Abstract. Previous work suggests that acoustic waves at frequencies below human hearing (infrasound) are produced during tornadogenesis and continue through the life of a tornado, which have potential to locate and profile tornadic events and provide a range improvement relative to current radar capabilities, which are the current primary measurement tool. Confirming and identifying the fluid mechanism responsible for infrasonic production has been impeded by limited availability and quality (propagation-related uncertainty) of tornadic infrasound data. This paper describes an effort to increase the number of measurements and reduce the uncertainty in subsequent analysis by equipping storm chasers and first responders in regular proximity to tornadoes with mobile infrasound measurement capabilities. The study focus is the design, calibration, deployment, and analysis of data collected by a Ground-based Local INfrasound Data Acquisition (GLINDA) system that collects and relays data from an infrasound microphone, GPS receiver, and an IMU. GLINDA has been deployed with storm chasers beginning in May 2020 and has provided continuing real-time automated monitoring of spectrum and peak detection. In analysis of sampled severe weather phenomena, the signal measured from an EFU tornado (Lakin, KS) show an elevated broadband signal between 10 and 15 Hz. A significant hail event produced no significant increase infrasound signal despite rotation in the storm. The consistency of these observations with existing fixed array measurements and real-time tools to reduce measurement uncertainty demonstrates the value of acquiring tornado infrasound observations from mobile on-location systems and introduces a capability for real-time processing and display of mobile infrasonic measurements.
{"title":"Infrasound measurement system for real-time in-situ tornado measurements","authors":"Brandon C. White, B. Elbing, Imraan A. Faruque","doi":"10.5194/amt-2021-155","DOIUrl":"https://doi.org/10.5194/amt-2021-155","url":null,"abstract":"Abstract. Previous work suggests that acoustic waves at frequencies below human hearing (infrasound) are produced during tornadogenesis and continue through the life of a tornado, which have potential to locate and profile tornadic events and provide a range improvement relative to current radar capabilities, which are the current primary measurement tool. Confirming and identifying the fluid mechanism responsible for infrasonic production has been impeded by limited availability and quality (propagation-related uncertainty) of tornadic infrasound data. This paper describes an effort to increase the number of measurements and reduce the uncertainty in subsequent analysis by equipping storm chasers and first responders in regular proximity to tornadoes with mobile infrasound measurement capabilities. The study focus is the design, calibration, deployment, and analysis of data collected by a Ground-based Local INfrasound Data Acquisition (GLINDA) system that collects and relays data from an infrasound microphone, GPS receiver, and an IMU. GLINDA has been deployed with storm chasers beginning in May 2020 and has provided continuing real-time automated monitoring of spectrum and peak detection. In analysis of sampled severe weather phenomena, the signal measured from an EFU tornado (Lakin, KS) show an elevated broadband signal between 10 and 15 Hz. A significant hail event produced no significant increase infrasound signal despite rotation in the storm. The consistency of these observations with existing fixed array measurements and real-time tools to reduce measurement uncertainty demonstrates the value of acquiring tornado infrasound observations from mobile on-location systems and introduces a capability for real-time processing and display of mobile infrasonic measurements.\u0000","PeriodicalId":441110,"journal":{"name":"Atmospheric Measurement Techniques Discussions","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125689714","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Soo-Hyun Kim, Jeonghoe Kim, Jung‐Hoon Kim, H. Chun
Abstract. The cube root of the energy dissipation rate (EDR), as a standard reporting metric of atmospheric turbulence, is estimated using 1-Hz quick access recorder data from Korean-based national air carriers with two different types of aircraft [Boeing 737 (B737) and B777], archived for 12 months from January to December 2012. Various EDRs are estimated using zonal, meridional, and derived vertical wind components, and the derived equivalent vertical gust (DEVG). Wind-based EDRs are estimated by (i) second-order structure function (EDR1), (ii) power spectral density (PSD), considering the Kolmogorov’s -5/3 dependence (EDR2), and (iii) maximum-likelihood estimation using the von Kármán spectral model (EDR3). DEVG-based EDRs are obtained mainly by vertical acceleration with different conversions to EDR using (iv) the lognormal mapping technique (EDR4) and (v) the predefined parabolic relationship between the observed EDR and DEVG (EDR5). For the EDR1, second-order structure functions are computed for zonal, meridional, and vertical wind within the defined inertial subrange. For the EDR2 and EDR3, individual PSDs for each wind component are computed using the Fast Fourier Transform over every 2-minute time window. Then, two EDR estimates are computed separately by employing the Kolmogorov-scale slope (EDR2) or prescribed von Kármán wind model (EDR3) within the inertial subrange. The resultant EDR estimates from five different methods follow a lognormal distribution reasonably well, which satisfies the fundamental characteristics of atmospheric turbulence. Statistics (mean and standard deviation) of log-scale EDRs are somewhat different from those found in a previous study using a higher frequency (10 Hz) of in situ aircraft data in the United States, likely due to different sampling rates, aircraft types, and locations. Finally, five EDR estimates capture well the intensity and location of three strong turbulence cases that are relevant to clear-air turbulence (CAT), mountain wave turbulence (MWT), and convectively induced turbulence (CIT), with different characteristics of the observed EDRs: 1) zonal (vertical) wind-based EDRs are stronger in the CAT (CIT) case, while MWT has a peak of EDRs in both zonal and vertical wind-based EDRs, and 2) the CAT and MWT cases occurred by large-scale (synoptic-scale) forcing have more variations in EDRs before and after the incident, while the CIT case triggered by smaller mesoscale convective cell has an isolated peak of EDR.
