Atmos. Meas. techniques

Detection of small drizzle droplets in a large cloud chamber using ultrahigh-resolution radar
Zeen Zhu, Fan Yang, Pavlos Kollias, Raymond A. Shaw, Alex B. Kostinski, Steve Krueger, Katia Lamer, Nithin Allwayin, and Mariko Oue
Atmos. Meas. Tech., 17, 1133–1143, https://doi.org/10.5194/amt-17-1133-2024, 2024
In this article, we demonstrate the feasibility of applying advanced radar technology to detect liquid droplets generated in the cloud chamber. Specifically, we show that using radar with centimeter-scale resolution, single drizzle drops with a diameter larger than 40 µm can be detected. This study demonstrates the applicability of remote sensing instruments in laboratory experiments and suggests new applications of ultrahigh-resolution radar for atmospheric sensing.

The GeoCarb greenhouse gas retrieval algorithm: simulations and sensitivity to sources of uncertainty
Gregory R. McGarragh, Christopher W. O'Dell, Sean M. R. Crowell, Peter Somkuti, Eric B. Burgh, and Berrien Moore III
Atmos. Meas. Tech., 17, 1091–1121, https://doi.org/10.5194/amt-17-1091-2024, 2024
Carbon dioxide and methane are greenhouse gases that have been rapidly increasing due to human activity since the industrial revolution, leading to global warming and subsequently negative affects on the climate. It is important to measure the concentrations of these gases in order to make climate predictions that drive policy changes to mitigate climate change. GeoCarb aims to measure the concentrations of these gases from space over the Americas at unprecedented spatial and temporal scales.

Forward operator for polarimetric radio occultation measurements
Daisuke Hotta, Katrin Lonitz, and Sean Healy
Atmos. Meas. Tech., 17, 1075–1089, https://doi.org/10.5194/amt-17-1075-2024, 2024
Global Navigation Satellite System (GNSS) polarimetric radio occultation (PRO) is a new type of GNSS observations that can detect heavy precipitation along the ray path between the emitter and receiver satellites. As a first step towards using these observations in numerical weather prediction (NWP), we developed a computer code that simulates GNSS-PRO observations from forecast fields produced by an NWP model. The quality of the developed simulator is evaluated with a number of case studies.

Airborne lidar measurements of atmospheric CO2 column concentrations to cloud tops made during the 2017 ASCENDS/ABoVE campaign
Jianping Mao, James B. Abshire, S. Randy Kawa, Xiaoli Sun, and Haris Riris
Atmos. Meas. Tech., 17, 1061–1074, https://doi.org/10.5194/amt-17-1061-2024, 2024
NASA Goddard Space Flight Center has developed an integrated-path, differential absorption lidar approach to measure column-averaged atmospheric CO2 (XCO2). We demonstrated the lidar’s capability to measure XCO2 to cloud tops ,as well as to the ground, with the data from the summer 2017 airborne campaign in the US and Canada. This active remote sensing technique can provide all-sky data coverage and high-quality XCO2 measurements for future airborne science campaigns and space missions.

Ship-based lidar measurements for validating ASCAT-derived and ERA5 offshore wind profiles
Hugo Rubio, Daniel Hatfield, Charlotte Bay Hasager, Martin Kühn, and Julia Gottschall
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2024-11,2024
Preprint under review for AMT (discussion: open, 0 comments)
Unlocking offshore wind farms’ potential demands a precise understanding of available wind resources. Yet, limited in situ data in marine environments call for innovative solutions. This study delves into the world of satellite remote sensing and numerical models, exploring their capabilities and challenges in characterizing offshore wind dynamics. This investigation evaluates these tools against measurements from a floating ship-based lidar, collected through a novel campaign in the Baltic Sea.

Development and characterization of a high-performance single-particle aerosol mass spectrometer (HP-SPAMS)
Xubing Du, Qinhui Xie, Qing Huang, Xuan Li, Junlin Yang, Zhihui Hou, Jingjing Wang, Xue Li, Zhen Zhou, Zhengxu Huang, Wei Gao, and Lei Li
Atmos. Meas. Tech., 17, 1037–1050, https://doi.org/10.5194/amt-17-1037-2024, 2024
Currently, the limitations of single-particle mass spectrometry detection capabilities render it not yet well suited for analyzing complex aerosol components in low-concentration environments. In this study, a new high-performance single-particle aerosol mass spectrometer (HP-SPAMS) is developed to enhance instrument performance regarding the number of detected particles, transmission efficiency, resolution, and sensitivity, which will help in aerosol science.

Towards a hygroscopic growth calibration for low-cost PM2.5 sensors
Milan Y. Patel, Pietro F. Vannucci, Jinsol Kim, William M. Berelson, and Ronald C. Cohen
Atmos. Meas. Tech., 17, 1051–1060, https://doi.org/10.5194/amt-17-1051-2024, 2024
Low-cost particulate matter (PM) sensors are becoming increasingly common in community monitoring and atmospheric research, but these sensors require proper calibration to provide accurate reporting. Here, we propose a hygroscopic growth calibration scheme that evolves in time to account for seasonal changes in hygroscopic growth. In San Francisco and Los Angeles, CA, applying a seasonal hygroscopic growth calibration can account for sensor biases driven by the seasonal cycles in PM composition.

Determination of the vertical distribution of in-cloud particle shape using SLDR-mode 35 GHz scanning cloud radar
Audrey Teisseire, Patric Seifert, Alexander Myagkov, Johannes Bühl, and Martin Radenz
Atmos. Meas. Tech., 17, 999–1016, https://doi.org/10.5194/amt-17-999-2024, 2024
The vertical distribution of particle shape (VDPS) method, introduced in this study, aids in characterizing the density-weighted shape of cloud particles from scanning slanted linear depolarization ratio (SLDR)-mode cloud radar observations. The VDPS approach represents a new, versatile way to study microphysical processes by combining a spheroidal scattering model with real measurements of SLDR.

Ozone and aerosol optical depth retrievals using the ultraviolet multi-filter rotating shadow-band radiometer
Joseph Michalsky and Glen McConville
Atmos. Meas. Tech., 17, 1017–1022, https://doi.org/10.5194/amt-17-1017-2024, 2024
The ozone in the atmosphere is measured by looking at the sun and measuring how diminished the light in the ultraviolet is relative to how bright it is above the Earth's atmosphere. This typically uses spectral instruments that are either costly or no longer manufactured. This paper uses a relatively inexpensive interference filter instrument to perform the same task. Daily ozone measurements with the latter and this filter instrument are compared. Aerosols are calculated as a by-product.

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.