Pub Date : 2024-08-09DOI: 10.5194/egusphere-2024-2482
Nagendra Raparthi, Anthony S. Wexler, Ann M. Dillner
Abstract. Due to US regulations, concentrations of hygroscopic inorganic sulfate and nitrate have declined in recent years, leading to an increased importance in the hygroscopic nature of organic matter (OM). The hygroscopicity of OM is poorly characterized because only a fraction of the multitude of organic compounds in the atmosphere are readily measured and there is limited information on their hygroscopic behaviours. Hygroscopicity of aerosol is traditionally measured using Humidified Tandem Differential Mobility Analyzer (HTDMA) or Electrodynamic Balance (EDB). EDB measures water uptake by a single particle. For ambient and chamber studies, HTDMA measurements provide water uptake and particle size information but not chemical composition. To fill in this information gap, we have developed a novel methodology to assess the water uptake of particle collected on Teflon filters, thereby providing an opportunity to link the measured hygroscopicity with ambient particle composition. To test the method, hygroscopic measurements were conducted in the laboratory for ammonium sulfate, sodium chloride, glucose, and malonic acid, which were collected on 25 mm Teflon filters using an aerosol generator and sampler. Constant humidity solutions (CHS) were employed to maintain the relative humidity (RH) at approximately 84 %, 90 %, and 97 % in small chambers. Hygroscopic parameters, including the water-to-solute (W/S) ratio, molality, mass fraction solute (mfs), and growth factors (GF), were calculated from the measurements. The results obtained are consistent with those reported by the E-AIM model and previous studies utilizing HTDMA and EDB for these compounds, highlighting the accuracy of this new methodology. This new approach enables the hygroscopicity and chemical composition of individual filter samples to be assessed so that in complex mixtures such as chamber and ambient samples, the total water uptake can be parsed between the inorganic and organic components of the aerosol.
{"title":"A Novel Methodology for Assessing the Hygroscopicity of Aerosol Filter Samples","authors":"Nagendra Raparthi, Anthony S. Wexler, Ann M. Dillner","doi":"10.5194/egusphere-2024-2482","DOIUrl":"https://doi.org/10.5194/egusphere-2024-2482","url":null,"abstract":"<strong>Abstract.</strong> Due to US regulations, concentrations of hygroscopic inorganic sulfate and nitrate have declined in recent years, leading to an increased importance in the hygroscopic nature of organic matter (OM). The hygroscopicity of OM is poorly characterized because only a fraction of the multitude of organic compounds in the atmosphere are readily measured and there is limited information on their hygroscopic behaviours. Hygroscopicity of aerosol is traditionally measured using Humidified Tandem Differential Mobility Analyzer (HTDMA) or Electrodynamic Balance (EDB). EDB measures water uptake by a single particle. For ambient and chamber studies, HTDMA measurements provide water uptake and particle size information but not chemical composition. To fill in this information gap, we have developed a novel methodology to assess the water uptake of particle collected on Teflon filters, thereby providing an opportunity to link the measured hygroscopicity with ambient particle composition. To test the method, hygroscopic measurements were conducted in the laboratory for ammonium sulfate, sodium chloride, glucose, and malonic acid, which were collected on 25 mm Teflon filters using an aerosol generator and sampler. Constant humidity solutions (CHS) were employed to maintain the relative humidity (RH) at approximately 84 %, 90 %, and 97 % in small chambers. Hygroscopic parameters, including the water-to-solute (W/S) ratio, molality, mass fraction solute (mfs), and growth factors (GF), were calculated from the measurements. The results obtained are consistent with those reported by the E-AIM model and previous studies utilizing HTDMA and EDB for these compounds, highlighting the accuracy of this new methodology. This new approach enables the hygroscopicity and chemical composition of individual filter samples to be assessed so that in complex mixtures such as chamber and ambient samples, the total water uptake can be parsed between the inorganic and organic components of the aerosol.","PeriodicalId":8619,"journal":{"name":"Atmospheric Measurement Techniques","volume":"94 1","pages":""},"PeriodicalIF":3.8,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141939570","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}
Ivonne Trebs, Céline Lett, Andreas Krein, Erika Matsumoto Kawaguchi, Jürgen Junk
Abstract. Knowledge of the chemical composition of particulate matter (PM) is essential for understanding its source distribution, identifying potential health impacts of toxic elements and to develop efficient air pollution abatement strategies. Traditional methods for analysing PM composition, such as collection on filter substrates and subsequent offline analysis with e.g., inductively coupled plasma mass spectrometry (ICP-MS), are time-consuming and prone to measurement errors due to multiple preparation steps. Emerging near-real time techniques based on non-destructive Energy Dispersive X-ray Fluorescence (EDXRF) offer advantages for continuous monitoring and source apportionment. This study characterises the Horiba PX-375 EDXRF monitor by applying a straightforward performance evaluation including (a) limit of detection (LoD), (b) identification and quantification of uncertainty sources, and (c) investigating and comparing measurement results from three contrasting sites in Luxembourg (urban, semi-urban, rural). We used multi-element reference materials (ME-RMs) from UC Davis for calibration and performed measurements during spring and summer 2023. The LoDs for toxic elements like Ni, Cu, Zn, and Pb were below 3 ng m-3 at one-hour time resolution. Higher LoDs were observed for lighter elements (e.g., Al, Si, S, K, Ca). Expanded uncertainties ranged between 5 and 25 % for elemental concentrations above 20 ng m-3 and were maximal for concentrations below 10 ng m-3, reaching 60–85 %. Elemental analysis revealed S and mineral elements (Fe, Si, Ca, Al) as dominant contributors to PM10. Toxic elements (As, Ni, Pb) were often below the LoD, suggesting minimal exposure risk in the sampled areas. Our results explained on average 51–74 % of the gravimetric PM10 mass at the three sites. The study highlights the suitability and importance of the continuous PX-375 particle monitor for future air quality monitoring and source apportionment studies, particularly under changing emission scenarios and air pollution abatement strategies.