{"title":"Characteristics of the Derived Energy Dissipation Rate using the 1-Hz Commercial Aircraft Quick Access Recorder (QAR) Data","authors":"Soo-Hyun Kim, Jeonghoe Kim, Jung‐Hoon Kim, H. Chun","doi":"10.5194/amt-2021-161","DOIUrl":"https://doi.org/10.5194/amt-2021-161","url":null,"abstract":"Abstract. The cube root of the energy dissipation rate (EDR), as a standard reporting metric of atmospheric turbulence, is estimated using 1-Hz quick access recorder data from Korean-based national air carriers with two different types of aircraft [Boeing 737 (B737) and B777], archived for 12 months from January to December 2012. Various EDRs are estimated using zonal, meridional, and derived vertical wind components, and the derived equivalent vertical gust (DEVG). Wind-based EDRs are estimated by (i) second-order structure function (EDR1), (ii) power spectral density (PSD), considering the Kolmogorov’s -5/3 dependence (EDR2), and (iii) maximum-likelihood estimation using the von Kármán spectral model (EDR3). DEVG-based EDRs are obtained mainly by vertical acceleration with different conversions to EDR using (iv) the lognormal mapping technique (EDR4) and (v) the predefined parabolic relationship between the observed EDR and DEVG (EDR5). For the EDR1, second-order structure functions are computed for zonal, meridional, and vertical wind within the defined inertial subrange. For the EDR2 and EDR3, individual PSDs for each wind component are computed using the Fast Fourier Transform over every 2-minute time window. Then, two EDR estimates are computed separately by employing the Kolmogorov-scale slope (EDR2) or prescribed von Kármán wind model (EDR3) within the inertial subrange. The resultant EDR estimates from five different methods follow a lognormal distribution reasonably well, which satisfies the fundamental characteristics of atmospheric turbulence. Statistics (mean and standard deviation) of log-scale EDRs are somewhat different from those found in a previous study using a higher frequency (10 Hz) of in situ aircraft data in the United States, likely due to different sampling rates, aircraft types, and locations. Finally, five EDR estimates capture well the intensity and location of three strong turbulence cases that are relevant to clear-air turbulence (CAT), mountain wave turbulence (MWT), and convectively induced turbulence (CIT), with different characteristics of the observed EDRs: 1) zonal (vertical) wind-based EDRs are stronger in the CAT (CIT) case, while MWT has a peak of EDRs in both zonal and vertical wind-based EDRs, and 2) the CAT and MWT cases occurred by large-scale (synoptic-scale) forcing have more variations in EDRs before and after the incident, while the CIT case triggered by smaller mesoscale convective cell has an isolated peak of EDR.\u0000","PeriodicalId":441110,"journal":{"name":"Atmospheric Measurement Techniques Discussions","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123942634","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
K. Mróz, A. Battaglia, C. Nguyen, A. Heymsfield, A. Protat, M. Wolde
Abstract. An algorithm based on triple-frequency (X, Ka, W) radar measurements that retrieves the size, water content and degree of riming of ice clouds is presented. This study exploits the potential of multi-frequency radar measurements to provide information on bulk snow density that should underpin better estimates of the snow characteristic size and content within the radar volume. The algorithm is based on Bayes' rule with riming parameterized by the “fill-in” model. The radar reflectivities are simulated with a range of scattering models corresponding to realistic snowflake shapes. The algorithm is tested on multi-frequency radar data collected during the ESA-funded Radar Snow Experiment. During this campaign in-situ microphysical probes were mounted on the same airplane as the radars. This nearly perfectly collocated dataset of the remote and in-situ measurements gives an opportunity to derive a combined multi-instrument estimate of snow microphysical properties that is used for a rigorous validation of the radar retrieval. Results suggest that the triple-frequency retrieval performs well in estimating ice water content and mean-mass-weighted diameters obtaining root-mean-square-error of 0.13 and 0.15, respectively for log10 IWC and log10 Dm. The retrieval of the degree of riming is more challenging and only the algorithm that uses Doppler information obtains results that are highly correlated with the in-situ data.
