Atmos. Meas. techniques

Fast retrieval of XCO2 over east Asia based on Orbiting Carbon Observatory-2 (OCO-2) spectral measurements
Fengxin Xie, Tao Ren, Changying Zhao, Yuan Wen, Yilei Gu, Minqiang Zhou, Pucai Wang, Kei Shiomi, and Isamu Morino
Atmos. Meas. Tech., 17, 3949–3967, https://doi.org/10.5194/amt-17-3949-2024, 2024
This study demonstrates a new machine learning approach to efficiently and accurately estimate atmospheric carbon dioxide levels from satellite data. Rather than using traditional complex physics-based retrieval methods, neural network models are trained on simulated data to rapidly predict CO2 concentrations directly from satellite spectral measurements.

Transferability of machine-learning-based global calibration models for NO2 and NO low-cost sensors
Ayah Abu-Hani, Jia Chen, Vigneshkumar Balamurugan, Adrian Wenzel, and Alessandro Bigi
Atmos. Meas. Tech., 17, 3917–3931, https://doi.org/10.5194/amt-17-3917-2024, 2024
This study examined the transferability of machine learning calibration models among low-cost sensor units targeting NO2 and NO. The global models were evaluated under similar and different emission conditions. To counter cross-sensitivity, the study proposed integrating O3 measurements from nearby reference stations, in Switzerland. The models show substantial improvement when O3 measurements are incorporated, which is more pronounced when in regions with elevated O3 concentrations.

Sensitivity of thermodynamic profiles retrieved from ground-based microwave and infrared observations to additional input data from active remote sensing instruments and numerical weather prediction models
Laura Bianco, Bianca Adler, Ludovic Bariteau, Irina V. Djalalova, Timothy Myers, Sergio Pezoa, David D. Turner, and James M. Wilczak
Atmos. Meas. Tech., 17, 3933–3948, https://doi.org/10.5194/amt-17-3933-2024, 2024
The Tropospheric Remotely Observed Profiling via Optimal Estimation physical retrieval is used to retrieve temperature and humidity profiles from various combinations of passive and active remote sensing instruments, surface platforms, and numerical weather prediction models. The retrieved profiles are assessed against collocated radiosonde in non-cloudy conditions to assess the sensitivity of the retrievals to different input combinations. Case studies with cloudy conditions are also inspected.

A 2-year intercomparison of three methods for measuring black carbon concentration at a high-altitude research station in Europe
Sarah Tinorua, Cyrielle Denjean, Pierre Nabat, Véronique Pont, Mathilde Arnaud, Thierry Bourrianne, Maria Dias Alves, and Eric Gardrat
Atmos. Meas. Tech., 17, 3897–3915, https://doi.org/10.5194/amt-17-3897-2024, 2024
The three most widely used techniques for measuring black carbon (BC) have been deployed continuously for 2 years at a French high-altitude research station. Despite a similar temporal variation in the BC load, we found significant biases by up to a factor of 8 between the three instruments. This study raises questions about the relevance of using these instruments for specific background sites, as well as the processing of their data, which can vary according to the atmospheric conditions.

JAXA Level2 algorithms for EarthCARE mission from single to four sensors: new perspective of cloud, aerosol, radiation and dynamics
Hajime Okamoto, Kaori Sato, Tomoaki Nishizawa, Yoshitaka Jin, Takashi Nakajima, Minrui Wang, Masaki Satoh, Kentaroh Suzuki, Woosub Roh, Akira Yamauchi, Hiroaki Horie, Yuichi Ohno, Yuichiro Hagihara, Hiroshi Ishimoto, Rei Kudo, Takuji Kubota, and Toshiyuki Tanaka
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2024-101,2024
Preprint under review for AMT (discussion: open, 0 comments)
This article gives overviews of the JAXA L2 algorithms and products by Japanese science teams for EarthCARE. The algorithms provide corrected Doppler velocity, cloud particle shape and orientations, microphysics of clouds and aerosols, and radiative fluxes and heating rate. The retrievals by the algorithms are demonstrated and evaluated using NICAM/J-simulator outputs. The JAXA EarthCARE L2 products will bring new scientific knowledge about the clouds, aerosols, radiation and convections.

An easy-to-use water vapor sampling approach for stable isotope analysis using affordable membrane valve multi-foil bags
Adrian Dahlmann, John D. Marshall, David Dubbert, Mathias Hoffmann, and Maren Dubbert
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2024-43,2024
Preprint under review for AMT (discussion: open, 0 comments)
Water-stable isotopes are commonly used in hydrological and ecological research. Until now, measurements were obtained either destructive or directly in the field. Here, we present a novel, affordable, and easy-to-use approach to measure the stable isotope signatures of soil water. Our gas bag approach demonstrates a high accuracy and extends the usability by allowing water vapor samples to be collected and stored in the field without the need for an instrument or a permanent power supply.

