Pub Date : 2024-08-02DOI: 10.5194/egusphere-2024-2365
Maximilian Reuter, Michael Hilker, Stefan Noël, Antonio Di Noia, Michael Weimer, Oliver Schneising, Michael Buchwitz, Heinrich Bovensmann, John P. Burrows, Hartmut Bösch, Ruediger Lang
Abstract. Carbon dioxide (CO2) and methane (CH4) are the most important anthropogenic greenhouse gases and the main drivers of climate change. Monitoring their concentrations from space helps to detect and quantify anthropogenic emissions, supporting the mitigation efforts urgently needed to meet the primary objective of the United Nations Framework Convention on Climate Change (UNFCCC) Paris Agreement to limit the global average temperature increase to well below 2 °C above pre-industrial levels. In addition, satellite observations can be used to quantify natural sources and sinks improving our understanding of the carbon cycle. Advancing these goals is the motivation for the European Copernicus CO2 monitoring mission CO2M. The necessary accuracy and precision requirements for the measured quantities XCO2 and XCH4 (the column-averaged dry-air mixing ratios of CO2 and CH4) are demanding. According to the CO2M mission requirements, the spatial and temporal variability of the systematic errors of XCO2 and XCH4 shall not exceed 0.5 ppm and 5 ppb, respectively. The stochastic errors due to instrument noise shall not exceed 0.7 ppm for XCO2 and 10 ppb for XCH4. Conventional so-called full-physics algorithms for retrieving XCO2 and/or XCH4 from satellite-based measurements of reflected solar radiation are typically computationally intensive and still usually require empirical bias corrections based on supervised machine learning methods. Here we present the retrieval algorithm NRG-CO2M (Neural networks for Remote sensing of Greenhouse gases from CO2M), which derives XCO2 and XCH4 from CO2M radiance measurements with minimal computational effort using artificial neural networks (ANNs). Since CO2M will not be launched until 2026, our study is based on simulated measurements over land surfaces from a comprehensive observing system simulation experiment (OSSE). We employ a hybrid learning approach that combines advantages of simulation-based and measurement-based training data to ensure coverage of a wide range of XCO2 and XCH4 values making the training data also representative of future concentrations. The algorithm's postprocessing is designed to achieve a high data yield of about 80 % of all cloud-free soundings. The spatio-temporal systematic errors of XCO2 and XCH4 amount 0.44 ppm and 2.45 ppb, respectively. The average single sounding precision is 0.41 ppm for XCO2 and 2.74 ppb for XCH4. Therefore, the presented retrieval method has the potential to meet the demanding CO2M mission requirements for XCO2 and XCH4.
{"title":"Retrieving the atmospheric concentrations of carbon dioxide and methane from the European Copernicus CO2M satellite mission using artificial neural networks","authors":"Maximilian Reuter, Michael Hilker, Stefan Noël, Antonio Di Noia, Michael Weimer, Oliver Schneising, Michael Buchwitz, Heinrich Bovensmann, John P. Burrows, Hartmut Bösch, Ruediger Lang","doi":"10.5194/egusphere-2024-2365","DOIUrl":"https://doi.org/10.5194/egusphere-2024-2365","url":null,"abstract":"<strong>Abstract.</strong> Carbon dioxide (CO<sub>2</sub>) and methane (CH<sub>4</sub>) are the most important anthropogenic greenhouse gases and the main drivers of climate change. Monitoring their concentrations from space helps to detect and quantify anthropogenic emissions, supporting the mitigation efforts urgently needed to meet the primary objective of the United Nations Framework Convention on Climate Change (UNFCCC) Paris Agreement to limit the global average temperature increase to well below 2 °C above pre-industrial levels. In addition, satellite observations can be used to quantify natural sources and sinks improving our understanding of the carbon cycle. Advancing these goals is the motivation for the European Copernicus CO<sub>2</sub> monitoring mission CO2M. The necessary accuracy and precision requirements for the measured quantities XCO2 and XCH4 (the column-averaged dry-air mixing ratios of CO<sub>2</sub> and CH<sub>4</sub>) are demanding. According to the CO2M mission requirements, the spatial and temporal variability of the systematic errors of XCO2 and XCH4 shall not exceed 0.5 ppm and 5 ppb, respectively. The stochastic errors due to instrument noise shall not exceed 0.7 ppm for XCO2 and 10 ppb for XCH4. Conventional so-called full-physics algorithms for retrieving XCO2 and/or XCH4 from satellite-based measurements of reflected solar radiation are typically computationally intensive and still usually require empirical bias corrections based on supervised machine learning methods. Here we present the retrieval algorithm NRG-CO2M (Neural networks for Remote sensing of Greenhouse gases from CO2M), which derives XCO2 and XCH4 from CO2M radiance measurements with minimal computational effort using artificial neural networks (ANNs). Since CO2M will not be launched until 2026, our study is based on simulated measurements over land surfaces from a comprehensive observing system simulation experiment (OSSE). We employ a hybrid learning approach that combines advantages of simulation-based and measurement-based training data to ensure coverage of a wide range of XCO2 and XCH4 values making the training data also representative of future concentrations. The algorithm's postprocessing is designed to achieve a high data yield of about 80 % of all cloud-free soundings. The spatio-temporal systematic errors of XCO2 and XCH4 amount 0.44 ppm and 2.45 ppb, respectively. The average single sounding precision is 0.41 ppm for XCO2 and 2.74 ppb for XCH4. Therefore, the presented retrieval method has the potential to meet the demanding CO2M mission requirements for XCO2 and XCH4.","PeriodicalId":8619,"journal":{"name":"Atmospheric