{"title":"Performance evaluation of an online monitor based on X-ray fluorescence for detecting elemental concentrations in ambient particulate matter","authors":"Ivonne Trebs, Céline Lett, Andreas Krein, Erika Matsumoto Kawaguchi, Jürgen Junk","doi":"10.5194/amt-2024-134","DOIUrl":"https://doi.org/10.5194/amt-2024-134","url":null,"abstract":"<strong>Abstract.</strong> Knowledge of the chemical composition of particulate matter (PM) is essential for understanding its source distribution, identifying potential health impacts of toxic elements and to develop efficient air pollution abatement strategies. Traditional methods for analysing PM composition, such as collection on filter substrates and subsequent offline analysis with e.g., inductively coupled plasma mass spectrometry (ICP-MS), are time-consuming and prone to measurement errors due to multiple preparation steps. Emerging near-real time techniques based on non-destructive Energy Dispersive X-ray Fluorescence (EDXRF) offer advantages for continuous monitoring and source apportionment. This study characterises the Horiba PX-375 EDXRF monitor by applying a straightforward performance evaluation including (a) limit of detection (LoD), (b) identification and quantification of uncertainty sources, and (c) investigating and comparing measurement results from three contrasting sites in Luxembourg (urban, semi-urban, rural). We used multi-element reference materials (ME-RMs) from UC Davis for calibration and performed measurements during spring and summer 2023. The LoDs for toxic elements like Ni, Cu, Zn, and Pb were below 3 ng m<sup>-3</sup> at one-hour time resolution. Higher LoDs were observed for lighter elements (e.g., Al, Si, S, K, Ca). Expanded uncertainties ranged between 5 and 25 % for elemental concentrations above 20 ng m<sup>-3</sup> and were maximal for concentrations below 10 ng m<sup>-3</sup>, reaching 60–85 %. Elemental analysis revealed S and mineral elements (Fe, Si, Ca, Al) as dominant contributors to PM10. Toxic elements (As, Ni, Pb) were often below the LoD, suggesting minimal exposure risk in the sampled areas. Our results explained on average 51–74 % of the gravimetric PM10 mass at the three sites. The study highlights the suitability and importance of the continuous PX-375 particle monitor for future air quality monitoring and source apportionment studies, particularly under changing emission scenarios and air pollution abatement strategies.","PeriodicalId":8619,"journal":{"name":"Atmospheric Measurement Techniques","volume":"19 1","pages":""},"PeriodicalIF":3.8,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141939571","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. In situ measurements of water vapour isotopic composition in polar regions has provided needed constrains of post-deposition processes involved in the archiving of the climatic signal in ice core records. During polar winter, the temperatures, and thus the specific humidity, are so low that current commercial techniques are not able to measure the vapour isotopic composition with enough precision. Here, we make use of new developments in infrared spectroscopy and combine an optical-feedback frequency-stabilised laser source (OFFS technique) using a V-shaped cavity optical feedback (VCOF) cavity and a high-finesse cavity ring-down spectroscopy (CRDS) cavity to increase the signal-to-noise ratio while measuring absorption transitions of water isotopes. We present a laboratory infrared spectrometer leveraging all these techniques dedicated to measure water vapour isotopic composition at low humidity levels. At 400 ppmv, the instrument demonstrates a precision of 0.01 ‰ and 0.1 ‰ in δ18O and d-excess, respectively, for an integration time of 2 min. This set-up yields an isotopic composition precision below 1 ‰ at water mixing ratios down to 4 ppmv, which suggests an extrapolated precision in δ18O of 1.5 ‰ at 1 ppmv. Indeed, thanks to the stabilisation of the laser by the VCOF, the instrument exhibits extremely low drift and very high signal-to-noise ratio. The instrument is not hindered by a strong isotope–humidity response which at low humidity can create extensive biases on commercial instruments.
{"title":"Reliable water vapour isotopic composition measurements at low humidity using frequency-stabilised cavity ring-down spectroscopy","authors":"Mathieu Casado, Amaelle Landais, Tim Stoltmann, Justin Chaillot, Mathieu Daëron, Fréderic Prié, Baptiste Bordet, Samir Kassi","doi":"10.5194/amt-17-4599-2024","DOIUrl":"https://doi.org/10.5194/amt-17-4599-2024","url":null,"abstract":"Abstract. In situ measurements of water vapour isotopic composition in polar regions has provided needed constrains of post-deposition processes involved in the archiving of the climatic signal in ice core records. During polar winter, the temperatures, and thus the specific humidity, are so low that current commercial techniques are not able to measure the vapour isotopic composition with enough precision. Here, we make use of new developments in infrared spectroscopy and combine an optical-feedback frequency-stabilised laser source (OFFS technique) using a V-shaped cavity optical feedback (VCOF) cavity and a high-finesse cavity ring-down spectroscopy (CRDS) cavity to increase the signal-to-noise ratio while measuring absorption transitions of water isotopes. We present a laboratory infrared spectrometer leveraging all these techniques dedicated to measure water vapour isotopic composition at low humidity levels. At 400 ppmv, the instrument demonstrates a precision of 0.01 ‰ and 0.1 ‰ in δ18O and d-excess, respectively, for an integration time of 2 min. This set-up yields an isotopic composition precision below 1 ‰ at water mixing ratios down to 4 ppmv, which suggests an extrapolated precision in δ18O of 1.5 ‰ at 1 ppmv. Indeed, thanks to the stabilisation of the laser by the VCOF, the instrument exhibits extremely low drift and very high signal-to-noise ratio. The instrument is not hindered by a strong isotope–humidity response which at low humidity can create extensive biases on commercial instruments.","PeriodicalId":8619,"journal":{"name":"Atmospheric Measurement Techniques","volume":"54 1","pages":""},"PeriodicalIF":3.8,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141939549","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 : 2024-08-07DOI: 10.5194/egusphere-2024-2419
Sanjeevani Panditharatne, Helen Brindley, Caroline Cox, Richard Siddans, Jonathan Murray, Laura Warwick, Stuart Fox
Abstract. We present the extension of the RAL Infrared Microwave Sounding optimal estimation retrieval scheme to include the use of far-infrared channels in preparation for the upcoming Far-infrared Outgoing Radiation Understanding and Monitoring (FORUM) mission. The evolution and evaluation of the extended scheme is performed in two steps. First, clear-sky retrievals of temperature and water vapour are performed on IASI and FORUM simulations. Improvements of 2 % and 0.2 K are observed in the median mid to upper tropospheric retrievals of water vapour and temperature, respectively, using the FORUM configuration, with an increase of ~ 1 degree of freedom for water vapour and temperature. Secondly, radiances observed from an aircraft flight in the upper troposphere are modified to match the FORUM spectral characteristics. Retrievals from these radiances using the modified code show a strong agreement with contemporaneous in-situ measurements of the atmospheric state, reducing the RMSE by 18 % for water vapour from the a-priori, giving confidence in its performance. This tool is now readily available for use on FORUM observations and can be easily adapted to other far and mid-infrared instrument configurations.
