Atmos. Meas. techniques

Level0 to Level1B processor for MethaneAIR
Eamon K. Conway, Amir H. Souri, Joshua Benmergui, Kang Sun, Xiong Liu, Carly Staebell, Christopher Chan Miller, Jonathan Franklin, Jenna Samra, Jonas Wilzewski, Sebastien Roche, Bingkun Luo, Apisada Chulakadabba, Maryann Sargent, Jacob Hohl, Bruce Daube, Iouli Gordon, Kelly Chance, and Steven Wofsy
Atmos. Meas. Tech., 17, 1347–1362, https://doi.org/10.5194/amt-17-1347-2024, 2024
The work presented here describes the processes required to convert raw sensor data for the MethaneAIR instrument to geometrically calibrated data. Each algorithm is described in detail. MethaneAIR is the airborne simulator for MethaneSAT, a new satellite under development by MethaneSAT LLC, a subsidiary of the EDF. MethaneSAT's goals are to precisely map over 80 % of the production sources of methane emissions from oil and gas fields across the globe to a high degree of accuracy.

Quantifying the uncertainties in thermal-optical analysis of carbonaceous aircraft engine emissions: An interlaboratory study
Timothy Sipkens, Joel Corbin, Brett Smith, Stephanie Gagné, Prem Lobo, Benjamin Brem, Mark Johnson, and Gregory Smallwood
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2024-1,2024
Preprint under review for AMT (discussion: open, 0 comments)
Carbonaceous particles, such as soot, contribute to climate forcing, air pollution, and human health. Thermal-optical analysis is a calibration standard used to measure these particles, but significant differences have been observed in the measurements across identical instruments. We report on the reproducibility of these measurements for aircraft emissions, noting that interlaboratory differences increase uncertainties by a factor of 1.2 – 1.6 relative to the laboratory-reported uncertainties.

Exploiting the entire near-infrared spectral range to improve the detection of methane plumes with high-resolution imaging spectrometers
Javier Roger, Luis Guanter, Javier Gorroño, and Itziar Irakulis-Loitxate
Atmos. Meas. Tech., 17, 1333–1346, https://doi.org/10.5194/amt-17-1333-2024, 2024
Methane emissions can be identified using remote sensing, but surface-related structures disturb detection. In this work, a variation of the matched filter method that exploits a large fraction of the near-infrared range (1000–2500 nm) is applied. In comparison to the raw matched filter, it reduces background noise and strongly attenuates the surface-related artifacts, which leads to a greater detection capability. We propose this variation as a standard methodology for methane detection.

Consideration of the cloud motion for aircraft-based stereographically derived cloud geometry and cloud top heights
Lea Volkmer, Tobias Kölling, Tobias Zinner, and Bernhard Mayer
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2024-19,2024
Preprint under review for AMT (discussion: open, 0 comments)
The importance of the consideration of cloud motion for the stereographic determination of cloud top height from aircraft observations is demonstrated using measurements of the airborne spectrometer of the Munich Aerosol Cloud Scanner (specMACS). A method for the cloud motion correction using model winds from ECMWF is presented and validated using both, real measurements and realistic radiative transfer simulations.

The differences between remote sensing and in situ air pollutants measurements over the Canadian Oil Sands
Xiaoyi Zhao, Vitali Fioletov, Debora Griffin, Chris McLinden, Ralf Staebler, Cristian Mihele, Kevin Strawbridge, Jonathan Davies, Ihab Abboud, Sum Chi Lee, Alexander Cede, Martin Tiefengraber, and Robert Swap
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2024-27,2024
Preprint under review for AMT (discussion: open, 0 comments)
This study explores differences between remote sensing and in situ instruments in terms of their vertical, horizontal, and temporal sampling differences. Understanding and resolving these differences are critical for future analyses linking satellite, ground-based remote sensing, and in situ observations in air quality monitoring. It shows the meteorological conditions (wind directions, speed, and boundary layer conditions) will strongly affect the agreement between the two measurements.

Validation and field application of a low-cost device to measure CO2 and evapotranspiration (ET) fluxes
Reena Macagga, Michael Asante, Geoffroy Sossa, Danica Antonijević, Maren Dubbert, and Mathias Hoffmann
Atmos. Meas. Tech., 17, 1317–1332, https://doi.org/10.5194/amt-17-1317-2024, 2024
Using only low-cost microcontrollers and sensors, we constructed a measurement device to accurately and precisely obtain atmospheric carbon dioxide and water fluxes. The device was tested against known concentration increases and high-cost, commercial sensors during a laboratory and field experiment. We additionally tested the device over a longer period in a field study in Ghana during which the net ecosystem carbon balance and water use efficiency of maize cultivation were studied.

Ship- and aircraft-based XCH4 over oceans as a new tool for satellite validation
Astrid Müller, Hiroshi Tanimoto, Takafumi Sugita, Prabir K. Patra, Shin-ichiro Nakaoka, Toshinobu Machida, Isamu Morino, André Butz, and Kei Shiomi
Atmos. Meas. Tech., 17, 1297–1316, https://doi.org/10.5194/amt-17-1297-2024, 2024
Satellite CH4 observations with high accuracy are needed to understand changes in atmospheric CH4 concentrations. But over oceans, reference data are limited. We combine various ship and aircraft observations with the help of atmospheric chemistry models to derive observation-based column-averaged mixing ratios of CH4 (obs. XCH4). We discuss three different approaches and demonstrate the applicability of the new reference dataset for carbon cycle studies and satellite evaluation.