{"title":"Triple frequency radar retrieval of microphysical properties of snow","authors":"K. Mróz, A. Battaglia, C. Nguyen, A. Heymsfield, A. Protat, M. Wolde","doi":"10.5194/amt-2021-227","DOIUrl":"https://doi.org/10.5194/amt-2021-227","url":null,"abstract":"Abstract. An algorithm based on triple-frequency (X, Ka, W) radar measurements that retrieves the size, water content and degree of riming of ice clouds is presented. This study exploits the potential of multi-frequency radar measurements to provide information on bulk snow density that should underpin better estimates of the snow characteristic size and content within the radar volume. The algorithm is based on Bayes' rule with riming parameterized by the “fill-in” model. The radar reflectivities are simulated with a range of scattering models corresponding to realistic snowflake shapes. The algorithm is tested on multi-frequency radar data collected during the ESA-funded Radar Snow Experiment. During this campaign in-situ microphysical probes were mounted on the same airplane as the radars. This nearly perfectly collocated dataset of the remote and in-situ measurements gives an opportunity to derive a combined multi-instrument estimate of snow microphysical properties that is used for a rigorous validation of the radar retrieval. Results suggest that the triple-frequency retrieval performs well in estimating ice water content and mean-mass-weighted diameters obtaining root-mean-square-error of 0.13 and 0.15, respectively for log10 IWC and log10 Dm. The retrieval of the degree of riming is more challenging and only the algorithm that uses Doppler information obtains results that are highly correlated with the in-situ data.\u0000","PeriodicalId":441110,"journal":{"name":"Atmospheric Measurement Techniques Discussions","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122041097","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract. In the early part of the 20th century, tracking a pilot balloon from the ground with an optical theodolite was one of the few methods that was able to provide information from the upper air. One of the most significant sources of error with this method, however, was involved in calculating the balloon height as a function of time, a calculation dependent on the ascent rate which was traditionally taken to be constant. This study presents a new thermodynamic model which allows us to compute the thermal jump between the surrounding environment and the lifting gas as a function of different parameters such as the atmospheric temperature lapse rate or the physical characteristics of the balloon. The size of the thermal jump and its effect on the ascent rate is discussed for a 30 g pilot balloon, which was the type used at the Ebro Observatory (EO) between 1952 and 1963. The meridional and zonal components of the wind profile from ground level up to 10 km altitude were computed by applying the model using EO digitized data for a sample of this period. The obtained results correlate very well with those obtained from the ERA5 reanalysis. A very small thermal jump with a weak effect on the computed ascent rate was found. This ascent rate is consistent with the values assigned in that period to the balloons filled with hydrogen used at the Ebro Observatory and to the 30 g balloons filled with helium used by the US National Weather Service.
{"title":"Thermodynamic model for a pilot balloon","authors":"Vicent Favà, J. Curto, A. Gilabert","doi":"10.5194/amt-2021-206","DOIUrl":"https://doi.org/10.5194/amt-2021-206","url":null,"abstract":"Abstract. In the early part of the 20th century, tracking a pilot balloon from the ground with an optical theodolite was one of the few methods that was able to provide information from the upper air. One of the most significant sources of error with this method, however, was involved in calculating the balloon height as a function of time, a calculation dependent on the ascent rate which was traditionally taken to be constant. This study presents a new thermodynamic model which allows us to compute the thermal jump between the surrounding environment and the lifting gas as a function of different parameters such as the atmospheric temperature lapse rate or the physical characteristics of the balloon. The size of the thermal jump and its effect on the ascent rate is discussed for a 30 g pilot balloon, which was the type used at the Ebro Observatory (EO) between 1952 and 1963. The meridional and zonal components of the wind profile from ground level up to 10 km altitude were computed by applying the model using EO digitized data for a sample of this period. The obtained results correlate very well with those obtained from the ERA5 reanalysis. A very small thermal jump with a weak effect on the computed ascent rate was found. This ascent rate is consistent with the values assigned in that period to the balloons filled with hydrogen used at the Ebro Observatory and to the 30 g balloons filled with helium used by the US National Weather Service.\u0000","PeriodicalId":441110,"journal":{"name":"Atmospheric Measurement Techniques Discussions","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128985855","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Farhan Mustafa, Lingbing Bu, Qin Wang, Na Yao, Muhammad Shahzaman, M. Bilal, Rana Waqar Aslam, R. Iqbal
Abstract. Atmospheric carbon dioxide (CO2) is the most significant greenhouse gas and its concentration is continuously increasing mainly as a consequence of anthropogenic activities. Accurate quantification of CO2 is critical for addressing the global challenge of climate change and designing mitigation strategies aimed at stabilizing the CO2 emissions. Satellites provide the most effective way to monitor the concentration of CO2 in the atmosphere. In this study, we utilized the concentration of column-averaged dry-air mole fraction of CO2 i.e., XCO2 retrieved from a CO2 monitoring satellite, the Orbiting Carbon Observatory 2 (OCO-2) to estimate the anthropogenic CO2 emissions using Generalized Regression Neural Network over East and West Asia. OCO-2 XCO2 and the Open-Data Inventory for Anthropogenic Carbon dioxide (ODIAC) CO2 emission datasets for a period of 5 years (2015–2019) were used in this study. The annual XCO2 anomalies were calculated from the OCO-2 retrievals for each year to remove the larger background CO2 concentrations and seasonal variabilities. Then the XCO2 anomaly and ODIAC emission datasets from 2015 to 2018 were used to train the GRNN model, and finally, the anthropogenic CO2 emissions were estimated for 2019 based on the XCO2 anomalies derived for the same year. The XCO2-based estimated and the ODIAC actual CO2 emissions were compared and the results showed a good agreement in terms of spatial distribution. The CO2 emissions were estimated separately over East and West Asia. In addition, correlations between the ODIAC emissions and XCO2 anomalies were also determined separately for East and West Asia, and East Asia exhibited relatively better results. The results showed that satellite-based XCO2 retrievals can be used to estimate the regional scale anthropogenic CO2 emissions and the accuracy of the results can be enhanced by further improvement of the GRNN model with the addition of more CO2 emission and concentration datasets.
