the effect of background gas composition on a cavity ring-down spectrometer that measures δ18O–H2O and δ2H–H2O values based on the amplitude of water isotopologue absorption features around 7184 cm−1 (L2120-i, Picarro, Inc.). For background mixtures balanced with N2, the apparent δ18O values deviate from true values by −0.50 ± 0.001 ‰ O2 %−1 and −0.57 ± 0.001 ‰ Ar %−1, and apparent δ2H values deviate from true values by 0.26 ± 0.004 ‰ O2 %−1 and 0.42 ± 0.004 ‰ Ar %−1. The artifacts are the result of broadening, narrowing, and shifting of both the target absorption lines and strong neighboring lines. While the background-induced isotopic artifacts can largely be corrected with simple empirical or semi-mechanistic models, neither type of model is capable of completely correcting the isotopic artifacts to within the inherent instrument precision. The development of strategies for dynamically detecting and accommodating background variation in N2, O2, and/or Ar would facilitate the application of cavity ring-down spectrometers to a new class of observations and experiments.

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Kamp, Jesper Nørlem, Albarune Chowdhury, Anders Peter S. Adamsen i Anders Feilberg. "Negligible influence of livestock contaminants and sampling system on ammonia measurements with cavity ring-down spectroscopy". Atmospheric Measurement Techniques 12, nr 5 (17.05.2019): 2837–50. http://dx.doi.org/10.5194/amt-12-2837-2019.

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Abstract. Emission of ammonia (NH3) is a ubiquitous problem due to the adverse effects of NH3 on the environment and human health. The agricultural sector accounts for nearly all NH3 emissions in Europe. Hence, technologies for the abatement of NH3 emissions from this sector have been in strong demand in recent years. In order to document emissions and evaluate abatement technologies, there is a strong need for reliable NH3 measurement methods. Photoacoustic spectroscopy (PAS) is often used to measure NH3 concentrations, but recent research shows interference from compounds typically present in livestock production and during agricultural activities. In this work, the performance of cavity ring-down spectroscopy (CRDS) from Picarro, as an alternative to PAS, has been tested with respect to method validation under laboratory and field conditions. Potential interferences of 10 volatile organic compounds (VOCs) on CRDS NH3 measurement were tested with simultaneous VOC analysis performed by proton-transfer-reaction mass spectrometry (PTR-MS). Both laboratory and field calibrations show excellent linearity over a large dynamic range of NH3 concentrations. The analyzer shows a small humidity effect of up to a few ppb in the extreme case of a nearly water-saturated air stream. Apart from the negligible humidity dependency, no interferences of the tested VOCs were observed. Overall, the CRDS system performs satisfactory and is well suited for measurements of NH3 emissions from livestock production.

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Kolesnikova, Yulia, Viktoriia Semal, Оlga Nesterova, Simona Castaldi, Mariya Bovsun, Аnastasia Brikmans, Аnastasia Popova i Еlena Suvorova. "The effect on nitrogen oxide emission from agricultural soils". E3S Web of Conferences 175 (2020): 09014. http://dx.doi.org/10.1051/e3sconf/202017509014.

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The study investigates the effect of biochar on nitrous oxide emission in Endoargic Anthrosols in the southern territory of the Russian Far East. Biochar (bio-charcoal) was applied in the amounts of 1 kg/m2 and 3 kg/m2 in combination with organic and mineral fertilizers to drained and drain-free fields during the vegetation season, and the five-gas analyzer G2508 (Picarro) was used. Cumulative flows of N2O were estimated. The analysis revealed that biochar reduces the emissions and the cumulative flow of nitrous oxide. The higher the dose of biochar, the lower the emission and cumulative flows of nitrous oxide, regardless of a drainage system. Biochar (1 kg/m2) reduced the cumulative N2O flow from the soil by 52.2% throughout the experiment conducted, while a dose of 3 kg/m2 allowed for 97.8% reduction. The study found that organic and mineral fertilizers can be effectively used in combination with biochar, as N2O emission from the soil with mineral fertilizers is significantly higher than from the soil with organic fertilizers. Biochar (1 kg/m2) combined with organic fertilizers reduces N2O emission by 53.7%, while a dose of 3 kg/m2 can reduce emissions by 88.9%. Biochar (1 kg/m2) combined with mineral fertilizers reduced the flow of N2O by 17.5%, while a 3 kg/m2 dose of biochar used with mineral fertilizers reduced the emission by 85.3%.