Lidar–radar synergistic method to retrieve ice, supercooled water and mixed-phase cloud properties
Clémantyne Aubry, Julien Delanoë, Silke Groß, Florian Ewald, Frédéric Tridon, Olivier Jourdan, and Guillaume Mioche
Atmos. Meas. Tech., 17, 3863–3881, https://doi.org/10.5194/amt-17-3863-2024, 2024
Radar–lidar synergy is used to retrieve ice, supercooled water and mixed-phase cloud properties, making the most of the radar sensitivity to ice crystals and the lidar sensitivity to supercooled droplets. A first analysis of the output of the algorithm run on the satellite data is compared with in situ data during an airborne Arctic field campaign, giving a mean percent error of 49 % for liquid water content and 75 % for ice water content.

Simulations of the collection of mesospheric dust particles with a rocket instrument
Adrien Pineau, Henriette Trollvik, Herman Greaker, Sveinung Olsen, Yngve Eilertsen, and Ingrid Mann
Atmos. Meas. Tech., 17, 3843–3861, https://doi.org/10.5194/amt-17-3843-2024, 2024
The mesosphere, part of the upper atmosphere, contains small solid dust particles, mostly made up of material from interplanetary space. We are preparing an experiment to collect such particles during a rocket flight. A new instrument has been designed and numerical simulations have been performed to investigate the airflow nearby as well as its dust collection efficiency. The collected dust particles will be further analyzed in the laboratory in order to study their chemical composition.

A modular approach to volatile organic compound samplers for tethered balloon and drone platforms
Meghan Guagenti, Darielle Dexheimer, Alexandra Ulinksi, Paul Walter, James H. Flynn III, and Sascha Usenko
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2024-96,2024
Preprint under review for AMT (discussion: open, 0 comments)
A robust, automatic VOC collection system was developed for vertical volatile organic compounds (VOCs) sampling associated with the 2022 DOE ARM program-led TRACER in Houston, TX.  This modular sampler has been developed to measure vertical profiles of VOCs to improve near-surface characterization. This article helps fill the current lack of commercially available options for aerial VOC sampling and serves to support and encourage researchers to build and develop custom samplers. 

EMADDC: high quality, quickly available and high volume wind and temperature observations from aircraft using the Mode-S EHS infrastructure
Siebren de Haan, Paul de Jong, Michal Koutek, and Jan Sondij
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2024-110,2024
Preprint under review for AMT (discussion: open, 0 comments)
This manscript describes the operational method of extracting meteorological information from all airborne aircraft in the European airspace every 20 seconds to 1 minute. The methodology is described and the quality of the wind and temperature observations are evaluated against radiosonde observations.

Digitization and calibration of historical solar absorption infrared spectra from the Jungfraujoch site
Jamal Makkor, Mathias Palm, Matthias Buschmann, Emmanuel Mahieu, Martyn P. Chipperfield, and Justus Notholt
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2024-93,2024
Preprint under review for AMT (discussion: open, 0 comments)
During the years 1950 and 1951, Marcel Migeotte took regular solar measurements in form of paper rolls at the Jungfraujoch site. These historical spectra proved valuable for atmospheric research and needed to be saved for posterity. Therefore, a digitization method which used image processing techniques was developed to extract them from the historical paper rolls. This allowed them to be saved in a machine-readable format that is easily accessible to the scientific community.

Rapid quantitative analysis of SVOCs in indoor surface film using Direct Analysis in Real Time mass spectrometry: A case study on phthalates
Ying Zhou, Longkun He, Jiang Tan, Jiang Zhou, and Yingjun Liu
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2024-104,2024
Preprint under review for AMT (discussion: open, 0 comments)
This study presents a sensitive DART-MS/MS method for the fast and accurate quantification of SVOCs in organic films without the need for pre-treatment. This method developed herein offers substantially improved repeatability in the absence of internal standards. By utilizing MS/MS analysis, separation of isomeric components within films becomes possible. These developments increase the feasibility of the DART-MS approach for studying the dynamics of SVOCs in indoor surface film.

Scale separation for gravity wave analysis from 3D temperature observations in the mesosphere and lower thermosphere (MLT) region
Björn Linder, Peter Preusse, Qiuyu Chen, Ole Martin Christensen, Lukas Krasauskas, Linda Megner, Manfred Ern, and Jörg Gumbel
Atmos. Meas. Tech., 17, 3829–3841, https://doi.org/10.5194/amt-17-3829-2024, 2024
The Swedish research satellite MATS (Mesospheric Airglow/Aerosol Tomography and Spectroscopy) is designed to study atmospheric waves in the mesosphere and lower thermosphere. These waves perturb the temperature field, and thus, by observing three-dimensional temperature fluctuations, their properties can be quantified. This pre-study uses synthetic MATS data generated from a general circulation model to investigate how well wave properties can be retrieved.