{"title":"Neural Network Based Estimation of Regional Scale Anthropogenic CO2 Emissions Using OCO-2 Dataset Over East and West Asia","authors":"Farhan Mustafa, Lingbing Bu, Qin Wang, Na Yao, Muhammad Shahzaman, M. Bilal, Rana Waqar Aslam, R. Iqbal","doi":"10.5194/amt-2021-222","DOIUrl":"https://doi.org/10.5194/amt-2021-222","url":null,"abstract":"Abstract. Atmospheric carbon dioxide (CO2) is the most significant greenhouse gas and its concentration is continuously increasing mainly as a consequence of anthropogenic activities. Accurate quantification of CO2 is critical for addressing the global challenge of climate change and designing mitigation strategies aimed at stabilizing the CO2 emissions. Satellites provide the most effective way to monitor the concentration of CO2 in the atmosphere. In this study, we utilized the concentration of column-averaged dry-air mole fraction of CO2 i.e., XCO2 retrieved from a CO2 monitoring satellite, the Orbiting Carbon Observatory 2 (OCO-2) to estimate the anthropogenic CO2 emissions using Generalized Regression Neural Network over East and West Asia. OCO-2 XCO2 and the Open-Data Inventory for Anthropogenic Carbon dioxide (ODIAC) CO2 emission datasets for a period of 5 years (2015–2019) were used in this study. The annual XCO2 anomalies were calculated from the OCO-2 retrievals for each year to remove the larger background CO2 concentrations and seasonal variabilities. Then the XCO2 anomaly and ODIAC emission datasets from 2015 to 2018 were used to train the GRNN model, and finally, the anthropogenic CO2 emissions were estimated for 2019 based on the XCO2 anomalies derived for the same year. The XCO2-based estimated and the ODIAC actual CO2 emissions were compared and the results showed a good agreement in terms of spatial distribution. The CO2 emissions were estimated separately over East and West Asia. In addition, correlations between the ODIAC emissions and XCO2 anomalies were also determined separately for East and West Asia, and East Asia exhibited relatively better results. The results showed that satellite-based XCO2 retrievals can be used to estimate the regional scale anthropogenic CO2 emissions and the accuracy of the results can be enhanced by further improvement of the GRNN model with the addition of more CO2 emission and concentration datasets.","PeriodicalId":441110,"journal":{"name":"Atmospheric Measurement Techniques Discussions","volume":"118 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131040142","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Higashino, M. Hayashi, T. Okada, S. Nagasaki, Koichiro Shiraishi, Keiichi Ozuka
Abstract. The authors have developed a system for the Antarctic stratospheric aerosol observation and sample-return using the combination of a rubber balloon, a parachute, and a gliding fixed-wing unmanned aerial vehicle (UAV). A rubber balloon can usually reach 20 km to 30 km in altitude, but it becomes difficult for the UAV designed as a low-subsonic UAV to directly glide back from the stratospheric altitudes because the quantitative aerodynamic characteristics necessary for the control system design at such altitudes are difficult to obtain. In order to make the observation and sample-return possible at such higher altitudes while avoiding the problem with the control system of the UAV, the method using the two-stage separation was developed and attempted in Antarctica. In two-stage separation method, the UAV first descends by a parachute after separating from the balloon at stratospheric altitude to a certain altitude wherein the flight control system of the UAV works properly. Then it secondly separates the parachute for autonomous gliding back to the released point on the ground. The UAV in which an optical particle counter and an airborne aerosol sampler were installed was launched on January 24, 2015 from S17 (69.028S, 40.093E, 607 m MSL) near Syowa Station in Antarctica. The system reached 23 km in altitude and the UAV successfully returned aerosol samples. In this paper, the details of the UAV system using the two-stage separation method including the observation flight results, and the preliminary results of the observation and analyses of the samples are shown.