Measurement Techniques","volume":"181 1","pages":""},"PeriodicalIF":3.8,"publicationDate":"2024-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141881399","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract. Aerosols have important effects on both local and global climate, as well as on clouds and precipitations. We present some original results of the airborne AErosol RadiatiOn and CLOud in Southern Africa (AEROCLO-sA) field campaign led in Namibia in August and September 2017. In order to quantify the aerosols radiative impact on the Namibian regional radiative budget, we use an innovative approach that combines the OSIRIS polarimeter and lidar data to derive heating rate of the aerosols. To calculate this parameter, we use a radiative transfer code and meteorological parameters provided by dropsondes. This approach is evaluated during massive transports of biomass burning particles above clouds. We present vertical profiles of heating rates computed in the solar and thermal parts of the spectrum. Our results indicated strong positive heating rate values retrieved above clouds due to aerosols, between +2 and +5 Kelvin per day (vertically averaged). Within the smoke layer, water vapor's cooling effect through infrared radiation generally balances its warming effect from solar radiation. At the top of the layer, a stronger cooling effect of −1.5 K/day often dominates due to water vapor. In order to validate this methodology, we use irradiance measurements acquired during sounding performed with the aircraft during dedicated parts of the flights, which provides direct measurements of irradiances distribution and heating rates in function of the altitude. Finally, we discuss the possibility to apply this method to available and future spaceborne passive and active sensors.
{"title":"Synergy of active and passive airborne observations for heating rates calculation during the AEROCLO-SA field campaign in Namibia","authors":"Mégane Ventura, Fabien Waquet, Isabelle Chiapello, Gérard Brogniez, Frédéric Parol, Frédérique Auriol, Rodrigue Loisil, Cyril Delegove, Luc Blarel, Oleg Dubovik, Marc Mallet, Cyrille Flamant, Paola Formenti","doi":"10.5194/amt-2024-121","DOIUrl":"https://doi.org/10.5194/amt-2024-121","url":null,"abstract":"<strong>Abstract.</strong> Aerosols have important effects on both local and global climate, as well as on clouds and precipitations. We present some original results of the airborne AErosol RadiatiOn and CLOud in Southern Africa (AEROCLO-sA) field campaign led in Namibia in August and September 2017. In order to quantify the aerosols radiative impact on the Namibian regional radiative budget, we use an innovative approach that combines the OSIRIS polarimeter and lidar data to derive heating rate of the aerosols. To calculate this parameter, we use a radiative transfer code and meteorological parameters provided by dropsondes. This approach is evaluated during massive transports of biomass burning particles above clouds. We present vertical profiles of heating rates computed in the solar and thermal parts of the spectrum. Our results indicated strong<span> pos</span><span>i</span><span>tive</span> heating rate values retrieved above clouds due to aerosols, between +2 and +5 Kelvin per day (vertically averaged). Within the smoke layer, water vapor's cooling effect through infrared radiation <span>generally </span>balances its warming effect from solar radiation. At the top of the layer, a stronger cooling effect of −1.5 K/day often dominates due to water vapor. In order to validate this methodology, we use irradiance measurements acquired during sounding performed with the aircraft during dedicated parts of the flights, which provides direct measurements of irradiances distribution and heating rates in function of the altitude. Finally, we discuss the possibility to apply this method to available and future spaceborne passive and active sensors.","PeriodicalId":8619,"journal":{"name":"Atmospheric Measurement Techniques","volume":"45 1","pages":""},"PeriodicalIF":3.8,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141864026","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-01DOI: 10.5194/amt-17-4581-2024
Dhiraj K. Singh, Eric R. Pardyjak, Timothy J. Garrett
Abstract. It is a challenge to obtain accurate measurements of the microphysical properties of delicate, structurally complex, frozen, and semi-frozen hydrometeors. We present a new technique for the real-time measurement of the density of freshly fallen individual snowflakes. A new thermal-imaging instrument, the Differential Emissivity Imaging Disdrometer (DEID), has been shown through laboratory and field experiments to be capable of providing accurate estimates of individual snowflake and bulk snow hydrometeor density (which can be interpreted as the snow-to-liquid ratio or SLR). The method exploits the rate of heat transfer during the melting of a hydrometeor on a heated metal plate, which is a function of the temperature difference between the hotplate surface and the top of the hydrometeor. The product of the melting speed and melting time yields an effective particle thickness normal to the hotplate surface, which can then be used in combination with the particle mass and area on the plate to determine a particle density. Uncertainties in estimates of particle density are approximately 4 % based on calibrations with laboratory-produced particles made from water and frozen solutions of salt and water and field comparisons with both high-resolution imagery of falling snow and traditional snowpack density measurements obtained at 12 h intervals. For 17 storms, individual particle densities vary from 19 to 495 kg m−3, and storm mean snow densities vary from 40 to 100 kg m−3. We observe probability distribution functions for hydrometeor density that are nearly Gaussian with kurtosis of ≈ 3 and skewness of ≈ 0.01.