摘要。我们介绍了 RAL 红外微波探测最优估计检索方案的扩展，包括远红外信道的使用，为即将到来的远红外出射辐射理解和监测（FORUM）任务做准备。扩展方案的演变和评估分两步进行。首先，对 IASI 和 FORUM 模拟进行温度和水蒸气的晴空检索。使用 FORUM 配置，对流层中上层的水蒸气和温度的中值检索分别提高了 2%和 0.2 K，水蒸气和温度的自由度增加了约 1 个。其次，对飞机在对流层上部飞行时观测到的辐射进行了修改，以符合 FORUM 的光谱特征。使用修改后的代码对这些辐射进行的检索显示，与当时的大气状态现场测量结果非常吻合，水蒸气的均方根误差比先验值降低了 18%，使人们对其性能充满信心。该工具现在可随时用于 FORUM 观测，并可方便地适用于其他远红外和中红外仪器配置。
{"title":"Retrievals of water vapour and temperature exploiting the far-infrared: application to aircraft observations in preparation for the FORUM mission","authors":"Sanjeevani Panditharatne, Helen Brindley, Caroline Cox, Richard Siddans, Jonathan Murray, Laura Warwick, Stuart Fox","doi":"10.5194/egusphere-2024-2419","DOIUrl":"https://doi.org/10.5194/egusphere-2024-2419","url":null,"abstract":"<strong>Abstract.</strong> We present the extension of the RAL Infrared Microwave Sounding optimal estimation retrieval scheme to include the use of far-infrared channels in preparation for the upcoming Far-infrared Outgoing Radiation Understanding and Monitoring (FORUM) mission. The evolution and evaluation of the extended scheme is performed in two steps. First, clear-sky retrievals of temperature and water vapour are performed on IASI and FORUM simulations. Improvements of 2 % and 0.2 K are observed in the median mid to upper tropospheric retrievals of water vapour and temperature, respectively, using the FORUM configuration, with an increase of ~ 1 degree of freedom for water vapour and temperature. Secondly, radiances observed from an aircraft flight in the upper troposphere are modified to match the FORUM spectral characteristics. Retrievals from these radiances using the modified code show a strong agreement with contemporaneous in-situ measurements of the atmospheric state, reducing the RMSE by 18 % for water vapour from the a-priori, giving confidence in its performance. This tool is now readily available for use on FORUM observations and can be easily adapted to other far and mid-infrared instrument configurations.","PeriodicalId":8619,"journal":{"name":"Atmospheric Measurement Techniques","volume":"1 1","pages":""},"PeriodicalIF":3.8,"publicationDate":"2024-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141939428","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 : 2024-08-07DOI: 10.5194/egusphere-2024-2236
Maitane Iturrate-Garcia, Thérèse Salameh, Paul Schlauri, Annarita Baldan, Martin K. Vollmer, Evdokia Stratigou, Sebastian Dusanter, Jianrong Li, Stefan Persijn, Anja Claude, Rupert Holzinger, Christophe Sutour, Tatiana Macé, Yasin Elshorbany, Andreas Ackermann, Céline Pascale, Stefan Reimann
<strong>Abstract.</strong> Volatile organic compounds (VOCs) have a large impact on the oxidising capacity of the troposphere and are major precursors of tropospheric ozone and secondary atmospheric aerosols. Accurate measurements and data comparability of VOCs among monitoring networks are essential to assess the trends of these secondary air pollutants. Metrological traceability of the measurements to the international system of units (SI-traceability) contributes to both: measurement consistency and data comparability. Accurate, stable and SI-traceable reference gas mixtures (RGMs) and working standards are needed to achieve SI-traceability through an unbroken chain of calibrations of the analytical instruments used to monitor VOCs. However, for many oxygenated VOCs (OVOCs), such RGMs and working standards are not available at atmospheric amount of substance fraction levels (< 10 nmol mol<sup>-1</sup>). Here, we present the protocols developed to transfer SI-traceability to the field by producing two types of SI-traceable working standards for selected OVOCs. These working standards, based on RGMs diluted dynamically with dry nitrogen and on certified spiked whole air samples, were then assessed using Thermal Desorption-Gas Chromatography-Flame Ionization Detector (TD-GC-FID) and Proton Transfer Reaction-Time of Flight-Mass Spectrometry (PTR-ToF-MS) as analytical methods. For that purpose, we calibrated five analytical instruments using in-house calibration standards and treated the new SI-traceable working standards as samples. Due to analytical limitations, the assessment was only possible for acetaldehyde, acetone, methanol and methyl ethyl ketone (MEK). Relative differences between assigned and measured values were used to assess the working standards based on dilution of RGMs. The relative differences were within the measurement uncertainty for acetone, MEK, methanol and acetaldehyde at amount of substance fractions around 10 nmol mol<sup>-1</sup>. For the working standards based on certified spiked whole air samples in pressurized cylinders, results showed a good agreement among the laboratories (i.e., differences within the measurement expanded uncertainties (U) ranging between 0.5 nmol mol<sup>-1 </sup>and 3.3 nmol mol<sup>-1</sup>) and with the certified amount of substance fraction value for acetaldehyde (15.7 nmol mol<sup>-1</sup> ± 3.6 (U) nmol mol<sup>-1</sup>), acetone (17 nmol mol<sup>-1 </sup>± 1.5 (U) nmol mol<sup>-1</sup>) and MEK (12.3 nmol mol<sup>-1 </sup>± 2.3 (U) nmol mol<sup>-1</sup>). Despite the promising results for the working standards based on the dilution of RGMs and on certified spiked whole air samples filled into pressurized cylinders, the assessment must be considered with care due to the large measurement uncertainty, particularly for methanol. Active collaboration among metrological, meteorological and atmospheric chemistry monitoring communities is needed to tackle the challenges of OVOC monitoring, suc