摘要作者开发了一种利用橡胶气球、降落伞和滑翔固定翼无人机(UAV)相结合的南极平流层气溶胶观测和样本回收系统。一个橡胶气球通常能达到20公里到30公里的高度，但是对于设计为低亚音速无人机的无人机来说，从平流层高度直接滑翔回来变得困难，因为在这样的高度很难获得控制系统设计所需的定量气动特性。为了避免无人机控制系统的问题，使观测和样本返回在这样的高海拔可能，采用两级分离的方法被开发和尝试在南极洲。在两级分离方法中，无人机在平流层高度与气球分离后，首先通过降落伞下降到一定高度，此时无人机的飞行控制系统工作正常。然后再分离降落伞，使其自动滑翔回到地面上的释放点。搭载光学粒子计数器和机载气溶胶采样器的无人机于2015年1月24日在南极洲Syowa站附近的S17 (69.028S, 40.093E, 607 m MSL)发射。该系统达到了23公里的高度，无人机成功返回了气溶胶样本。本文详细介绍了采用两级分离方法的无人机系统，包括观测飞行结果，以及对样品的初步观测和分析结果。
{"title":"The Antarctic Stratospheric Aerosol Observation and Sample-Return System Using Two-Stage Separation Method of a Balloon-Assisted Unmanned Aerial Vehicle","authors":"S. Higashino, M. Hayashi, T. Okada, S. Nagasaki, Koichiro Shiraishi, Keiichi Ozuka","doi":"10.5194/amt-2021-234","DOIUrl":"https://doi.org/10.5194/amt-2021-234","url":null,"abstract":"Abstract. The authors have developed a system for the Antarctic stratospheric aerosol observation and sample-return using the combination of a rubber balloon, a parachute, and a gliding fixed-wing unmanned aerial vehicle (UAV). A rubber balloon can usually reach 20 km to 30 km in altitude, but it becomes difficult for the UAV designed as a low-subsonic UAV to directly glide back from the stratospheric altitudes because the quantitative aerodynamic characteristics necessary for the control system design at such altitudes are difficult to obtain. In order to make the observation and sample-return possible at such higher altitudes while avoiding the problem with the control system of the UAV, the method using the two-stage separation was developed and attempted in Antarctica. In two-stage separation method, the UAV first descends by a parachute after separating from the balloon at stratospheric altitude to a certain altitude wherein the flight control system of the UAV works properly. Then it secondly separates the parachute for autonomous gliding back to the released point on the ground. The UAV in which an optical particle counter and an airborne aerosol sampler were installed was launched on January 24, 2015 from S17 (69.028S, 40.093E, 607 m MSL) near Syowa Station in Antarctica. The system reached 23 km in altitude and the UAV successfully returned aerosol samples. In this paper, the details of the UAV system using the two-stage separation method including the observation flight results, and the preliminary results of the observation and analyses of the samples are shown.\u0000","PeriodicalId":441110,"journal":{"name":"Atmospheric Measurement Techniques Discussions","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125642232","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract. To correctly understand and interpret lidar acquired signals and to provide high quality data, the characterization of the lidar transmitter-receiver geometry is required. For example, being fundamental to correctly align lidar systems, this characterization is useful to improve the efficiency of the alignment procedure. In addition, some applications (e.g. air quality monitoring) need to quantitatively interpret the observations even in the range where the overlap between the telescope field of view and the laser beam is incomplete. This is generally accomplished by correcting for the overlap function. Within the frame of Lidar based networks (e.g. ACTRIS/EARLINET) there is a need to define standardized approaches to deal with lidar geometry issues. The multi-wavelength multi-telescope Rayleigh-Mie-Raman “9-eyes” system in Rome Tor Vergata, part of ACTRIS/EARLINET, has the capability to change through computer-controlled servomotors, the orientation of the laser beams and the 3D position of the diaphragm of the receiving optical system around the focal point of the telescopes. Taking advantage of these instrumental design characteristics an original approach to characterize the dependency of the acquired signal from the system relative transmitter-receiver geometry (the mapping procedure) was developed. The procedure consists in a set of programs controlling both the signal acquisition as well as the motor movements. The approach includes solutions to account for atmospheric and laser power variability likely to occur during the mapping sessions. The paper describes in detail the developed procedure and applications such as the optimization of the telescope/beam alignment and the estimation of the overlap function. The results of the mapping applied to a single combination of telescope-laser beam are shown and discussed. The effectiveness of the mapping-based alignment was successfully verified by comparing the whole signal profile and the outcome of the telecover test, adopted in EARLINET, for a manual and a mapping-based alignment. A significant signal increase and lowering of the full overlap height (from 1500 m to less than 1000 m) was found. The overlap function was estimated down to 200 m and compared against the one obtained from a geometric model. The developed procedure allowed also estimating the absolute and relative tilt of the laser beam. The mapping approach, even in simplified versions, can be adapted to other lidars to characterize and align systems with non-motorized receiving geometry.