Long-term evaluation of commercial air quality sensors: an overview from the QUANT (Quantification of Utility of Atmospheric Network Technologies) study
Sebastian Diez, Stuart Lacy, Hugh Coe, Josefina Urquiza, Max Priestman, Michael Flynn, Nicholas Marsden, Nicholas A. Martin, Stefan Gillott, Thomas Bannan, and Pete M. Edwards
Atmos. Meas. Tech., 17, 3809–3827, https://doi.org/10.5194/amt-17-3809-2024, 2024
In this paper we present an overview of the QUANT project, which to our knowledge is one of the largest evaluations of commercial sensors to date. The objective was to evaluate the performance of a range of commercial products and also to nourish the different applications in which these technologies can offer relevant information.

Evaluation of the hyperspectral radiometer (HSR1) at the Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) site
Kelly A. Balmes, Laura D. Riihimaki, John Wood, Connor Flynn, Adam Theisen, Michael Ritsche, Lynn Ma, Gary B. Hodges, and Christian Herrera
Atmos. Meas. Tech., 17, 3783–3807, https://doi.org/10.5194/amt-17-3783-2024, 2024
A new hyperspectral radiometer (HSR1) was deployed and evaluated in the central United States (northern Oklahoma). The HSR1 total spectral irradiance agreed well with nearby existing instruments, but the diffuse spectral irradiance was slightly smaller. The HSR1-retrieved aerosol optical depth (AOD) also agreed well with other retrieved AODs. The HSR1 performance is encouraging: new hyperspectral knowledge is possible that could inform atmospheric process understanding and weather forecasting.

Transport of the Hunga volcanic aerosols inferred from Himawari-8/9 limb measurements
Fred Prata
Atmos. Meas. Tech., 17, 3751–3764, https://doi.org/10.5194/amt-17-3751-2024, 2024
Geostationary satellite data have been used to measure the stratospheric aerosols from the explosive Hunga volcanic eruption by using the data in a novel way. The onboard imager views part of the Earth's limb and data from this region were analysed to generate vertical cross-sections of aerosols high in the atmosphere. The analyses show the hemispheric spread of the aerosols and their vertical structure in layers from 22–28 km in the stratosphere.

Innovative cloud quantification: deep learning classification and finite-sector clustering for ground-based all-sky imaging
Jingxuan Luo, Yubing Pan, Debin Su, Jinhua Zhong, Lingxiao Wu, Wei Zhao, Xiaoru Hu, Zhengchao Qi, Daren Lu, and Yinan Wang
Atmos. Meas. Tech., 17, 3765–3781, https://doi.org/10.5194/amt-17-3765-2024, 2024
Accurate cloud quantification is critical for climate research. We developed a novel computer vision framework using deep neural networks and clustering algorithms for cloud classification and segmentation from ground-based all-sky images. After a full year of observational training, our model achieves over 95 % accuracy on four cloud types. The framework enhances quantitative analysis to support climate research by providing reliable cloud data.

Revealing halos concealed by cirrus clouds
Yuji Ayatsuka
Atmos. Meas. Tech., 17, 3739–3750, https://doi.org/10.5194/amt-17-3739-2024, 2024
Many types of halos appear in the sky. Each type of halo reflects the state of the atmosphere; therefore observing them from the ground greatly helps in understanding the state of the atmosphere. However, halos are easily obscured by the contrast of the cloud itself, making it difficult to observe them. This study describes the construction of a sky-color model for halos and a new effective algorithm to reveal halos in images.

Algorithm to retrieve aerosol optical properties using lidar measurements on board the EarthCARE satellite
Tomoaki Nishizawa, Rei Kudo, Eiji Oikawa, Akiko Higurashi, Yoshitaka Jin, Nobuo Sugimoto, Kaori Sato, and Hajime Okamoto
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2024-100,2024
Preprint under review for AMT (discussion: open, 0 comments)
We developed algorithms to produce JAXA ATLID L2 aerosol products using ATLID L1 data. The algorithms estimate layer identifiers such as aerosol or cloud layers, (2) particle optical properties at 355 nm, (3) particle type identifiers, and (4) planetary boundary layer height. We demonstrated the algorithm performance using the simulated ATLID L1 data and found the algorithm’s capability to provide valuable insights into the global distribution of aerosols and clouds.

Enhanced Quantitative Precipitation Estimation (QPE) through the opportunistic use of Ku TV-sat links via a Dual-Channel Procedure
Louise Gelbart, Laurent Barthès, François Mercier-Tigrine, Aymeric Chazottes, and Cecile Mallet
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2024-88,2024
Preprint under review for AMT (discussion: open, 0 comments)
In this paper, we present and evaluate a new method for the quantitative estimation of precipitation from a low-cost sensor. Based on previous work measuring the attenuation of an electromagnetic signal from a broadcast television satellite, we make this approach more accurate so that to be easily deployed and used operationally in areas where rainfall measurements are critical for applications like flood monitoring. In this article, the method is validated in France and applied in Ivory Coast.