摘要挥发性有机化合物（VOCs）对对流层的氧化能力有很大影响，是对流层臭氧和二次大气气溶胶的主要前体物。要评估这些二次空气污染物的趋势，就必须对各监测网络中的挥发性有机化合物进行精确测量并使数据具有可比性。按照国际单位制（SI-可追溯性）进行测量的计量可追溯性有助于实现测量的一致性和数据的可比性。通过对用于监测挥发性有机化合物的分析仪器进行不间断的校准链，实现 SI 可追溯性需要准确、稳定和 SI 可追溯的参考混合气体 (RGM) 和工作标准。然而，对于许多含氧挥发性有机化合物 (OVOC) 而言，在大气物质分数水平（< 10 nmol mol-1）上无法获得此类 RGM 和工作标准。在此，我们介绍了为将 SI 可追溯性转移到现场而开发的协议，为选定的 OVOC 生产了两种类型的 SI 可追溯工作标准。这些工作标准基于用干氮动态稀释的 RGM 和经过认证的加标整个空气样本，然后使用热脱附-气相色谱-火焰离子化检测器（TD-GC-FID）和质子传递反应-飞行时间质谱法（PTR-ToF-MS）作为分析方法进行评估。为此，我们使用内部校准标准校准了五台分析仪器，并将新的 SI 可追溯工作标准作为样品处理。由于分析能力有限，我们只能对乙醛、丙酮、甲醇和甲乙酮 (MEK) 进行评估。分配值和测量值之间的相对差异被用来评估基于稀释 RGM 的工作标准。丙酮、MEK、甲醇和乙醛的物质分数在 10 nmol mol-1 左右时，相对差值在测量不确定范围内。对于基于加压钢瓶中经认证的加标整个空气样本的工作标准，结果显示各实验室之间的一致性很好（即、乙醛（15.7 nmol mol-1 ± 3.6 (U) nmol mol-1）、丙酮（17 nmol mol-1 ± 1.5 (U) nmol mol-1）和甲基安息香酸（12.3 nmol mol-1 ± 2.3 (U) nmol mol-1）的测量结果与经认证的物质分量值一致。尽管基于 RGMs 稀释的工作标准和注入加压钢瓶的经认证的加标整个空气样本的结果很好，但由于测量不确定性较大，尤其是甲醇的测量不确定性较大，因此必须谨慎考虑评估。计量、气象和大气化学监测界需要积极合作，以应对 OVOC 监测所面临的挑战，例如缺乏稳定和 SI 可追溯的校准标准（即 RGM 和工作标准）。除此合作外，其他研究应用，如建模和遥感，也可从监测站的 SI 可追溯性转移中受益。
{"title":"Towards a high quality in-situ observation network for oxygenated volatile organic compounds (OVOCs) in Europe: transferring traceability to the International System of Units (SI) to the field","authors":"Maitane Iturrate-Garcia, Thérèse Salameh, Paul Schlauri, Annarita Baldan, Martin K. Vollmer, Evdokia Stratigou, Sebastian Dusanter, Jianrong Li, Stefan Persijn, Anja Claude, Rupert Holzinger, Christophe Sutour, Tatiana Macé, Yasin Elshorbany, Andreas Ackermann, Céline Pascale, Stefan Reimann","doi":"10.5194/egusphere-2024-2236","DOIUrl":"https://doi.org/10.5194/egusphere-2024-2236","url":null,"abstract":"<strong>Abstract.</strong> Volatile organic compounds (VOCs) have a large impact on the oxidising capacity of the troposphere and are major precursors of tropospheric ozone and secondary atmospheric aerosols. Accurate measurements and data comparability of VOCs among monitoring networks are essential to assess the trends of these secondary air pollutants. Metrological traceability of the measurements to the international system of units (SI-traceability) contributes to both: measurement consistency and data comparability. Accurate, stable and SI-traceable reference gas mixtures (RGMs) and working standards are needed to achieve SI-traceability through an unbroken chain of calibrations of the analytical instruments used to monitor VOCs. However, for many oxygenated VOCs (OVOCs), such RGMs and working standards are not available at atmospheric amount of substance fraction levels (< 10 nmol mol<sup>-1</sup>). Here, we present the protocols developed to transfer SI-traceability to the field by producing two types of SI-traceable working standards for selected OVOCs. These working standards, based on RGMs diluted dynamically with dry nitrogen and on certified spiked whole air samples, were then assessed using Thermal Desorption-Gas Chromatography-Flame Ionization Detector (TD-GC-FID) and Proton Transfer Reaction-Time of Flight-Mass Spectrometry (PTR-ToF-MS) as analytical methods. For that purpose, we calibrated five analytical instruments using in-house calibration standards and treated the new SI-traceable working standards as samples. Due to analytical limitations, the assessment was only possible for acetaldehyde, acetone, methanol and methyl ethyl ketone (MEK). Relative differences between assigned and measured values were used to assess the working standards based on dilution of RGMs. The relative differences were within the measurement uncertainty for acetone, MEK, methanol and acetaldehyde at amount of substance fractions around 10 nmol mol<sup>-1</sup>. For the working standards based on certified spiked whole air samples in pressurized cylinders, results showed a good agreement among the laboratories (i.e., differences within the measurement expanded uncertainties (U) ranging between 0.5 nmol mol<sup>-1 </sup>and 3.3 nmol mol<sup>-1</sup>) and with the certified amount of substance fraction value for acetaldehyde (15.7 nmol mol<sup>-1</sup> ± 3.6 (U) nmol mol<sup>-1</sup>), acetone (17 nmol mol<sup>-1 </sup>± 1.5 (U) nmol mol<sup>-1</sup>) and MEK (12.3 nmol mol<sup>-1 </sup>± 2.3 (U) nmol mol<sup>-1</sup>). Despite the promising results for the working standards based on the dilution of RGMs and on certified spiked whole air samples filled into pressurized cylinders, the assessment must be considered with care due to the large measurement uncertainty, particularly for methanol. Active collaboration among metrological, meteorological and atmospheric chemistry monitoring communities is needed to tackle the challenges of OVOC monitoring, suc","PeriodicalId":8619,"journal":{"name":"Atmospheric Measurement Techniques","volume":"198 1","pages":""},"PeriodicalIF":3.8,"publicationDate":"2024-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141939578","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 : 2024-08-06DOI: 10.5194/egusphere-2024-2198
Oliver G. A. Driver, Marc E. J. Stettler, Edward Gryspeerdt