摘要为了正确理解和解释激光雷达采集的信号并提供高质量的数据，需要对激光雷达收发器的几何形状进行表征。例如，作为正确对准激光雷达系统的基础，这种表征有助于提高对准过程的效率。此外，一些应用(例如空气质量监测)需要定量地解释观测结果，即使在望远镜视场和激光束之间的重叠不完全的范围内。这通常是通过校正重叠函数来完成的。在基于激光雷达的网络框架内(例如ACTRIS/EARLINET)，需要定义处理激光雷达几何问题的标准化方法。作为ACTRIS/EARLINET的一部分，Rome Tor Vergata的多波长多望远镜瑞利-米-拉曼“9眼”系统能够通过计算机控制的伺服电机改变激光束的方向和接收光学系统的光圈在望远镜焦点周围的三维位置。利用这些仪器设计特性，开发了一种原始方法来表征来自系统相对发射器-接收器几何形状的采集信号的依赖性(映射程序)。该过程由一组控制信号采集和电机运动的程序组成。该方法包括解决在绘图过程中可能发生的大气和激光功率变化。本文详细介绍了该方法的开发过程及其在望远镜/光束对准优化、重叠函数估计等方面的应用。给出了单次望远镜-激光束组合的映射结果，并进行了讨论。通过比较EARLINET中采用的手动和基于映射的对准的整个信号剖面和远程测试结果，成功验证了基于映射的对准的有效性。发现全重叠高度(从1500 m到1000 m以下)有显著的信号增加和降低。估计了200 m的重叠函数，并与几何模型得到的重叠函数进行了比较。所开发的程序还允许估计激光束的绝对和相对倾斜。即使是简化版本的测绘方法，也可以适用于其他激光雷达，以表征和对齐非机动接收几何形状的系统。
{"title":"A semi-automated procedure for the emitter-receiver geometry characterization of motor-controlled lidars","authors":"Marco Di Paolantonio, D. Dionisi, G. Liberti","doi":"10.5194/amt-2021-231","DOIUrl":"https://doi.org/10.5194/amt-2021-231","url":null,"abstract":"Abstract. To correctly understand and interpret lidar acquired signals and to provide high quality data, the characterization of the lidar transmitter-receiver geometry is required. For example, being fundamental to correctly align lidar systems, this characterization is useful to improve the efficiency of the alignment procedure. In addition, some applications (e.g. air quality monitoring) need to quantitatively interpret the observations even in the range where the overlap between the telescope field of view and the laser beam is incomplete. This is generally accomplished by correcting for the overlap function. Within the frame of Lidar based networks (e.g. ACTRIS/EARLINET) there is a need to define standardized approaches to deal with lidar geometry issues. The multi-wavelength multi-telescope Rayleigh-Mie-Raman “9-eyes” system in Rome Tor Vergata, part of ACTRIS/EARLINET, has the capability to change through computer-controlled servomotors, the orientation of the laser beams and the 3D position of the diaphragm of the receiving optical system around the focal point of the telescopes. Taking advantage of these instrumental design characteristics an original approach to characterize the dependency of the acquired signal from the system relative transmitter-receiver geometry (the mapping procedure) was developed. The procedure consists in a set of programs controlling both the signal acquisition as well as the motor movements. The approach includes solutions to account for atmospheric and laser power variability likely to occur during the mapping sessions. The paper describes in detail the developed procedure and applications such as the optimization of the telescope/beam alignment and the estimation of the overlap function. The results of the mapping applied to a single combination of telescope-laser beam are shown and discussed. The effectiveness of the mapping-based alignment was successfully verified by comparing the whole signal profile and the outcome of the telecover test, adopted in EARLINET, for a manual and a mapping-based alignment. A significant signal increase and lowering of the full overlap height (from 1500 m to less than 1000 m) was found. The overlap function was estimated down to 200 m and compared against the one obtained from a geometric model. The developed procedure allowed also estimating the absolute and relative tilt of the laser beam. The mapping approach, even in simplified versions, can be adapted to other lidars to characterize and align systems with non-motorized receiving geometry.\u0000","PeriodicalId":441110,"journal":{"name":"Atmospheric Measurement Techniques Discussions","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132244923","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Wengang Zhang, Ling Wang, Yang Yu, Guirong Xu, Xiuqing Hu, Zhikang Fu, C. Cui
Abstract. The evaluation of precipitable water vapor (PWV) derived from the advanced Medium Resolution Spectral Imager (MERSI-II) onboard FengYun-3D is performed with the PWV from Integrated Global Radiosonde Archive (IGRA) based on 626 sites (54214 match-ups) in total during 2018–2021. The averaged PWVs from MERSI-II and IGRA both present the distribution opposite to latitude, with great PWV mostly found in the tropics. In general, a good consistency exists between the PWVs of MERSI-Ⅱ and IGRA, and their correlation coefficient is 0.9400 and root mean squared error (RMSE) is 0.31 cm. The peak values of mean bias (MB) and the mean relative bias (MRB) are 0.00 cm and −2.38 %, with the standard deviations of 0.25 cm and 16.8 %, respectively. For most sites, the PWV is underestimated with the MB between −0.28 cm and 0.05 cm. However, there is also overestimated PWV, which is mostly distributed in the surrounding areas of the Black Sea and the middle of South America. The peak values of MB are found in February and July over the Southern and Northern Hemisphere, respectively. More than 66.91 % of retrievals falling within the except error (EE) envelope during all months. Overall, the MRB and RMSE become larger with the increasing temporal and distance discrepancy, and it is contrast for EE and correlation coefficient. Besides, the distance discrepancy impacts the evaluation more. The application of PWV product over Qinghai-Tibet Plateau shows that the transport of water vapor along the Brahmaputra Grand Canyon is obvious and it is more significant in July.