摘要要精确测量结构复杂的冰冻和半冰冻水介质的微物理性质是一项挑战。我们介绍了一种实时测量刚落下的单片雪花密度的新技术。通过实验室和现场实验证明，一种新型热成像仪器--差分发射率成像仪（DEID）能够准确估算单片雪花和大块雪水流体的密度（可解释为雪液比或 SLR）。该方法利用了水流星在加热金属板上融化时的传热速率，该速率是热板表面与水流星顶部之间温度差的函数。熔化速度与熔化时间的乘积可得出沿加热板表面法线方向的有效颗粒厚度，然后将其与颗粒质量和板上面积结合使用，即可确定颗粒密度。颗粒密度估算值的不确定性约为 4%，这是用实验室生产的由水和盐及水的冷冻溶液制成的颗粒进行校准，以及与高分辨率降雪图像和以 12 小时间隔获得的传统雪堆密度测量结果进行实地比较后得出的结果。在 17 次暴风雪中，单个颗粒密度从 19 kg m-3 到 495 kg m-3 不等，暴风雪平均密度从 40 kg m-3 到 100 kg m-3 不等。我们观察到水流密度的概率分布函数接近高斯分布，峰度≈3，偏度≈0.01。
{"title":"Time-resolved measurements of the densities of individual frozen hydrometeors and fresh snowfall","authors":"Dhiraj K. Singh, Eric R. Pardyjak, Timothy J. Garrett","doi":"10.5194/amt-17-4581-2024","DOIUrl":"https://doi.org/10.5194/amt-17-4581-2024","url":null,"abstract":"Abstract. It is a challenge to obtain accurate measurements of the microphysical properties of delicate, structurally complex, frozen, and semi-frozen hydrometeors. We present a new technique for the real-time measurement of the density of freshly fallen individual snowflakes. A new thermal-imaging instrument, the Differential Emissivity Imaging Disdrometer (DEID), has been shown through laboratory and field experiments to be capable of providing accurate estimates of individual snowflake and bulk snow hydrometeor density (which can be interpreted as the snow-to-liquid ratio or SLR). The method exploits the rate of heat transfer during the melting of a hydrometeor on a heated metal plate, which is a function of the temperature difference between the hotplate surface and the top of the hydrometeor. The product of the melting speed and melting time yields an effective particle thickness normal to the hotplate surface, which can then be used in combination with the particle mass and area on the plate to determine a particle density. Uncertainties in estimates of particle density are approximately 4 % based on calibrations with laboratory-produced particles made from water and frozen solutions of salt and water and field comparisons with both high-resolution imagery of falling snow and traditional snowpack density measurements obtained at 12 h intervals. For 17 storms, individual particle densities vary from 19 to 495 kg m−3, and storm mean snow densities vary from 40 to 100 kg m−3. We observe probability distribution functions for hydrometeor density that are nearly Gaussian with kurtosis of ≈ 3 and skewness of ≈ 0.01.","PeriodicalId":8619,"journal":{"name":"Atmospheric Measurement Techniques","volume":"7 1","pages":""},"PeriodicalIF":3.8,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141864025","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Maryam Pashayi, Mehran Satari, Mehdi Momeni Shahraki
Abstract. Accurately determining Aerosol Optical Depth (AOD) across various altitudes with sufficient spatial and temporal resolution is crucial for effective aerosol monitoring, given the significant variations over time and space. While ground-based observations provide detailed vertical profiles, satellite data are crucial for addressing spatial and temporal gaps. This study utilizes profiles from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) and data from the Spinning Enhanced Visible and Infrared Imager (SEVIRI) to estimate vertical AOD values at 1.5, 3, 5, and 10 km layers. These estimations are achieved with spatial and temporal resolutions of 3 km × 3 km and 15 minutes, respectively, over Europe. We employed machine learning models—XGBoost (XGB) and Random Forest (RF)—trained on SEVIRI data from 2017 to 2019 for the estimations. Validation using CALIOP AOD retrievals in 2020 confirmed the reliability of our findings, emphasizing the importance of wind speed (Ws) and wind direction (Wd) in improving AOD estimation accuracy. A comparison between seasonal and annual models revealed slight variations in accuracy, leading to the selection of annual models as the preferred approach for estimating SEVIRI AOD profiles. Among the annual models, the RF model demonstrated superior performance over the XGB model at higher layers, yielding more reliable AOD estimations. Further validation using data from EARLINET stations across Europe in 2020 indicated that the XGB model achieved better agreement with EARLINET AOD profiles, with R2 values of 0.81, 0.77, 0.71, and 0.56, and RMSE values of 0.03, 0.01, 0.02, and 0.005, respectively.