Abstract. Contrails (clouds produced by aircraft exhaust) have a significant warming contribution to the overall climate impact of aviation. This makes reducing them a key target for future climate strategies in the sector. Identifying pathways for contrail reduction requires accurate models of contrail formation and lifecycle, which in turn need suitable observations to constrain them. Infrared imagers on geostationary satellites provide widespread, time-resolved observations of the evolution of contrail properties. However, contrails are often narrow and optically thin, which makes them challenging for satellites to identify. Quantifying the impact of contrail properties on observability is essential to determine the extent to which satellite observations can be used to constrain contrail models and to assess the climate impact of aviation. In this work, contrail observability is tested by applying a simple contrail detection algorithm to synthetic images of contrails in an otherwise-clear sky against a homogeneous ocean background. Only (46 ± 2) % of a modelled population of global contrail segments are found to be observable using current 2 km resolution instruments, even in this maximally-observable case. A significantly higher portion of contrail forcing is detectable using the same imager—(82 ± 2) % of instantaneous longwave forcing—because observable contrails have a larger climate impact. This detection efficiency could be partly improved by using a higher-resolution infrared imager, which would also allow contrails to be detected earlier in their lifecycle. However, even this instrument would still miss the large fraction of contrails that are too optically thin to be detected. These results support the use of contrail detection and lifetime observations from existing satellite imagers to draw conclusions about the relative radiative importance of different contrails under near-ideal conditions. However, there is a highlighted need to assess the observability of specific contrails depending on the observation requirements of a given application. These observability factors are shown to change in response to climate action, demonstrating a need to consider the properties of the observing system when assessing the impacts of proposed mitigation strategies.
{"title":"Factors limiting contrail detection in satellite imagery","authors":"Oliver G. A. Driver, Marc E. J. Stettler, Edward Gryspeerdt","doi":"10.5194/egusphere-2024-2198","DOIUrl":"https://doi.org/10.5194/egusphere-2024-2198","url":null,"abstract":"<strong>Abstract.</strong> Contrails (clouds produced by aircraft exhaust) have a significant warming contribution to the overall climate impact of aviation. This makes reducing them a key target for future climate strategies in the sector. Identifying pathways for contrail reduction requires accurate models of contrail formation and lifecycle, which in turn need suitable observations to constrain them. Infrared imagers on geostationary satellites provide widespread, time-resolved observations of the evolution of contrail properties. However, contrails are often narrow and optically thin, which makes them challenging for satellites to identify. Quantifying the impact of contrail properties on observability is essential to determine the extent to which satellite observations can be used to constrain contrail models and to assess the climate impact of aviation. In this work, contrail observability is tested by applying a simple contrail detection algorithm to synthetic images of contrails in an otherwise-clear sky against a homogeneous ocean background. Only (46 ± 2) % of a modelled population of global contrail segments are found to be observable using current 2 km resolution instruments, even in this maximally-observable case. A significantly higher portion of contrail forcing is detectable using the same imager—(82 ± 2) % of instantaneous longwave forcing—because observable contrails have a larger climate impact. This detection efficiency could be partly improved by using a higher-resolution infrared imager, which would also allow contrails to be detected earlier in their lifecycle. However, even this instrument would still miss the large fraction of contrails that are too optically thin to be detected. These results support the use of contrail detection and lifetime observations from existing satellite imagers to draw conclusions about the relative radiative importance of different contrails under near-ideal conditions. However, there is a highlighted need to assess the observability of specific contrails depending on the observation requirements of a given application. These observability factors are shown to change in response to climate action, demonstrating a need to consider the properties of the observing system when assessing the impacts of proposed mitigation strategies.","PeriodicalId":8619,"journal":{"name":"Atmospheric Measurement Techniques","volume":"94 1","pages":""},"PeriodicalIF":3.8,"publicationDate":"2024-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141939545","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}
Bing Cao, Jennifer S. Haase, Michael J. Murphy Jr., Anna M. Wilson
Abstract. Atmospheric Rivers (ARs) are narrow filaments of high moisture flux responsible for most of the horizontal transport of water vapor from the tropics to mid-latitudes. Improving forecasts of ARs through numerical weather prediction (NWP) is important for increasing the resilience of the western US to flooding and droughts. These NWP forecasts rely on the improved understanding of AR physics and dynamics from satellite, radar, aircraft, and in situ observations, and now airborne radio occultation (ARO) can contribute to those goals. The ARO technique is based on precise measurements of Global Navigation Satellite Systems (GNSS) signal delays collected from a receiver onboard an aircraft from setting or rising GNSS satellites. ARO inherits the advantages of high vertical resolution and all-weather capability of spaceborne RO observations and has the additional advantage of continuous and dense sampling of the targeted storm area. This work