摘要利用2018-2021年全球综合无线电探空档案(IGRA)的先进中分辨率光谱成像仪(MERSI-II)对2018-2021年间626个站点(54214个配对)的可降水量(PWV)进行评估。MERSI-II和IGRA的平均PWV均呈反纬度分布，较大的PWV多出现在热带地区。总体而言，MERSI-Ⅱ与IGRA的pwv具有较好的一致性，其相关系数为0.9400，均方根误差(RMSE)为0.31 cm。平均偏置(MB)和平均相对偏置(MRB)的峰值分别为0.00 cm和- 2.38%，标准差分别为0.25 cm和16.8%。对于大多数站点，PWV被低估，MB在- 0.28 cm ~ 0.05 cm之间。然而，也有高估的PWV，主要分布在黑海周边地区和南美洲中部。MB峰值分别出现在南半球的2月和北半球的7月。在所有月份中，超过66.91%的检索结果落在除错误(EE)范围内。总体而言，MRB和RMSE随时间和距离差异的增加而增大，而情感表达和相关系数则相反。此外，距离差异对评价的影响更大。PWV产品在青藏高原的应用表明，沿雅鲁藏布江大峡谷的水汽输送明显，且在7月更为显著。
{"title":"Evaluation and Application of Precipitable Water Vapor Product from MERSI-II onboard the Fengyun-3D Satellite","authors":"Wengang Zhang, Ling Wang, Yang Yu, Guirong Xu, Xiuqing Hu, Zhikang Fu, C. Cui","doi":"10.5194/amt-2021-236","DOIUrl":"https://doi.org/10.5194/amt-2021-236","url":null,"abstract":"Abstract. The evaluation of precipitable water vapor (PWV) derived from the advanced Medium Resolution Spectral Imager (MERSI-II) onboard FengYun-3D is performed with the PWV from Integrated Global Radiosonde Archive (IGRA) based on 626 sites (54214 match-ups) in total during 2018–2021. The averaged PWVs from MERSI-II and IGRA both present the distribution opposite to latitude, with great PWV mostly found in the tropics. In general, a good consistency exists between the PWVs of MERSI-Ⅱ and IGRA, and their correlation coefficient is 0.9400 and root mean squared error (RMSE) is 0.31 cm. The peak values of mean bias (MB) and the mean relative bias (MRB) are 0.00 cm and −2.38 %, with the standard deviations of 0.25 cm and 16.8 %, respectively. For most sites, the PWV is underestimated with the MB between −0.28 cm and 0.05 cm. However, there is also overestimated PWV, which is mostly distributed in the surrounding areas of the Black Sea and the middle of South America. The peak values of MB are found in February and July over the Southern and Northern Hemisphere, respectively. More than 66.91 % of retrievals falling within the except error (EE) envelope during all months. Overall, the MRB and RMSE become larger with the increasing temporal and distance discrepancy, and it is contrast for EE and correlation coefficient. Besides, the distance discrepancy impacts the evaluation more. The application of PWV product over Qinghai-Tibet Plateau shows that the transport of water vapor along the Brahmaputra Grand Canyon is obvious and it is more significant in July.\u0000","PeriodicalId":441110,"journal":{"name":"Atmospheric Measurement Techniques Discussions","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127053693","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hengheng Zhang, F. Wagner, H. Saathoff, H. Vogel, G. Hoshyaripour, V. Bachmann, J. Förstner, T. Leisner
Abstract. The evolution and the properties of a Saharan dust plume were studied near the city of Karlsruhe in south-west Germany (8.4298° E, 49.0953° N) from April 7 to 9, 2018 combining a scanning LIDAR (90°, 30°), a vertical LIDAR (90°), a sun photometer, and the transport model ICON-ART. The LIDAR measurements show that the dust particles had backscatter coefficients of 0.86 ± 0.14 Mm−1 Sr−1, an extinction coefficient of 40 ± 0.8 Mm−1, a LIDAR ratio of 46 ± 5 sr, and a particle depolarization ratio of 0.33 ± 0.07. These values are in good agreement with those obtained in previous studies of Saharan dust plumes in Western Europe. Compared to the remote sensing measurements, the model simulation predicts the plume arrival time, its layer height, and structure very well but overestimates the backscatter coefficient. In this manuscript, we discuss the complementarity and advantages of the different measurement methods as well model simulations to predict Saharan dust plumes. Main conclusions are that the ICON-ART model can predict the structure of Saharan dust plumes very well but overestimates the backscatter coefficients by a factor of 2.2 ± 0.16 at 355 nm and underestimates the aerosol optical depth (AOD) by a factor of 1.5 ± 0.11 at 340 nm for this Saharan dust plume event. Employing a scanning aerosol LIDAR allows determining backscatter coefficient, particle depolarization ratio and especially LIDAR ratio of Saharan dust both for daytime and nighttime independently. Combining LIDAR with sun photometer data allows constraining aerosol optical depth in different ways and determining column integrated LIDAR ratios. These comprehensive datasets allow for a better understanding of Saharan dust plumes in Western Europe.