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González-Hita, Luis, Miguel A. Mejía-González, Blanca Carteño-Martinez, Juan C. Aparicio-González i Dustin S. Mañon-Flores. "Composición isotópica de la precipitación en el Valle de Querétaro, México". Tecnología y ciencias del agua 14, nr 3 (1.05.2023): 56–88. http://dx.doi.org/10.24850/j-tyca-14-03-02.

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El uso de los isótopos estables del agua para determinar la relación entre la precipitación y la recarga/descarga del agua subterránea ha sido limitado en México. Una de las principales limitaciones es la falta de monitoreo de los isótopos estables de la lluvia. Este estudio presenta la caracterización de la composición isotópica (δ18O, δ2H, Exceso-d) del agua meteórica ocurrida en el Valle de Querétaro de septiembre de 2017 a julio de 2021. Los análisis de isótopos estables se realizaron en el laboratorio de hidrología isotópica del Instituto Mexicano de Tecnología del Agua (IMTA), utilizando analizadores láser Picarro L2110-i y Los Gatos Research LWIA-45EP. Por medio de una regresión lineal de mínimos cuadrados de los datos isotópicos se determinó la línea de agua meteórica del valle de Querétaro (LAMVQ), δ2H = 7.65 δ18O + 6.97. Esta línea tiene una pendiente y un intercepto menor al de la línea meteórica mundial (LMM). Los datos mostraron que los valores de la pendiente, del intercepto y del exceso de deuterio (d) dependen de la cantidad de lluvia. La LAMVQ tiene una pendiente e intercepto menor al de la LMM debido a evaporación secundaria de las precipitaciones pequeñas (< 30 mm mensual). Este colector forma parte de la Red Nacional de Monitoreo de la Composición Isotópica de la Precipitación Pluvial (RENIP), que el IMTA instaló en diversas provincias fisiográficas del país.

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Aggarwal, Shubham, Kevin J. Kuehner i Joe Magner. "Estimating Riparian Water Movement in an Incipient Karst Landscape—Minnesota, USA". Geographies 4, nr 1 (1.02.2024): 83–94. http://dx.doi.org/10.3390/geographies4010006.

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Understanding rain, ground, and surface water interactions in riparian zones is essential for hydrologic and environmental management. The novelty of this study lies in its revelation of isotopic shifts and consequent evaluation of hydrologic pathways and processes within the forested riparian zones of three distinct streams, valleys, and riparian systems in a carbonate-sandstone incipient karst landscape. We collected water samples from three southeastern Minnesota catchments: Trout Brook, Crystal Creek, and Bridge Creek. A Picarro L2130i was used to measure δ18O for oxygen, and δD for deuterium in units of ‰ (per mil). We estimated the global meteoric line for the study sites, built upon aquifer age dating, and explored aquifer transit time for the study sites using a simple seasonal amplitude model. The results showed small amplitudes for 2020 and 2021, suggesting that bedrock aquifer water was the primary source water with a mean core transit time greater than 10 years. All three catchments were different but had similar bedrock valley types and riparian sediment. The primary driving factor was the seasonal precipitation input mixing with existing water. In a normal to wetter year, the isotopic data showed larger amplitude shifts between seasons with trendlines that adjusted depending on the temperature of the new water additions. The proposed approach is valuable in revealing complex hydrologic processes and pathways and can contribute extensively to the planning and management of karst riparian systems.

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40

Malowany, K., J. Stix, A. Van Pelt i G. Lucic. "H2S interference on CO2 isotopic measurements using a Picarro G1101-i cavity ring-down spectrometer". Atmospheric Measurement Techniques 8, nr 10 (6.10.2015): 4075–82. http://dx.doi.org/10.5194/amt-8-4075-2015.