{"title":"Vertical Retrieval of AOD using SEVIRI data, Case Study: European Continent","authors":"Maryam Pashayi, Mehran Satari, Mehdi Momeni Shahraki","doi":"10.5194/amt-2024-105","DOIUrl":"https://doi.org/10.5194/amt-2024-105","url":null,"abstract":"<strong>Abstract.</strong> Accurately determining Aerosol Optical Depth (AOD) across various altitudes with sufficient spatial and temporal resolution is crucial for effective aerosol monitoring, given the significant variations over time and space. While ground-based observations provide detailed vertical profiles, satellite data are crucial for addressing spatial and temporal gaps. This study utilizes profiles from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) and data from the Spinning Enhanced Visible and Infrared Imager (SEVIRI) to estimate vertical AOD values at 1.5, 3, 5, and 10 km layers. These estimations are achieved with spatial and temporal resolutions of 3 km × 3 km and 15 minutes, respectively, over Europe. We employed machine learning models—XGBoost (XGB) and Random Forest (RF)—trained on SEVIRI data from 2017 to 2019 for the estimations. Validation using CALIOP AOD retrievals in 2020 confirmed the reliability of our findings, emphasizing the importance of wind speed (Ws) and wind direction (Wd) in improving AOD estimation accuracy. A comparison between seasonal and annual models revealed slight variations in accuracy, leading to the selection of annual models as the preferred approach for estimating SEVIRI AOD profiles. Among the annual models, the RF model demonstrated superior performance over the XGB model at higher layers, yielding more reliable AOD estimations. Further validation using data from EARLINET stations across Europe in 2020 indicated that the XGB model achieved better agreement with EARLINET AOD profiles, with R<sup>2</sup> values of 0.81, 0.77, 0.71, and 0.56, and RMSE values of 0.03, 0.01, 0.02, and 0.005, respectively.","PeriodicalId":8619,"journal":{"name":"Atmospheric Measurement Techniques","volume":"8 1","pages":""},"PeriodicalIF":3.8,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141864028","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-31DOI: 10.5194/amt-17-4553-2024
Finja Löher, Esther Borrás, Amalia Muñoz, Anke Christine Nölscher
Abstract. The photooxidation of volatile organic compounds (VOCs) in the troposphere has important implications for air quality, weather, and climate. A deeper understanding of the underlying mechanisms can be achieved by studying these reactions under controlled conditions and analysing the emerging photooxidation products. This requires dedicated laboratory infrastructure as well as sensitive and selective analytical techniques. Here, we constructed a new 300 L indoor Teflon atmospheric simulation chamber as part of the Bayreuth ATmospheric simulation CHambers (BATCH) infrastructure. The chamber was irradiated by a bandpass-filtered solar simulator that enabled experiments with realistic photon fluxes and OH radical concentrations. It was coupled to a proton-transfer-reaction time-of-flight mass spectrometer (PTR-ToF-MS) and a solid-phase microextraction–gas chromatography–mass spectrometry (SPME-GC-MS) system for the on-line analysis of the precursor VOC and its oxidation products in the gas phase. As part of the SPME-GC-MS method, multifunctional oxygenated compounds (carbonyls, alcohols, carboxylic acids) were derivatized with O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine (PFBHA) and N-trimethylsilyl-N-methyltrifluoroacetamide (MSTFA). We designed a permeation source for the on-line addition of internal standards to improve method reproducibility. The joint setup was tested and validated by studying the OH-radical-induced photooxidation of toluene, one of the most abundant aromatic hydrocarbons in the atmosphere. For chamber characterization, we first derived the photolysis rates for several typical toluene products in the irradiated BATCH Teflon chamber (1.77 × 10−8–3.02 × 10−4 s−1). Additionally, wall loss rates were determined empirically (4.54 × 10−6–8.53 × 10−5 s−1) and then parameterized according to fundamental molecular properties. For the cresols, we compiled a weighted calibration factor for the PTR-ToF-MS, taking into account isomer-specific sensitivities as well as the relative distribution as determined by the SPME-GC-MS. The weighted calibration improved the instrumental agreement to 14 %, whereas the PTR-ToF-MS overestimated the sum of the isomers by 31 % compared to the SPME-GC-MS concentrations when using the averaged calibration factor. Thus, the combined data set offered insight into both temporal trends and the isomeric composition. Finally, we conducted six toluene photooxidation experiments to evaluate the ring-retaining first-generation products. Based on the loss-corrected concentrations, we derived formation yields for o-cresol (8.0 ± 1.8 %), m-cresol (0.4 ± 0.1 %), p-cresol (2.4 ± 0.6 %), benzyl alcohol (0.5 ± 0.1 %), and benzaldehyde (4.6 ± 1.7 %) under NOx-free conditions at T = 298 ± 1 K. These yields are consistent with previous studies and therefore serve as proof of concept for our applied methods.
