Atmos. Meas. techniques

Derivation of depolarization ratios of aerosol fluorescence and water vapor Raman backscatters from lidar measurements
Igor Veselovskii, Qiaoyun Hu, Philippe Goloub, Thierry Podvin, William Boissiere, Mikhail Korenskiy, Nikita Kasianik, Sergey Khaykyn, and Robin Miri
Atmos. Meas. Tech., 17, 1023–1036, https://doi.org/10.5194/amt-17-1023-2024, 2024
Measurements of transported smoke layers were performed with a lidar in Lille and a five-channel fluorescence lidar in Moscow. Results show the peak of fluorescence in the boundary layer is at 438 nm, while in the smoke layer it shifts to longer wavelengths. The fluorescence depolarization is 45 % to 55 %. The depolarization ratio of the water vapor channel is low (2 ± 0.5 %) in the absence of fluorescence and can be used to evaluate the contribution of fluorescence to water vapor signal.

Retrieval and analysis of the composition of an aerosol mixture through Mie-Raman-Fluorescence lidar observations
Igor Veselovskii, Boris Barchunov, Qiaoyun Hu, Philippe Goloub, Thierry Podvin, Mikhail Korenskii, Gaël Dubois, William Boissiere, and Nikita Kasianik
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2024-17,2024
Preprint under review for AMT (discussion: open, 0 comments)
The paper presents a new method that categorizes atmospheric aerosols by analyzing their optical properties with a Mie-Raman-fluorescence lidar. The research specifically looks into understanding the presence of smoke, urban, and dust aerosols in the mixtures identified by this lidar. The reliability of the results is evaluated using the Monte Carlo technique. The effectiveness of this approach is successfully demonstrated through testing in ATOLL, an observatory influenced by diverse aerosols.

Improved RepVGG ground-based cloud image classification with attention convolution
Chaojun Shi, Leile Han, Ke Zhang, Hongyin Xiang, Xingkuan Li, Zibo Su, and Xian Zheng
Atmos. Meas. Tech., 17, 979–997, https://doi.org/10.5194/amt-17-979-2024, 2024
This article mainly studies the problem of ground cloud classification and significantly improves the accuracy of ground cloud classification by applying an improved deep-learning method. The research results show that the method proposed in this article has a significant impact on the classification results of ground cloud images. These conclusions have important implications for providing new insights and future research directions in the field of ground cloud classification.

Artificial intelligence (AI)-derived 3D cloud tomography from geostationary 2D satellite data
Sarah Brüning, Stefan Niebler, and Holger Tost
Atmos. Meas. Tech., 17, 961–978, https://doi.org/10.5194/amt-17-961-2024, 2024
We apply the Res-UNet to derive a comprehensive 3D cloud tomography from 2D satellite data over heterogeneous landscapes. We combine observational data from passive and active remote sensing sensors by an automated matching algorithm. These data are fed into a neural network to predict cloud reflectivities on the whole satellite domain between 2.4 and 24 km height. With an average RMSE of 2.99 dBZ, we contribute to closing data gaps in the representation of clouds in observational data.

Design and rocket deployment of a trackable pseudo-Lagrangian drifter-based meteorological probe into the Lawrence/Linwood EF4 tornado and mesocyclone on 28 May 2019
Reed Timmer, Mark Simpson, Sean Schofer, and Curtis Brooks
Atmos. Meas. Tech., 17, 943–960, https://doi.org/10.5194/amt-17-943-2024, 2024
This work discusses a probe launched by a model rocket into an EF4 tornado and is the first time an airborne probe has directly sampled a tornado. The rocket deployed a parachuted probe recording wind speeds of 306 km h-1 in addition to temperature, humidity, and pressure deficit. Data from the probe were sent in real time to a receiver in an armored vehicle. Taking measurements directly from inside tornadoes provides new data about this violent phenomenon.

Working standard gas saving system for in-situ CO2 and CH4 measurements and calculation method for concentrations and their uncertainty
Motoki Sasakawa, Noritsugu Tsuda, Toshinobu Machida, Mikhail Arshinov, Denis Davydov, Aleksandr Fofonov, and Boris Belan
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2023-246,2024
Preprint under review for AMT (discussion: open, 0 comments)
To accurately monitor atmospheric greenhouse gases, stable measurements are needed. Environmental changes like atmospheric pressure can alter device output. We counteract this by measuring standard gases with known concentrations. However, these gases deplete quickly. To address this, we’ve developed a system using ambient air at the site, reducing standard gas consumption. This paper details the system and a method for calculating concentrations.

Long-term aerosol particle depolarization ratio measurements with HALO Photonics Doppler lidar
Viet Le, Hannah Lobo, Ewan J. O'Connor, and Ville Vakkari
Atmos. Meas. Tech., 17, 921–941, https://doi.org/10.5194/amt-17-921-2024, 2024
This study offers a long-term overview of aerosol particle depolarization ratio at the wavelength of 1565 nm obtained from vertical profiling measurements by Halo Doppler lidars during 4 years at four different locations across Finland. Our observations support the long-term usage of Halo Doppler lidar depolarization ratio such as the detection of aerosols that may pose a safety risk for aviation. Long-range Saharan dust transport and pollen transport are also showcased here.