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Abstract. Cavity ring-down spectrometers (CRDSs) have the capacity to make isotopic measurements of CO2 where concentrations range from atmospheric (~ 400 ppm) to 6000 ppm. Following field trials, it has come to light that the spectrographic lines used for CO2 have an interference with elevated (higher than ambient) amounts of hydrogen sulfide (H2S), which causes significant depletions in the δ13C measurement by the CRDSs. In order to deploy this instrument in environments with elevated H2S concentrations (i.e., active volcanoes), we require a robust method for eliminating this interference. Controlled experiments using a Picarro G1101-i optical spectrometer were done to characterize the H2S interference at varying CO2 and H2S concentrations. The addition of H2S to a CO2 standard gas reveals an increase in the 12CO2 concentration and a more significant decrease in the 13CO2 concentration, resulting in a depleted δ13C value. Reacting gas samples containing H2S with copper prior to analysis can eliminate this effect. Models post-dating the G1101-i carbon isotope analyzer have maintained the same spectral lines for CO2 and are likely to have a similar H2S response at elevated H2S concentrations. It is important for future work with CRDS, particularly in volcanic regions where H2S is abundant, to be aware of the H2S interference on the CO2 spectroscopic lines and to remove all H2S prior to analysis. We suggest employing a scrub composed of copper to remove H2S from all gas samples that have concentrations in excess of 1 ppb.

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Zhao, Zhujun, Qing He, Zhongqi Lu, Quanwei Zhao i Jianlin Wang. "Analysis of Atmospheric CO2 and CO at Akedala Atmospheric Background Observation Station, a Regional Station in Northwestern China". International Journal of Environmental Research and Public Health 19, nr 11 (6.06.2022): 6948. http://dx.doi.org/10.3390/ijerph19116948.

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Air samples were collected by flasks and analyzed via a Picarro G2401 gas analyzer for carbon dioxide (CO2) and carbon monoxide (CO) at the Akedala Atmospheric Background Station in Xinjiang, China, from September 2009 to December 2019, to analyze the changes in the characteristics of atmospheric CO2 and CO and determine the sources. The results show that the annual average CO2 concentration showed an increasing trend (growth rate: 1.90 ppm year−1), ranging from 389.80 to 410.43 ppm, and the annual average CO concentration also showed an increasing trend (growth rate: 1.78 ppb year−1), ranging from 136.30 to 189.82 ppb. The CO2 concentration and growth rate were the highest in winter, followed by autumn, spring, and summer. The CO concentration and growth rate were also the highest in winter due to anthropogenic emissions, ecosystem effects, and diffusion conditions. The main trajectories of CO2 and CO determined by the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model were parallel to the Irtysh River valley and then passed through the Old Wind Pass. Furthermore, the main source regions of CO2 and CO at the Akedala Station were eastern Kazakhstan, southern Russia, western Mongolia, and the Xinjiang Tianshan North Slope Economic Zone of China. This study reflects the characteristics of long-term changes in CO2 and CO concentrations at the Akedala station and provides fundamental data for the studies on environmental changes and climate change in Central Asia.

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Kakareka, S. V., T. I. Kukharchyk, A. A. Ekaykin i Yu G. Giginyak. "Stable isotopes in the snow of the coastal areas of Antarctica". Doklady of the National Academy of Sciences of Belarus 65, nr 4 (2.09.2021): 495–502. http://dx.doi.org/10.29235/1561-8323-2021-65-4-495-502.

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The first results of study of stable isotopes of oxygen (δ18O) and hydrogen (δD) in the snow samples taken on the islands of Marguerite Bay (Antarctic Peninsula), in the Vecherny Oasis (Enderby Land), and Larsemann Hills (Princess Elizabeth Land) by the participants of the 12th Belarusian Antarctic Expedition (January–March 2020) are presented. The concentration of water isotopes: deuterium (D) and oxygen-18 (18O) in the samples was determined using a laser isotope composition analyzer Picarro L2130. A total of 32 snow samples were analyzed. The statistical parameters of the isotopic composition of snow were estimated, and the main differences in the content of δ18O and δD between the study areas were shown. A decrease in the content of heavy oxygen and hydrogen isotopes in the newly fallen snow to the old snow of the surface horizons is shown. The maximum values of δ18O and δD are typical for the Maritime Antarctica, decreasing towards the coastal zone and further – towards its continental part. The possible factors affecting the isotope content are described. It is shown that the monitoring of the isotope composition can be an integral part of the monitoring of climatic changes within the area of operation of the Belarusian Antarctic Expedition. The study of the isotopic composition of surface snow is important for the reconstruction of the paleoclimate of the marginal zone of the Antarctic ice sheet based on the ice cores study.

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Mathuthu, Joseph, Naomi Dikeledi Mokhine, Namhla Mkiva, Samuel Che Nde, Ingrid Dennis, Johan Hendriks, Lobina Palamuleni, Tebogo Gilbert Kupi i Manny Mathuthu. "Determining Water Isotope Compositions for the IAEA WICO and North West Villages, South Africa". Water 13, nr 20 (9.10.2021): 2801. http://dx.doi.org/10.3390/w13202801.