{"title":"Characterization of a new Teflon chamber and on-line analysis of isomeric multifunctional photooxidation products","authors":"Finja Löher, Esther Borrás, Amalia Muñoz, Anke Christine Nölscher","doi":"10.5194/amt-17-4553-2024","DOIUrl":"https://doi.org/10.5194/amt-17-4553-2024","url":null,"abstract":"Abstract. The photooxidation of volatile organic compounds (VOCs) in the troposphere has important implications for air quality, weather, and climate. A deeper understanding of the underlying mechanisms can be achieved by studying these reactions under controlled conditions and analysing the emerging photooxidation products. This requires dedicated laboratory infrastructure as well as sensitive and selective analytical techniques. Here, we constructed a new 300 L indoor Teflon atmospheric simulation chamber as part of the Bayreuth ATmospheric simulation CHambers (BATCH) infrastructure. The chamber was irradiated by a bandpass-filtered solar simulator that enabled experiments with realistic photon fluxes and OH radical concentrations. It was coupled to a proton-transfer-reaction time-of-flight mass spectrometer (PTR-ToF-MS) and a solid-phase microextraction–gas chromatography–mass spectrometry (SPME-GC-MS) system for the on-line analysis of the precursor VOC and its oxidation products in the gas phase. As part of the SPME-GC-MS method, multifunctional oxygenated compounds (carbonyls, alcohols, carboxylic acids) were derivatized with O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine (PFBHA) and N-trimethylsilyl-N-methyltrifluoroacetamide (MSTFA). We designed a permeation source for the on-line addition of internal standards to improve method reproducibility. The joint setup was tested and validated by studying the OH-radical-induced photooxidation of toluene, one of the most abundant aromatic hydrocarbons in the atmosphere. For chamber characterization, we first derived the photolysis rates for several typical toluene products in the irradiated BATCH Teflon chamber (1.77 × 10−8–3.02 × 10−4 s−1). Additionally, wall loss rates were determined empirically (4.54 × 10−6–8.53 × 10−5 s−1) and then parameterized according to fundamental molecular properties. For the cresols, we compiled a weighted calibration factor for the PTR-ToF-MS, taking into account isomer-specific sensitivities as well as the relative distribution as determined by the SPME-GC-MS. The weighted calibration improved the instrumental agreement to 14 %, whereas the PTR-ToF-MS overestimated the sum of the isomers by 31 % compared to the SPME-GC-MS concentrations when using the averaged calibration factor. Thus, the combined data set offered insight into both temporal trends and the isomeric composition. Finally, we conducted six toluene photooxidation experiments to evaluate the ring-retaining first-generation products. Based on the loss-corrected concentrations, we derived formation yields for o-cresol (8.0 ± 1.8 %), m-cresol (0.4 ± 0.1 %), p-cresol (2.4 ± 0.6 %), benzyl alcohol (0.5 ± 0.1 %), and benzaldehyde (4.6 ± 1.7 %) under NOx-free conditions at T = 298 ± 1 K. These yields are consistent with previous studies and therefore serve as proof of concept for our applied methods.","PeriodicalId":8619,"journal":{"name":"Atmospheric Measurement Techniques","volume":"76 1","pages":""},"PeriodicalIF":3.8,"publicationDate":"2024-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141863914","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-31DOI: 10.5194/egusphere-2024-2126
Olga Zografou, Christos Kaltsonoudis, Maria Gini, Angeliki Matrali, Elias Panagiotopoulos, Alexandros Lekkas, Dimitris Papanastasiou, Spyros N. Pandis, Konstantinos Eleftheriadis
Abstract. A newly developed charge transfer orthogonal Time-of-Flight Mass Spectrometer (oToF-MS), was deployed for the first time in the field in order to evaluate its ability to perform online real-time measurements of volatile organic compounds (VOCs) for a prolonged time period. The study focused on urban air sampling and targeted a specific range of VOCs, namely: acetone, isoprene, benzene, toluene, and xylene. The measurement campaign took place from May to August 2023 at the suburban area in Athens Greece. The measured VOC level were consistent with those reported in previous summer campaigns suggesting that the instrument did not face any unexpected problems moving from the laboratory to the field. The variability of the measurements of the various VOCs was used to gain insights about their sources. Transportation emissions were a dominant source of the BTX compounds (benzene, toluene and xylene). Acetone and isoprene were emitted by both anthropogenic and biogenic sources. During the summer biogenic sources were responsible for most of the isoprene in the site.