presents a comprehensive ARO dataset recovered from four years of AR Reconnaissance (AR Recon) missions over the eastern Pacific. The final dataset is comprised of ∼ 1700 ARO profiles from 39 flights (∼ 260 flight hours) from multiple GNSS constellations. Profiles extend from aircraft cruising altitude (13–14 km) down into the lower troposphere, with more than 50 % of the profiles extending below 4 km, below which the receiver loses or cannot initiate lock. The horizontal drift of the tangent points that comprise a given ARO profile greatly extends the area sampled from just underneath the aircraft to both sides of the flight track (up to ∼ 400 km). The estimated refractivity accuracy with respect to dropsondes is ∼ 1.2 %, in the upper troposphere where the sample points are closely collocated. For the lower troposphere, the agreement is within ∼ 7 % which is the level of consistency expected given the nature of atmospheric variations over the 300–700 km separation between the lowest point and the dropsonde.
摘要大气河（ARs）是高水汽通量的狭窄细丝，负责从热带到中纬度的大部分水汽水平输送。通过数值天气预报 (NWP) 改进对 AR 的预报对于提高美国西部抵御洪水和干旱的能力非常重要。这些 NWP 预报依赖于卫星、雷达、飞机和现场观测对 AR 物理和动力学的进一步了解，现在机载无线电掩星（ARO）可以为实现这些目标做出贡献。机载无线电掩星技术基于对全球导航卫星系统（GNSS）信号延迟的精确测量，该信号延迟是通过飞机上的接收器从正在下降或上升的 GNSS 卫星上收集的。ARO 继承了机载 RO 观测的高垂直分辨率和全天候能力的优点，并具有对目标风暴区进行连续和密集采样的额外优势。这项工作展示了四年来在东太平洋上空执行的AR侦察（AR Recon）任务所恢复的综合ARO数据集。最终数据集由来自多个全球导航卫星系统星座的 39 次飞行（260 个飞行小时）的 1700 个 ARO 剖面图组成。剖面图从飞机巡航高度（13-14 千米）一直延伸到对流层下部，50% 以上的剖面图延伸到 4 千米以下，在 4 千米以下接收器失去或无法启动锁定。构成特定 ARO 剖面的切点的水平漂移大大扩展了采样区域，从飞机下方一直延伸到飞行轨迹两侧（最远可达 400 千米）。在对流层上部，采样点的位置非常接近，因此与滴度计相比，折射率的估计精度为 1.2%。在对流层下部，鉴于最低点与滴度计之间 300-700 千米距离内大气变化的性质，预期的一致性水平在 7%以内。
{"title":"Observing atmospheric rivers using multi-GNSS airborne radio occultation: system description and data evaluation","authors":"Bing Cao, Jennifer S. Haase, Michael J. Murphy Jr., Anna M. Wilson","doi":"10.5194/amt-2024-119","DOIUrl":"https://doi.org/10.5194/amt-2024-119","url":null,"abstract":"<strong>Abstract.</strong> Atmospheric Rivers (ARs) are narrow filaments of high moisture flux responsible for most of the horizontal transport of water vapor from the tropics to mid-latitudes. Improving forecasts of ARs through numerical weather prediction (NWP) is important for increasing the resilience of the western US to flooding and droughts. These NWP forecasts rely on the improved understanding of AR physics and dynamics from satellite, radar, aircraft, and in situ observations, and now airborne radio occultation (ARO) can contribute to those goals. The ARO technique is based on precise measurements of Global Navigation Satellite Systems (GNSS) signal delays collected from a receiver onboard an aircraft from setting or rising GNSS satellites. ARO inherits the advantages of high vertical resolution and all-weather capability of spaceborne RO observations and has the additional advantage of continuous and dense sampling of the targeted storm area. This work presents a comprehensive ARO dataset recovered from four years of AR Reconnaissance (AR Recon) missions over the eastern Pacific. The final dataset is comprised of ∼ 1700 ARO profiles from 39 flights (∼ 260 flight hours) from multiple GNSS constellations. Profiles extend from aircraft cruising altitude (13–14 km) down into the lower troposphere, with more than 50 % of the profiles extending below 4 km, below which the receiver loses or cannot initiate lock. The horizontal drift of the tangent points that comprise a given ARO profile greatly extends the area sampled from just underneath the aircraft to both sides of the flight track (up to ∼ 400 km). The estimated refractivity accuracy with respect to dropsondes is ∼ 1.2 %, in the upper troposphere where the sample points are closely collocated. For the lower troposphere, the agreement is within ∼ 7 % which is the level of consistency expected given the nature of atmospheric variations over the 300–700 km separation between the lowest point and the dropsonde.","PeriodicalId":8619,"journal":{"name":"Atmospheric Measurement Techniques","volume":"22 1","pages":""},"PeriodicalIF":3.8,"publicationDate":"2024-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141939429","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. We develop the Japan Aerospace Exploration Agency (JAXA) level 2 cloud mask and cloud type classification algorithms for the Earth Clouds, Aerosols, and Radiation Explorer (EarthCARE), a joint JAXA and European Space Agency (ESA) satellite mission. Cloud profiling radar (CPR)-only, atmospheric lidar (ATLID)-only, and combined CPR–ATLID algorithms for the cloud mask and cloud particle type are described. The algorithms are developed and evaluated using ground-based data, space-borne data from CloudSat and Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) and simulation data from a Japanese global cloud-resolving model, the Non-hydrostatic Icosahedral Atmospheric Model (NICAM) with Joint simulator. The algorithms are based on our algorithms for CloudSat and CALIPSO with several improvements. The cloud particle type for ATLID is derived from an attenuation–depolarization diagram trained using 355 nm multiple-field-of-view multiple-scattering polarization lidar and changing the diagram from that developed for CALIPSO. The retrieved cloud particle phases (ice, water, and mixed phases) and those reported in the NICAM output data are compared. We found that the agreement for CPR-only, ATLID-only, and combined CPR–ATLID algorithms averaged roughly 80 %, 85 %, and 80 %, respectively, for 15 different cloud scenes corresponding to two EarthCARE orbits.