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Deuterium (2H) and oxygen 18 (18O) stable isotopes in water are the key indicators of hydrological and ecological patterns and processes. The water isotopes δ2H and δ18O have been employed widely as tracers in hydrological and ecological research, as they are integrated into geological and biological systems in a predictable manner. The aim of this study was to determine the water isotope composition of the International Atomic Energy Agency’s (IAEA) Water Isotope Inter-laboratory Comparison (WICO) samples and to determine the Local Meteoric Water Line for North West Province (NWP) villages in South Africa. The IAEA WICO 2020 samples were obtained from the IAEA, Vienna, and borehole water samples from selected villages in the North West province of South Africa were randomly collected to investigate the relationship between the stable isotopes (18O and 2H) and the climate in underground water aquifers. A cavity ring-down spectroscopy analyzer with laser-current-tuned cavity resonance, Picarro L2140-i, was used to measure triple water–isotope ratios with high precision. The IAEA WICO results obtained for the d-excess were in a satisfactory range and the margins of error were close to those required by the IAEA. The δ2H values ranged between −33.00‰ and −8.00‰, while the δ18O values ranged between −5.50‰ and −2.00‰. The results of this work have shown that our water science and management lab is capable of undertaking inter-laboratory comparisons for the IAEA.

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Peltola, O., I. Mammarella, S. Haapanala, G. Burba i T. Vesala. "Field intercomparison of four methane gas analysers suitable for eddy covariance flux measurements". Biogeosciences Discussions 9, nr 12 (12.12.2012): 17651–706. http://dx.doi.org/10.5194/bgd-9-17651-2012.

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Abstract. Performances of four methane gas analyzers suitable for eddy covariance measurements are assessed. The assessment and comparison was performed by analyzing eddy covariance data obtained during summer 2010 (1 April to 26 October) at a pristine fen, Siikaneva, Southern Finland. High methane fluxes with pronounced seasonality have been measured at this fen. The four participating methane gas analyzers are commercially available closed-path units TGA-100A (Campbell Scientific Inc., USA), RMT-200 (Los Gatos Research, USA), G1301-f (Picarro Inc., USA) and an early prototype open-path unit Prototype-7700 (LI-COR Biosciences, USA). The RMT-200 functioned most reliably throughout the measurement campaign, during low and high flux periods. Methane fluxes from RMT-200 and G1301-f had the smallest random errors and the fluxes agree remarkably well throughout the measurement campaign. Cospectra and power spectra calculated from RMT-200 and G1301-f data agree well with corresponding temperature spectra during a high flux period. None of the gas analysers showed statistically significant diurnal variation for methane flux. Prototype-7700 functioned only for a short period of time, over one month, in the beginning of the measurement campaign during low flux period, and thus, its overall accuracy and long-term performance were not assessed. Prototype-7700 is a practical choice for measurement sites in remote locations due to its low power demand, however if only the performance in this intercomparison is considered, RMT-200 performed the best and is the recommended choice if a new fast response methane gas analyser is needed.

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Herbstritt, Barbara, Benjamin Gralher i Markus Weiler. "Continuous, near-real-time observations of water stable isotope ratios during rainfall and throughfall events". Hydrology and Earth System Sciences 23, nr 7 (17.07.2019): 3007–19. http://dx.doi.org/10.5194/hess-23-3007-2019.

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Abstract. The water isotopic composition of throughfall is affected by complex diffusive exchange with ambient water vapour, evaporative enrichment of heavy isotopes, and mixing processes in the tree canopy. All interception processes occur simultaneously in space and time, generating a complex pattern of throughfall depth and water isotopic composition. This pattern ultimately cascades through the entire hydrologic system and is therefore crucial for isotope studies in catchment hydrology, where recharge areas are often forested, while reference meteorological stations are generally in the open. For the quasi real-time observation of the water isotopic composition (δ18O and δ2H) of both gross precipitation and throughfall, we developed an approach combining a membrane contactor (Membrana) with a laser-based Cavity Ring-Down Spectrometer (CRDS, Picarro), obtaining isotope readings every 2 s. A setup with two CRDS instruments in parallel analysing gross precipitation and throughfall simultaneously was used for the continuous observation of the temporal effect of interception processes on the stable isotopes of water. All devices were kept small to minimize dead volume with time lags of only 4 min for water from the rainfall collectors to the isotope analysers to increase the temporal resolution of isotope observations. Complementarily, meteorological variables were recorded at high temporal resolution at the same location. The achieved evolution from discrete liquid or event-based bulk samples to continuous measurements allows for direct comparison of water stable isotope data with common meteorological measurements. Future improvements of the spatial representativeness will make our approach an even more powerful tool towards detailed insight into the dynamic processes contributing to interception during rainfall events.