Applicability of the inverse dispersion method to measure emissions from animal housings
Marcel Bühler, Christoph Häni, Albrecht Neftel, Patrice Bühler, Christof Ammann, and Thomas Kupper
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2023-258,2024
Preprint under review for AMT (discussion: open, 1 comment)
Methane was released from an artificial source inside a barn to test the applicability of the inverse dispersion method (IDM). Multiple open-path concentration devices and ultrasonic anemometers were used at the site. It is concluded that for the present study case, the effect of a building and a tree in the main wind axis led to a systematic underestimation of the IDM derived emission rate probably due to deviations of the wind field and turbulent dispersion from the ideal assumptions.

Role of time-averaging of eddy covariance fluxes on water use efficiency dynamics of Maize crop
Arun Rao Karimindla, Shweta Kumari, Saipriya SR, Syam Chintala, and BVN Phanindra Kambhammettu
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2023-253,2024
Preprint under review for AMT (discussion: open, 0 comments)
This study is aimed at investigating the role of the averaging period of Eddy Covariance (EC) fluxes on EBR and further propagation into WUE dynamics. Application was demonstrated on a Maize field considering EC flux data. We obtained that the time averages of EC fluxes that yield the most effective EBR are at 45 min and 60 min. The 30-min averaging period proves insufficient for capturing low-frequency fluxes. Time-averaging of EC fluxes needs to be performed based on crop growth stage.

Introducing the Video In Situ Snowfall Sensor (VISSS)
Maximilian Maahn, Dmitri Moisseev, Isabelle Steinke, Nina Maherndl, and Matthew D. Shupe
Atmos. Meas. Tech., 17, 899–919, https://doi.org/10.5194/amt-17-899-2024, 2024
The open-source Video In Situ Snowfall Sensor (VISSS) is a novel instrument for characterizing particle shape, size, and sedimentation velocity in snowfall. It combines a large observation volume with relatively high resolution and a design that limits wind perturbations. The open-source nature of the VISSS hardware and software invites the community to contribute to the development of the instrument, which has many potential applications in atmospheric science and beyond.

An intercomparison of EarthCARE cloud, aerosol, and precipitation retrieval products
Shannon L. Mason, Howard W. Barker, Jason N. S. Cole, Nicole Docter, David P. Donovan, Robin J. Hogan, Anja Hünerbein, Pavlos Kollias, Bernat Puigdomènech Treserras, Zhipeng Qu, Ulla Wandinger, and Gerd-Jan van Zadelhoff
Atmos. Meas. Tech., 17, 875–898, https://doi.org/10.5194/amt-17-875-2024, 2024
When the EarthCARE mission enters its operational phase, many retrieval data products will be available, which will overlap both in terms of the measurements they use and the geophysical quantities they report. In this pre-launch study, we use simulated EarthCARE scenes to compare the coverage and performance of many data products from the European Space Agency production model, with the intention of better understanding the relation between products and providing a compact guide to users.

Offshore methane detection and quantification from space using sun glint measurements with the GHGSat constellation
Jean-Philippe W. MacLean, Marianne Girard, Dylan Jervis, David Marshall, Jason McKeever, Antoine Ramier, Mathias Strupler, Ewan Tarrant, and David Young
Atmos. Meas. Tech., 17, 863–874, https://doi.org/10.5194/amt-17-863-2024, 2024
We demonstrate the capabilities of the GHGSat satellite constellation to detect and quantify offshore methane emissions using a sun glint observation mode. Using this technique, we observe offshore methane emissions from space ranging from 180 kg h−1 to 84 000 kg h−1. We further assess the instrument performance in offshore environments, both empirically and using analytical modelling, and find that the detection limit varies with latitude and season.

Quantifying H2S with a Picarro CRDS G2201-i and the effect of H2S on carbon isotopes
Jessica Salas-Navarro, John Stix, and J. Maarten de Moor
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2023-265,2024
Preprint under review for AMT (discussion: open, 1 comment)
We identified and quantified the effects of H2S on CO2 and CH4 concentrations and their respective isotopic compositions using a Picarro instrument model G2201-i. This interference was used to develop a new method to accurately quantify H2S concentrations with a G2201-i. Measuring CO2, CH4, and H2S concentrations in the gas phase within 20 minutes using a single instrument will significantly improve current analytical routines and has the potential to be a powerful tool for volcano monitoring.

Novel use of an adapted ultraviolet double monochromator for measurements of global and direct irradiance, ozone, and aerosol
Alexander Geddes, Ben Liley, Richard McKenzie, Michael Kotkamp, and Richard Querel
Atmos. Meas. Tech., 17, 827–838, https://doi.org/10.5194/amt-17-827-2024, 2024
In this paper we describe a unique spectrometer that has been developed and tested over 10 years at Lauder, New Zealand. The spectrometer in question, UV2, makes alternating measurements of global UV and direct sun UV irradiance. After an assessment of the instrument performance, we compare the ozone and aerosol optical depth derived from UV2 to other independent measurements, finding excellent agreement suggesting that UV2 could supersede these measurements, particularly for ozone.