{"title":"Field evaluation of a novel charge transfer ionization TOF MS for ambient VOC measurements","authors":"Olga Zografou, Christos Kaltsonoudis, Maria Gini, Angeliki Matrali, Elias Panagiotopoulos, Alexandros Lekkas, Dimitris Papanastasiou, Spyros N. Pandis, Konstantinos Eleftheriadis","doi":"10.5194/egusphere-2024-2126","DOIUrl":"https://doi.org/10.5194/egusphere-2024-2126","url":null,"abstract":"<strong>Abstract.</strong> A newly developed charge transfer orthogonal Time-of-Flight Mass Spectrometer (oToF-MS), was deployed for the first time in the field in order to evaluate its ability to perform online real-time measurements of volatile organic compounds (VOCs) for a prolonged time period. The study focused on urban air sampling and targeted a specific range of VOCs, namely: acetone, isoprene, benzene, toluene, and xylene. The measurement campaign took place from May to August 2023 at the suburban area in Athens Greece. The measured VOC level were consistent with those reported in previous summer campaigns suggesting that the instrument did not face any unexpected problems moving from the laboratory to the field. The variability of the measurements of the various VOCs was used to gain insights about their sources. Transportation emissions were a dominant source of the BTX compounds (benzene, toluene and xylene). Acetone and isoprene were emitted by both anthropogenic and biogenic sources. During the summer biogenic sources were responsible for most of the isoprene in the site.","PeriodicalId":8619,"journal":{"name":"Atmospheric Measurement Techniques","volume":"44 1","pages":""},"PeriodicalIF":3.8,"publicationDate":"2024-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141864027","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract. Remote hail detection and hail size estimation using weather radar observations has the advantage of wide spatial coverage and high spatial and temporal resolution. Switzerland's National Weather Service (MeteoSwiss) uses two radar-based hail metrics: the probability of hail on the ground (POH) to assess the presence of hail and the maximum expected severe hailstone size (MESHS) to estimate the largest hailstone diameter. However, radar-based metrics are not direct measurements of hail and have to be calibrated with and verified against ground-based observations of hail, such as crowdsourced hail reports. Switzerland benefits from a particularly rich and dense dataset of crowdsourced hail reports from the MeteoSwiss app. We combine a new spatiotemporal clustering method (Density-Based Spatial Clustering of Applications with Noise, ST-DBSCAN) with radar reflectivity to filter the reports and use the filtered reports to verify POH and MESHS in terms of the hit rate, false-alarm ratio (FAR), critical success index (CSI), and Heidke skill score (HSS). Using a 4 km × 4 km maximum upscaling approach, we find FAR values between 0.3 and 0.7 for POH and FAR > 0.6 for MESHS. For POH, the highest CSI (0.37) and HSS (0.52) are obtained using a 60 % threshold, while for MESHS the highest CSI (0.25) and HSS (0.4) are obtained using a 2 cm threshold. We find that the current calibration of POH does not correspond to a probability and suggest a recalibration based on the filtered reports.
{"title":"Verification of weather-radar-based hail metrics with crowdsourced observations from Switzerland","authors":"Jérôme Kopp, Alessandro Hering, Urs Germann, Olivia Martius","doi":"10.5194/amt-17-4529-2024","DOIUrl":"https://doi.org/10.5194/amt-17-4529-2024","url":null,"abstract":"Abstract. Remote hail detection and hail size estimation using weather radar observations has the advantage of wide spatial coverage and high spatial and temporal resolution. Switzerland's National Weather Service (MeteoSwiss) uses two radar-based hail metrics: the probability of hail on the ground (POH) to assess the presence of hail and the maximum expected severe hailstone size (MESHS) to estimate the largest hailstone diameter. However, radar-based metrics are not direct measurements of hail and have to be calibrated with and verified against ground-based observations of hail, such as crowdsourced hail reports. Switzerland benefits from a particularly rich and dense dataset of crowdsourced hail reports from the MeteoSwiss app. We combine a new spatiotemporal clustering method (Density-Based Spatial Clustering of Applications with Noise, ST-DBSCAN) with radar reflectivity to filter the reports and use the filtered reports to verify POH and MESHS in terms of the hit rate, false-alarm ratio (FAR), critical success index (CSI), and Heidke skill score (HSS). Using a 4 km × 4 km maximum upscaling approach, we find FAR values between 0.3 and 0.7 for POH and FAR > 0.6 for MESHS. For POH, the highest CSI (0.37) and HSS (0.52) are obtained using a 60 % threshold, while for MESHS the highest CSI (0.25) and HSS (0.4) are obtained using a 2 cm threshold. We find that the current calibration of POH does not correspond to a probability and suggest a recalibration based on the filtered reports.","PeriodicalId":8619,"journal":{"name":"Atmospheric Measurement Techniques","volume":"194 1","pages":""},"PeriodicalIF":3.8,"publicationDate":"2024-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141864029","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-29DOI: 10.5194/egusphere-2024-1987
Alexander Kelsch, Matthias Claß, Nicolas Brüggemann
Abstract. Regional estimates of ammonia (NH3) emissions are often missing data from heterogeneous or small fields. Areas with no experienced staff or in-field power supply also prevent the use of accurate and fully established micrometeorological measurement techniques. The Dräger Tube Method (DTM) is a calibrated open-dynamic chamber method, which requires little training to use and is comparatively inexpensive. It uses NH3 detector tubes (Dräger Tubes), an automatic pump, as well as a chamber system comprised of four stainless steel chambers connected with PTFE tubing. Even though the DTM is often used in countries such as Germany and China, the detection accuracy, precision and sensitivity have not been tested yet. In order to quantify those for the DTM, we simultaneously measured defined NH3 mixing ratios with the Dräger Tubes, with direct laser absorption spectroscopy (MGA7, MIRO Analytical AG, Switzerland) and with cavity ring-down spectroscopy (G2103, Picarro, Inc., USA). Second, we tested the exchange of the tubing material and heating of the tubing under laboratory conditions, as well as PTFE film attachments or wiping of the DTM chamber system with ethanol during outdoor measurements, on performance improvements. Results showed that the Dräger Tubes had a detection limit between 150 and 200 ppb, which is three to four times higher than originally assumed. Dräger Tube concentration measurements also underestimated NH3 concentrations by 43 up to 100 % for mixing ratios between 50 and 300 ppb, and by 28 up to 46 % for mixing ratios between 500 and 1500 ppb. The PTFE tubing material showed similar performances to the polyester-polyurethane tubing material regarding response time, which was further improved by heating of the tubing to 50 °C. The modifications of the chamber surface and cleaning in the outdoor experiment did not lead to any improvements of NH3 concentration measurements. The results suggest that the DTM should only be used where alternatives are unfeasible and high NH3 emissions are to be expected. A further assessment of calibrated DTM with reference methods is required for a comprehensive evaluation and alternative developments for a more appropriate method replacing the DTM in small plot applications is encouraged.