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46

Yang, Yang, Minqiang Zhou, Ting Wang, Bo Yao, Pengfei Han, Denghui Ji, Wei Zhou, Yele Sun, Gengchen Wang i Pucai Wang. "Spatial and temporal variations of CO2 mole fractions observed at Beijing, Xianghe, and Xinglong in North China". Atmospheric Chemistry and Physics 21, nr 15 (6.08.2021): 11741–57. http://dx.doi.org/10.5194/acp-21-11741-2021.

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Abstract. Atmospheric CO2 mole fractions are observed at Beijing (BJ), Xianghe (XH), and Xinglong (XL) in North China using Picarro G2301 cavity ring-down spectroscopy instruments. The measurement system is described comprehensively for the first time. The geographical distances among these three sites are within 200 km, but they have very different surrounding environments: BJ is inside the megacity; XH is in the suburban area; XL is in the countryside on a mountain. The mean and standard deviation of CO2 mole fractions at BJ, XH, and XL between October 2018 and September 2019 are 448.4±12.8, 436.0±9.2, and 420.6±8.2 ppm, respectively. The seasonal variations of CO2 at these three sites are similar, with a maximum in winter and a minimum in summer, which is dominated by the terrestrial ecosystem. However, the seasonal variations of CO2 at BJ and XH are more affected by human activities as compared to XL. Using CO2 at XL as the background, CO2 enhancements are observed simultaneously at BJ and XH. The diurnal variations of CO2 are driven by the boundary layer height, photosynthesis, and human activities at BJ, XH, and XL. We also compare the CO2 measurements at BJ, XH, and XL with five urban sites in the USA, and it is found that the CO2 mean concentration at BJ is the largest. Moreover, we address the impact of the wind on the CO2 mole fractions at BJ and XL. This study provides an insight into the spatial and temporal variations of CO2 mole fractions in North China.

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47

Malowany, K., J. Stix, A. Van Pelt i G. Lucic. "H2S interference on CO2 isotopic measurements using a Picarro G1101-i cavity ring-down spectrometer". Atmospheric Measurement Techniques Discussions 8, nr 6 (5.06.2015): 5651–75. http://dx.doi.org/10.5194/amtd-8-5651-2015.

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Abstract. Cavity ring-down spectrometers (CRDS) have the capacity to make isotopic measurements of CO2 where concentrations range from atmospheric (~ 400 ppm) to 6000 ppm. Following field trials, it has come to light that the spectrographic lines used for CO2 have an interference with elevated (higher than ambient) amounts of hydrogen sulfide (H2S), which causes significant depletions in the δ13C measurement by the CRDS. In order to deploy this instrument in environments with elevated H2S concentrations (i.e., active volcanoes), we require a robust method for eliminating this interference. Controlled experiments using a Picarro G1101-i optical spectrometer were done to characterize the H2S interference at varying CO2 and H2S concentrations. The addition of H2S to a CO2 standard gas reveals an increase in the 12CO2 concentration and a more significant decrease in the 13CO2 concentration, resulting in a depleted δ13C value. Reacting gas samples containing H2S with copper prior to analysis can eliminate this effect. However, experiments also revealed that the addition of H2S to CO2 results in the formation of carbonyl sulfide (OCS) and carbon disulfide (CS2), causing a decrease in the overall CO2 concentration without affecting the δ13C value. It is important for future work with CRDS, particularly in volcanic regions where H2S is abundant, to be aware of the H2S interference on the CO2 spectroscopic lines and to remove all H2S prior to analysis. We suggest employing a scrub composed of copper to remove H2S from all gas samples that have concentrations in excess of 1 ppb.

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TAVARES, Flavia A., Jefferson C. SIMÕES, Ronaldo T. BERNARDO, Nicoli P. GERHARD, Gino CASASSA i Luciano MARQUETTO. "Razões de isótopos estáveis em um testemunho de firn do manto de gelo da Antártica Oriental". Pesquisas em Geociências 47, nr 2 (22.10.2020): e094026. http://dx.doi.org/10.22456/1807-9806.108585.