{"title":"Cloud masks and cloud type classification using EarthCARE CPR and ATLID","authors":"Hajime Okamoto, Kaori Sato, Tomoaki Nishizawa, Yoshitaka Jin, Shota Ogawa, Hiroshi Ishimoto, Yuichiro Hagihara, EIji Oikawa, Maki Kikuchi, Masaki Satoh, Wooosub Roh","doi":"10.5194/amt-2024-103","DOIUrl":"https://doi.org/10.5194/amt-2024-103","url":null,"abstract":"<strong>Abstract.</strong> We develop the Japan Aerospace Exploration Agency (JAXA) level 2 cloud mask and cloud type classification algorithms for the Earth Clouds, Aerosols, and Radiation Explorer (EarthCARE), a joint JAXA and European Space Agency (ESA) satellite mission. Cloud profiling radar (CPR)-only, atmospheric lidar (ATLID)-only, and combined CPR–ATLID algorithms for the cloud mask and cloud particle type are described. The algorithms are developed and evaluated using ground-based data, space-borne data from CloudSat and Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) and simulation data from a Japanese global cloud-resolving model, the Non-hydrostatic Icosahedral Atmospheric Model (NICAM) with Joint simulator. The algorithms are based on our algorithms for CloudSat and CALIPSO with several improvements. The cloud particle type for ATLID is derived from an attenuation–depolarization diagram trained using 355 nm multiple-field-of-view multiple-scattering polarization lidar and changing the diagram from that developed for CALIPSO. The retrieved cloud particle phases (ice, water, and mixed phases) and those reported in the NICAM output data are compared. We found that the agreement for CPR-only, ATLID-only, and combined CPR–ATLID algorithms averaged roughly 80 %, 85 %, and 80 %, respectively, for 15 different cloud scenes corresponding to two EarthCARE orbits.","PeriodicalId":8619,"journal":{"name":"Atmospheric Measurement Techniques","volume":"8 1","pages":""},"PeriodicalIF":3.8,"publicationDate":"2024-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141939547","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. The Southern Ocean (SO) provides a unique natural laboratory for studying cloud formation and cloud-aerosol interactions with minimal anthropogenic influence. The Southern Ocean Clouds, Radiation, Aerosol Transport Experimental Study (SOCRATES), was an aircraft-based campaign conducted from January 15 to February 28, 2018, off the coast of Hobart, Tasmania. During SOCRATES, the NSF/NCAR GV research aircraft, equipped with in-situ probes and remote sensors, observed aerosol, cloud, and precipitation properties, and provided detailed vertical structure of clouds over the SO, particularly for the low-level clouds (below 3 km). The HIAPER Cloud Radar (HCR) and in-situ cloud and drizzle probes (CDP and 2DS) measurements were used to provide comprehensive statistical and phase-relevant macrophysical properties for the low-level clouds sampled by the 15 research flights during SOCRATES. A new method based on HCR reflectivity and spectrum width gradient was developed to estimate cloud boundaries (cloud-base and -top heights) and classify cloud types based on their top and base heights. Low-level clouds were found to be the most prevalent, with an almost 90 % occurrence frequency. A new phase determination method was also developed to identify the single-layered low-level clouds as liquid, ice, and mixed phases, with occurrence frequencies of 45.4 %, 32.5 %, and 22.2 %, respectively. Low-level clouds over the SO have significantly higher SLW concentrations, with liquid being most prevalent at higher temperatures, ice phase dominating at lower temperatures, and mixed-phase being least common due to its thermodynamic instability. Regarding their vertical distributions, the liquid phase occurs most frequently in the lower mid-cloud range (from 500 m to 1 km), the mixed phase dominates at cloud bases lower than 1 km but is well distributed along the vertical cloud layer, while the ice phase is prevalent from the middle to upper cloud levels (1–3 km). The higher occurrence of the mixed phase at the cloud base could be attributed to large drizzle-sized drops and/or ice particles.