{"title":"Accuracy and sensitivity of NH3 measurements using the Dräger Tube Method","authors":"Alexander Kelsch, Matthias Claß, Nicolas Brüggemann","doi":"10.5194/egusphere-2024-1987","DOIUrl":"https://doi.org/10.5194/egusphere-2024-1987","url":null,"abstract":"<strong>Abstract.</strong> Regional estimates of ammonia (NH<sub>3</sub>) emissions are often missing data from heterogeneous or small fields. Areas with no experienced staff or in-field power supply also prevent the use of accurate and fully established micrometeorological measurement techniques. The Dräger Tube Method (DTM) is a calibrated open-dynamic chamber method, which requires little training to use and is comparatively inexpensive. It uses NH<sub>3</sub> detector tubes (Dräger Tubes), an automatic pump, as well as a chamber system comprised of four stainless steel chambers connected with PTFE tubing. Even though the DTM is often used in countries such as Germany and China, the detection accuracy, precision and sensitivity have not been tested yet. In order to quantify those for the DTM, we simultaneously measured defined NH<sub>3</sub> mixing ratios with the Dräger Tubes, with direct laser absorption spectroscopy (MGA<sup>7</sup>, MIRO Analytical AG, Switzerland) and with cavity ring-down spectroscopy (G2103, Picarro, Inc., USA). Second, we tested the exchange of the tubing material and heating of the tubing under laboratory conditions, as well as PTFE film attachments or wiping of the DTM chamber system with ethanol during outdoor measurements, on performance improvements. Results showed that the Dräger Tubes had a detection limit between 150 and 200 ppb, which is three to four times higher than originally assumed. Dräger Tube concentration measurements also underestimated NH<sub>3</sub> concentrations by 43 up to 100 % for mixing ratios between 50 and 300 ppb, and by 28 up to 46 % for mixing ratios between 500 and 1500 ppb. The PTFE tubing material showed similar performances to the polyester-polyurethane tubing material regarding response time, which was further improved by heating of the tubing to 50 °C. The modifications of the chamber surface and cleaning in the outdoor experiment did not lead to any improvements of NH<sub>3</sub> concentration measurements. The results suggest that the DTM should only be used where alternatives are unfeasible and high NH<sub>3</sub> emissions are to be expected. A further assessment of calibrated DTM with reference methods is required for a comprehensive evaluation and alternative developments for a more appropriate method replacing the DTM in small plot applications is encouraged.","PeriodicalId":8619,"journal":{"name":"Atmospheric Measurement Techniques","volume":"22 1","pages":""},"PeriodicalIF":3.8,"publicationDate":"2024-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141863917","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-29DOI: 10.5194/amt-17-4507-2024
Karolin Voss, Philip Holzbeck, Klaus Pfeilsticker, Ralph Kleinschek, Gerald Wetzel, Blanca Fuentes Andrade, Michael Höpfner, Jörn Ungermann, Björn-Martin Sinnhuber, André Butz
Abstract. We report on a novel, medium-weight (∼ 25 kg) optical spectrometer coupled to an automated sun tracker for direct sun observations from azimuth-controlled balloon platforms weighing approximately 12 kg. It is designed to measure a suite of UV–Vis absorbing gases relevant in the context of stratospheric ozone depletion using the differential optical absorption spectroscopy (DOAS) method, i.e. O3, NO2, BrO, OClO, HONO, and IO. Here, we describe the design and major features of the instrument. Further, the instrument's performance during two stratospheric deployments from Esrange near Kiruna (Sweden) on 21 August 2021 and from Timmins (Ontario, Canada) on 23 August 2022 is discussed along with the first results concerning inferred mixing ratios of BrO above balloon float altitude. Using a photochemical correction for the partitioning of stratospheric bromine ([BrO]/[Bry]) obtained by chemical transport simulations, the inferred total stratospheric bromine load [Bry] amounts to (17.5 ± 2.2) ppt, with a purely statistical error amounting to 1.5 ppt in (5.5 ± 1.0)-year old air. The latter is inferred from simultaneous measurements of N2O by the GLORIA (Gimballed Limb Observer for Radiance Imaging of the Atmosphere) mid-IR instrument, resulting in a stratospheric entry of the investigated air mass in early 2017 ± 1 year.