{"title":"Investigation of a Saharan dust plume in Western Europe by remote sensing and transport modelling","authors":"Hengheng Zhang, F. Wagner, H. Saathoff, H. Vogel, G. Hoshyaripour, V. Bachmann, J. Förstner, T. Leisner","doi":"10.5194/amt-2021-193","DOIUrl":"https://doi.org/10.5194/amt-2021-193","url":null,"abstract":"Abstract. The evolution and the properties of a Saharan dust plume were studied near the city of Karlsruhe in south-west Germany (8.4298° E, 49.0953° N) from April 7 to 9, 2018 combining a scanning LIDAR (90°, 30°), a vertical LIDAR (90°), a sun photometer, and the transport model ICON-ART. The LIDAR measurements show that the dust particles had backscatter coefficients of 0.86 ± 0.14 Mm−1 Sr−1, an extinction coefficient of 40 ± 0.8 Mm−1, a LIDAR ratio of 46 ± 5 sr, and a particle depolarization ratio of 0.33 ± 0.07. These values are in good agreement with those obtained in previous studies of Saharan dust plumes in Western Europe. Compared to the remote sensing measurements, the model simulation predicts the plume arrival time, its layer height, and structure very well but overestimates the backscatter coefficient. In this manuscript, we discuss the complementarity and advantages of the different measurement methods as well model simulations to predict Saharan dust plumes. Main conclusions are that the ICON-ART model can predict the structure of Saharan dust plumes very well but overestimates the backscatter coefficients by a factor of 2.2 ± 0.16 at 355 nm and underestimates the aerosol optical depth (AOD) by a factor of 1.5 ± 0.11 at 340 nm for this Saharan dust plume event. Employing a scanning aerosol LIDAR allows determining backscatter coefficient, particle depolarization ratio and especially LIDAR ratio of Saharan dust both for daytime and nighttime independently. Combining LIDAR with sun photometer data allows constraining aerosol optical depth in different ways and determining column integrated LIDAR ratios. These comprehensive datasets allow for a better understanding of Saharan dust plumes in Western Europe.\u0000","PeriodicalId":441110,"journal":{"name":"Atmospheric Measurement Techniques Discussions","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125518762","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Chunshui Lin, D. Ceburnis, Anna Trubetskaya, Wei Xu, William Smith, S. Hellebust, J. Wenger, C. O’Dowd, J. Ovadnevaitė
Abstract. Reference mass spectra are routinely used to facilitate source apportionment of ambient organic aerosol (OA) measured by an aerosol chemical speciation monitor (ACSM). However. source apportionment of solid fuel burning emissions can be complicated by the use of different fuels, stoves and burning conditions. In this study, the organic aerosol mass spectra produced from burning a range of solid fuels in several stoves have been compared using an ACSM. The same samples of biomass briquettes and smokeless coal were burnt in a conventional and Ecodesign stove, while different batches of wood, peat, and smoky coal were also burnt in the conventional stove and the OA mass spectra compared to those previously obtained using a boiler stove. The results shows that although certain ions (e.g., m/z 60) remain important markers for solid fuel burning, the peak intensities obtained at specific m/z values were not constant with variations ranging from <5% to >100 %. Using the OA mass spectra of peat, wood and coal as anchoring profiles and the variation of individual m/z values for the upper/lower limits in ME-2 analysis (the limits approach), the respective contributions of these fuels to ambient sub-micron aerosols during a winter period in Dublin were evaluated and compared with the conventional a value approach. The ME-2 solution was stable for the limits approach with uncertainties in the range of 2–7 %, while relatively large uncertainties (8–29 %) were found for the a value approach. Nevertheless, both approaches showed good agreement overall, with the burning of peat (39 % vs 41 %) and wood (14 % vs 11 %) accounting for the majority of ambient organic aerosol during polluted evenings, despite their small uses. This study, thus, accounts for the source variability in ME-2 modelling and provides better constraints on the primary factor contributions to the ambient organic aerosol estimations. The finding from this study has significant implications for public health and policymakers considering that it is often the case that different batches of solid fuels are often burned in different stoves in real-world applications.
{"title":"On the use of reference mass spectra for reducing uncertainty in source apportionment of solid fuel burning in ambient organic aerosol","authors":"Chunshui Lin, D. Ceburnis, Anna Trubetskaya, Wei Xu, William Smith, S. Hellebust, J. Wenger, C. O’Dowd, J. Ovadnevaitė","doi":"10.5194/amt-2021-174","DOIUrl":"https://doi.org/10.5194/amt-2021-174","url":null,"abstract":"Abstract. Reference mass spectra are routinely used to facilitate source apportionment of ambient organic aerosol (OA) measured by an aerosol chemical speciation monitor (ACSM). However. source apportionment of solid fuel burning emissions can be complicated by the use of different fuels, stoves and burning conditions. In this study, the organic aerosol mass spectra produced from burning a range of solid fuels in several stoves have been compared using an ACSM. The same samples of biomass briquettes and smokeless coal were burnt in a conventional and Ecodesign stove, while different batches of wood, peat, and smoky coal were also burnt in the conventional stove and the OA mass spectra compared to those previously obtained using a boiler stove. The results shows that although certain ions (e.g., m/z 60) remain important markers for solid fuel burning, the peak intensities obtained at specific m/z values were not constant with variations ranging from <5% to >100 %. Using the OA mass spectra of peat, wood and coal as anchoring profiles and the variation of individual m/z values for the upper/lower limits in ME-2 analysis (the limits approach), the respective contributions of these fuels to ambient sub-micron aerosols during a winter period in Dublin were evaluated and compared with the conventional a value approach. The ME-2 solution was stable for the limits approach with uncertainties in the range of 2–7 %, while relatively large uncertainties (8–29 %) were found for the a value approach. Nevertheless, both approaches showed good agreement overall, with the burning of peat (39 % vs 41 %) and wood (14 % vs 11 %) accounting for the majority of ambient organic aerosol during polluted evenings, despite their small uses. This study, thus, accounts for the source variability in ME-2 modelling and provides better constraints on the primary factor contributions to the ambient organic aerosol estimations. The finding from this study has significant implications for public health and policymakers considering that it is often the case that different batches of solid fuels are often burned in different stoves in real-world applications.\u0000","PeriodicalId":441110,"journal":{"name":"Atmospheric Measurement Techniques Discussions","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132700462","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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