Single-blind test of nine methane-sensing satellite systems from three continents
Evan D. Sherwin, Sahar H. El Abbadi, Philippine M. Burdeau, Zhan Zhang, Zhenlin Chen, Jeffrey S. Rutherford, Yuanlei Chen, and Adam R. Brandt
Atmos. Meas. Tech., 17, 765–782, https://doi.org/10.5194/amt-17-765-2024, 2024
Countries and companies increasingly rely on a growing fleet of satellites to find large emissions of climate-warming methane, particularly from oil and natural gas systems across the globe. We independently assessed the performance of nine such systems by releasing controlled, undisclosed amounts of methane as satellites passed overhead. The tested systems produced reliable detection and quantification results, including the smallest-ever emission detected from space in such a test.

Assessing atmospheric gravity wave spectra in the presence of observational gaps
Mohamed Mossad, Irina Strelnikova, Robin Wing, and Gerd Baumgarten
Atmos. Meas. Tech., 17, 783–799, https://doi.org/10.5194/amt-17-783-2024, 2024
This numerical study addresses observational gaps' impact on atmospheric gravity wave spectra. Three methods, fast Fourier transform (FFT), generalized Lomb–Scargle periodogram (GLS), and Haar structure function (HSF), were tested on synthetic data. HSF is best for spectra with negative slopes. GLS excels for flat and positive slopes and identifying dominant frequencies. Accurately estimating these aspects is crucial for understanding gravity wave dynamics and energy transfer in the atmosphere.

Identifying and correcting interferences to PTR-ToF-MS measurements of isoprene and other urban volatile organic compounds
Matthew M. Coggon, Chelsea E. Stockwell, Megan S. Claflin, Eva Y. Pfannerstill, Lu Xu, Jessica B. Gilman, Julia Marcantonio, Cong Cao, Kelvin Bates, Georgios I. Gkatzelis, Aaron Lamplugh, Erin F. Katz, Caleb Arata, Eric C. Apel, Rebecca S. Hornbrook, Felix Piel, Francesca Majluf, Donald R. Blake, Armin Wisthaler, Manjula Canagaratna, Brian M. Lerner, Allen H. Goldstein, John E. Mak, and Carsten Warneke
Atmos. Meas. Tech., 17, 801–825, https://doi.org/10.5194/amt-17-801-2024, 2024
Mass spectrometry is a tool commonly used to measure air pollutants. This study evaluates measurement artifacts produced in the proton-transfer-reaction mass spectrometer. We provide methods to correct these biases and better measure compounds that degrade air quality.

Wall loss of semi-volatile organic compounds in a Teflon bag chamber for the temperature range of 262–298 K: mechanistic insight on temperature dependence
Longkun He, Wenli Liu, Yatai Li, Jixuan Wang, Mikinori Kuwata, and Yingjun Liu
Atmos. Meas. Tech., 17, 755–764, https://doi.org/10.5194/amt-17-755-2024, 2024
We experimentally investigated vapor wall loss of n-alkanes in a Teflon chamber across a wide temperature range. Increased wall loss was observed at lower temperatures. Further analysis suggests that lower temperatures enhance partitioning of n-alkanes to the surface layer of a Teflon wall but slow their diffusion into the inner layer. The results are important for quantitative analysis of chamber experiments conducted at low temperatures, simulating wintertime or upper-tropospheric conditions.

The EarthCARE mission: science data processing chain overview
Michael Eisinger, Fabien Marnas, Kotska Wallace, Takuji Kubota, Nobuhiro Tomiyama, Yuichi Ohno, Toshiyuki Tanaka, Eichi Tomita, Tobias Wehr, and Dirk Bernaerts
Atmos. Meas. Tech., 17, 839–862, https://doi.org/10.5194/amt-17-839-2024, 2024
The Earth Cloud Aerosol and Radiation Explorer (EarthCARE) is an ESA–JAXA satellite mission to be launched in 2024. We presented an overview of the EarthCARE processors' development, with processors developed by teams in Europe, Japan, and Canada. EarthCARE will allow scientists to evaluate the representation of cloud, aerosol, precipitation, and radiative flux in weather forecast and climate models, with the objective to better understand cloud processes and improve weather and climate models.

Modular Multiplatform Compatible Air Measurement System (MoMuCAMS): a new modular platform for boundary layer aerosol and trace gas vertical measurements in extreme environments
Roman Pohorsky, Andrea Baccarini, Julie Tolu, Lenny H. E. Winkel, and Julia Schmale
Atmos. Meas. Tech., 17, 731–754, https://doi.org/10.5194/amt-17-731-2024, 2024
This manuscript presents a new tethered-balloon-based platform for in situ vertical measurements of aerosols and trace gases in the lower atmosphere of polar and alpine regions. The system can host various instrumental setups to target different research questions and features new instruments, in particular a miniaturized scanning electrical mobility spectrometer, deployed for the first time in a tethered balloon.