{"title":"A novel, balloon-borne UV–Vis spectrometer for direct sun measurements of stratospheric bromine","authors":"Karolin Voss, Philip Holzbeck, Klaus Pfeilsticker, Ralph Kleinschek, Gerald Wetzel, Blanca Fuentes Andrade, Michael Höpfner, Jörn Ungermann, Björn-Martin Sinnhuber, André Butz","doi":"10.5194/amt-17-4507-2024","DOIUrl":"https://doi.org/10.5194/amt-17-4507-2024","url":null,"abstract":"Abstract. We report on a novel, medium-weight (∼ 25 kg) optical spectrometer coupled to an automated sun tracker for direct sun observations from azimuth-controlled balloon platforms weighing approximately 12 kg. It is designed to measure a suite of UV–Vis absorbing gases relevant in the context of stratospheric ozone depletion using the differential optical absorption spectroscopy (DOAS) method, i.e. O3, NO2, BrO, OClO, HONO, and IO. Here, we describe the design and major features of the instrument. Further, the instrument's performance during two stratospheric deployments from Esrange near Kiruna (Sweden) on 21 August 2021 and from Timmins (Ontario, Canada) on 23 August 2022 is discussed along with the first results concerning inferred mixing ratios of BrO above balloon float altitude. Using a photochemical correction for the partitioning of stratospheric bromine ([BrO]/[Bry]) obtained by chemical transport simulations, the inferred total stratospheric bromine load [Bry] amounts to (17.5 ± 2.2) ppt, with a purely statistical error amounting to 1.5 ppt in (5.5 ± 1.0)-year old air. The latter is inferred from simultaneous measurements of N2O by the GLORIA (Gimballed Limb Observer for Radiance Imaging of the Atmosphere) mid-IR instrument, resulting in a stratospheric entry of the investigated air mass in early 2017 ± 1 year.","PeriodicalId":8619,"journal":{"name":"Atmospheric Measurement Techniques","volume":"147 1","pages":""},"PeriodicalIF":3.8,"publicationDate":"2024-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141864030","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-29DOI: 10.5194/amt-17-4493-2024
Johanna Pedersen, Sasha D. Hafner, Andreas Pacholski, Valthor I. Karlsson, Li Rong, Rodrigo Labouriau, Jesper N. Kamp
Abstract. Field-applied liquid animal manure (slurry) is a significant source of ammonia (NH3) emission, which is harmful to the environment and human health. To evaluate mitigation options, reliable emission measurement methods are needed. A new system of dynamic flux chambers (DFCs) with high-temporal-resolution online measurements was developed. The system was investigated in silico with computational fluid dynamics and tested using three respective field trials, with each trial assessing the variability in the measured emission after application with trailing hose at different scales: manual (handheld) application, a 3 m experimental slurry boom, and a 30 m farm-scale commercial slurry boom. For the experiments with machine application, parallel NH3 emission measurements were made using an inverse dispersion modeling method (backward Lagrangian stochastic, bLS, modeling). The lowest coefficient of variation among replicate DFC measurements was obtained with manual application (5 %), followed by the 3 m slurry boom (14 %), and lastly the 30 m slurry boom (20 %). Conditions in DFCs resulted in a consistently higher NH3 flux than that measured with the inverse dispersion technique, but both methods showed a similar emission reduction by injection compared with the trailing hose: 89 % by DFC and 97 % by bLS modeling. The new measurement system facilitates NH3 emission measurement with replication after both manual and farm-scale slurry application with relatively high precision.
{"title":"Evaluation of optimized flux chamber design for measurement of ammonia emission after field application of slurry with full-scale farm machinery","authors":"Johanna Pedersen, Sasha D. Hafner, Andreas Pacholski, Valthor I. Karlsson, Li Rong, Rodrigo Labouriau, Jesper N. Kamp","doi":"10.5194/amt-17-4493-2024","DOIUrl":"https://doi.org/10.5194/amt-17-4493-2024","url":null,"abstract":"Abstract. Field-applied liquid animal manure (slurry) is a significant source of ammonia (NH3) emission, which is harmful to the environment and human health. To evaluate mitigation options, reliable emission measurement methods are needed. A new system of dynamic flux chambers (DFCs) with high-temporal-resolution online measurements was developed. The system was investigated in silico with computational fluid dynamics and tested using three respective field trials, with each trial assessing the variability in the measured emission after application with trailing hose at different scales: manual (handheld) application, a 3 m experimental slurry boom, and a 30 m farm-scale commercial slurry boom. For the experiments with machine application, parallel NH3 emission measurements were made using an inverse dispersion modeling method (backward Lagrangian stochastic, bLS, modeling). The lowest coefficient of variation among replicate DFC measurements was obtained with manual application (5 %), followed by the 3 m slurry boom (14 %), and lastly the 30 m slurry boom (20 %). Conditions in DFCs resulted in a consistently higher NH3 flux than that measured with the inverse dispersion technique, but both methods showed a similar emission reduction by injection compared with the trailing hose: 89 % by DFC and 97 % by bLS modeling. The new measurement system facilitates NH3 emission measurement with replication after both manual and farm-scale slurry application with relatively high precision.","PeriodicalId":8619,"journal":{"name":"Atmospheric Measurement Techniques","volume":"25 1","pages":""},"PeriodicalIF":3.8,"publicationDate":"2024-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141863915","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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