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O testemunho de firn IC-02 (88°01’21,3"S e 82°04’21,7"W), atingindo 41,82 m de profundidade, foi coletado no manto de gelo da Antártica Oriental, durante uma travessia científica chileno-brasileira no verão austral de 2004/2005. Este estudo visou à determinação da variabilidade sazonal das razões isotópicas de oxigênio e hidrogênio (ẟ18O e ẟD) e da taxa anual de acumulação de neve. O testemunho foi subamostrado em um sistema de fusão contínua e o conteúdo isotópico determinado por espectrometria a laser de cavidade ressonante do tipo ring-down (WS-CRDS, sistema Picarro). A série de ẟ18O varia entre ‑50,77‰ e ‑41,40‰ (média -46,39 ± 1,37‰), enquanto o ẟD varia entre -408,18‰ e ‑323,85‰ (média -367,43 ± 12,51‰). O excesso de deutério (d) tem média de 4,36 ± 2,66‰. O testemunho representa 85 ± 3 anos de acumulação de neve, ou seja, uma taxa média de 152 ± 64 mm ano‑1 em equivalente d'água. A partir da década de 1990 ocorreu a diminuição da média anual de δD concomitante com o aumento da taxa de acumulação de neve (17% entre 1974 e 2003). O aumento desta acumulação poderia estar associado à maior mobilização de neve à deriva (drift snow) até o sítio de deposição, associada à maior advecção de massas de ar oceânicas vindas dos mares antárticos (Amundsen, Bellingshausen, Weddell e Lazarev). Tal interpretação é apoiada pelo aumento da velocidade dos ventos zonais, conforme observado nos campos de anomalias de altura geopotencial, vento zonal e temperatura em 500 mb da reanálise NCEP/NCAR.

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Lnglada, Rafael. "Picasso y el escudo de la ciudad de Málaga". Boletín de Arte, nr 17 (9.06.2022): 481–84. http://dx.doi.org/10.24310/bolarte.1996.vi17.14884.

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Desde que Pablo Ruiz Picasso pintase, hacia 1890, sus dos primeros óleos, El picador amarillo –reflejo de su incipiente y dilatada pasión por lo taurino– y Vista del puerto de Málaga, versión de un cuadro de su padre, quien, a su vez, lo había copiado del marinista Emilio Ocón, las pruebas del universal artista que remiten a la etapa de su infancia malagueña son múltiples.

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Welp, L. R., R. F. Keeling, R. F. Weiss, W. Paplawsky i S. Heckman. "Design and performance of a Nafion dryer for continuous operation at CO2 and CH4 air monitoring sites". Atmospheric Measurement Techniques Discussions 5, nr 4 (7.08.2012): 5449–68. http://dx.doi.org/10.5194/amtd-5-5449-2012.

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Abstract. In preparation for the routine deployment of the Earth Networks greenhouse gas monitoring network, we have designed and tested a simple method for drying ambient air to below 0.2% mole fraction H2O using a Nafion dryer. The inlet was designed for use with a Picarro model G2301 cavity ring down spectrometer (CRDS) CO2/CH4/H2O analyzer. The analyzer measures water vapor mixing ratio at the same frequency as CO2 and CH4 and then corrects for the dilution and peak broadening effects of H2O on the CO2 and CH4 mixing ratios. This analyzer is remarkably stable and performs well on water vapor correction tests, but there is potentially an added benefit of reducing the dependence on the H2O correction for long term field measurement programs. Substantially lowering the amount of H2O in the sample can reduce uncertainties in the applied H2O corrections by an order of magnitude or more, and eliminate the need to determine an instrument-specific H2O correction factor and to verify its stability over time. Our Nafion drying inlet system takes advantage of the extra capacity of the analyzer pump to redirect 30% of the dry gas exiting the Nafion to the outer shell side of the dryer and has no consumables. We tested the Nafion dryer against a cryotrap (−95 °C) method for removing H2O and found that it does not significantly alter the CO2 and CH4 dry mixing ratios of the sample gas. Systematic differences between the drying methods were at the level of 0.05 ppm in CO2 and 0.1 ppb in CH4 for the wet-air tests, well within the WMO compatibility guidelines.

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