{"title":"Cloud phase estimation and macrophysical properties of low-level clouds using in-situ and radar measurements over the Southern Ocean during the SOCRATES campaign","authors":"Anik Das, Baike Xi, Xiaojian Zheng, Xiquan Dong","doi":"10.5194/amt-2024-124","DOIUrl":"https://doi.org/10.5194/amt-2024-124","url":null,"abstract":"<strong>Abstract.</strong> The Southern Ocean (SO) provides a unique natural laboratory for studying cloud formation and cloud-aerosol interactions with minimal anthropogenic influence. The Southern Ocean Clouds, Radiation, Aerosol Transport Experimental Study (SOCRATES), was an aircraft-based campaign conducted from January 15 to February 28, 2018, off the coast of Hobart, Tasmania. During SOCRATES, the NSF/NCAR GV research aircraft, equipped with in-situ probes and remote sensors, observed aerosol, cloud, and precipitation properties, and provided detailed vertical structure of clouds over the SO, particularly for the low-level clouds (below 3 km). The HIAPER Cloud Radar (HCR) and in-situ cloud and drizzle probes (CDP and 2DS) measurements were used to provide comprehensive statistical and phase-relevant macrophysical properties for the low-level clouds sampled by the 15 research flights during SOCRATES. A new method based on HCR reflectivity and spectrum width gradient was developed to estimate cloud boundaries (cloud-base and -top heights) and classify cloud types based on their top and base heights. Low-level clouds were found to be the most prevalent, with an almost 90 % occurrence frequency. A new phase determination method was also developed to identify the single-layered low-level clouds as liquid, ice, and mixed phases, with occurrence frequencies of 45.4 %, 32.5 %, and 22.2 %, respectively. Low-level clouds over the SO have significantly higher SLW concentrations, with liquid being most prevalent at higher temperatures, ice phase dominating at lower temperatures, and mixed-phase being least common due to its thermodynamic instability. Regarding their vertical distributions, the liquid phase occurs most frequently in the lower mid-cloud range (from 500 m to 1 km), the mixed phase dominates at cloud bases lower than 1 km but is well distributed along the vertical cloud layer, while the ice phase is prevalent from the middle to upper cloud levels (1–3 km). The higher occurrence of the mixed phase at the cloud base could be attributed to large drizzle-sized drops and/or ice particles.","PeriodicalId":8619,"journal":{"name":"Atmospheric Measurement Techniques","volume":"21 1","pages":""},"PeriodicalIF":3.8,"publicationDate":"2024-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141939546","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. The initial weather measurements from two polarimetric phased array radars (PPAR) with cylindrical and planar configurations, both developed by the Advanced Radar Research Center (ARRC) at the University of Oklahoma (OU), were compared with those from the dish-antenna systems, the operational KTLX Weather Surveillance Radar-1988 Doppler (WSR-88D) located in Oklahoma City, Oklahoma (~23 km northeast of OU). Both the cylindrical PPAR (CPPAR) and the planar PPAR (PPPAR) in Horus are S-band two-dimensional (2D) electronic scan PPAR. This comparison investigates the error statistics of the polarimetric measurements in one-dimensional (1D) electronic scan from each radar during two convective rain events. The first event occurred on 30 August 2019, when the CPPAR performed a 3.3° elevation plan-position indicator (PPI) scan at 25 azimuth angles. The second event took place on 4 October 2023, when Horus conducted range-height indicator (RHI) scans at 64 elevations. For both events, KTLX provided volumetric polarimetric radar data and served as the reference. To ensure temporal and spatial alignment between the radars, reconstructed RHI scans and PPI sectors from KTLX were matched to the corresponding Horus rays and CPPAR domain, respectively. The standard deviations and mean biases of the PPAR weather measurements were calculated and analyzed. The standard deviations of the two PPARs were similar and met the Radar Functional Requirements set by the National Oceanic and Atmospheric Administration/National Weather Service. However, as noted in previous studies, the standard deviation, and biases of polarimetric variables from Horus exhibited varying error characteristics depending on the electronic steering angle from broadside. The present results suggest that PPPARs may have difficulties in producing high-quality polarimetric data at large steering angles and further investigation on both CPPAR and 2D PPPAR is required to find the optimal design for future weather applications.
{"title":"Quantitative Error Analysis on Polarimetric Phased Array Radar Weather Measurements to Reveal Radar Performance and Configuration Potential","authors":"Junho Ho, Zhe Li, Guifu Zhang","doi":"10.5194/amt-2024-118","DOIUrl":"https://doi.org/10.5194/amt-2024-118","url":null,"abstract":"<strong>Abstract.</strong> The initial weather measurements from two polarimetric phased array radars (PPAR) with cylindrical and planar configurations, both developed by the Advanced Radar Research Center (ARRC) at the University of Oklahoma (OU), were compared with those from the dish-antenna systems, the operational KTLX Weather Surveillance Radar-1988 Doppler (WSR-88D) located in Oklahoma City, Oklahoma (~23 km northeast of OU). Both the cylindrical PPAR (CPPAR) and the planar PPAR (PPPAR) in Horus are S-band two-dimensional (2D) electronic scan PPAR. This comparison investigates the error statistics of the polarimetric measurements in one-dimensional (1D) electronic scan from each radar during two convective rain events. The first event occurred on 30 August 2019, when the CPPAR performed a 3.3° elevation plan-position indicator (PPI) scan at 25 azimuth angles. The second event took place on 4 October 2023, when Horus conducted range-height indicator (RHI) scans at 64 elevations. For both events, KTLX provided volumetric polarimetric radar data and served as the reference. To ensure temporal and spatial alignment between the radars, reconstructed RHI scans and PPI sectors from KTLX were matched to the corresponding Horus rays and CPPAR domain, respectively. The standard deviations and mean biases of the PPAR weather measurements were calculated and analyzed. The standard deviations of the two PPARs were similar and met the Radar Functional Requirements set by the National Oceanic and Atmospheric Administration/National Weather Service. However, as noted in previous studies, the standard deviation, and biases of polarimetric variables from Horus exhibited varying error characteristics depending on the electronic steering angle from broadside. The present results suggest that PPPARs may have difficulties in producing high-quality polarimetric data at large steering angles and further investigation on both CPPAR and 2D PPPAR is required to find the optimal design for future weather applications.","PeriodicalId":8619,"journal":{"name":"Atmospheric Measurement Techniques","volume":"120 1","pages":""},"PeriodicalIF":3.8,"publicationDate":"2024-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141881400","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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