A novel probabilistic source apportionment approach: Bayesian auto-correlated matrix factorization
Anton Rusanen, Anton Björklund, Manousos I. Manousakas, Jianhui Jiang, Markku T. Kulmala, Kai Puolamäki, and Kaspar R. Daellenbach
Atmos. Meas. Tech., 17, 1251–1277, https://doi.org/10.5194/amt-17-1251-2024, 2024
We present a Bayesian non-negative matrix factorization model that performs better on our test datasets than currently widely used models. Its advantages are better use of time information and providing a direct error estimation. We believe this could lead to better estimates of emission sources from measurements.

Global evaluation of fast radiative transfer model coefficients for early meteorological satellite sensors
Bruna Barbosa Silveira, Emma Catherine Turner, and Jérôme Vidot
Atmos. Meas. Tech., 17, 1279–1296, https://doi.org/10.5194/amt-17-1279-2024, 2024
A fast radiative transfer model, used to speed up the full spectral simulation of meteorological satellite channels in weather forecast models, is tested using 25 000 modelled atmospheres. The differences between calculations from the fast and the high-resolution reference models are examined for nine historic weather satellite instruments. The study confirms that a reduced set of 83 atmospheric profiles is robust enough to estimate the scale of the differences obtained from the larger sample.

Detection and long-term quantification of methane emissions from an active landfill
Pramod Kumar, Christopher Caldow, Grégoire Broquet, Adil Shah, Olivier Laurent, Camille Yver-Kwok, Sebastien Ars, Sara Defratyka, Susan Warao Gichuki, Luc Lienhardt, Mathis Lozano, Jean-Daniel Paris, Felix Vogel, Caroline Bouchet, Elisa Allegrini, Robert Kelly, Catherine Juery, and Philippe Ciais
Atmos. Meas. Tech., 17, 1229–1250, https://doi.org/10.5194/amt-17-1229-2024, 2024
This study presents a series of mobile measurement campaigns to monitor the CH4 emissions from an active landfill. These measurements are processed using a Gaussian plume model and atmospheric inversion techniques to quantify the landfill CH4 emissions. The methane emission estimates range between ~0.4 and ~7 t CH4 per day, and their variations are analyzed. The robustness of the estimates is assessed depending on the distance of the measurements from the potential sources in the landfill.

A New Non-linearity Correction Method for Spectrum from GIIRS onboard Fengyun-4 Satellites and its Preliminary Assessments
Qiang Guo, Yuning Liu, Xin Wang, and Wen Hui
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2023-242,2024
Preprint under review for AMT (discussion: open, 3 comments)
Non-linearity (NL) correction is a critical procedure to guarantee the calibration accuracy of a spaceborne sensor to approach a good level. Different from the classical NL correction method, a new NL correction method for a spaceborne Fourier transform spectrometer is proposed. To overcome the inaccurate linear coefficient from two-point calibration influencing the NL correction, an iteration algorithm is established which is suitable for NL correction of both infrared and microwave sensors.

A traceable and continuous flow calibration method for gaseous elemental mercury at low ambient concentrations
Teodor D. Andron, Warren T. Corns, Igor Živković, Saeed Waqar Ali, Sreekanth Vijayakumaran Nair, and Milena Horvat
Atmos. Meas. Tech., 17, 1217–1228, https://doi.org/10.5194/amt-17-1217-2024, 2024
Atmospheric mercury monitoring is an important activity in order to model the global trajectory of this toxic element and to assess if certain areas are polluted or not in accordance to global guidelines. One of the analysers tested in this work is globally used in this regard due to its practicality compared with other devices. Because it is only calibrated by the manufacturer at very high concentrations, we wanted to see how it performs at ambient mercury concentrations.

A Nitrate Ion Chemical Ionization Atmospheric Pressure interface Time-of-Flight Mass Spectrometer (NO3− ToFCIMS): calibration and sensitivity study
Stéphanie Alage, Vincent Michoud, Sergio Harb, Bénédicte Picquet-Varrault, Manuela Cirtog, Avinash Kumar, Matti Rissanen, and Christopher Cantrell
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2024-20,2024
Preprint under review for AMT (discussion: open, 0 comments)
Calibration exercises are essential for determining the accuracy of instruments. We performed calibrations on a NO3¯ ToFCIMS instrument to determine its sensitivity and linearity for detecting various organic compounds. Our findings revealed significant variability, over several orders of magnitude, in the calibration factors obtained. The results suggest that relying on a single calibration factor from H2SO4 for the quantification of all compounds detected by this technique is not appropriate.

Geometrical and optical properties of cirrus clouds in Barcelona, Spain: analysis with the two-way transmittance method of 4 years of lidar measurements
Cristina Gil-Díaz, Michäel Sicard, Adolfo Comerón, Daniel Camilo Fortunato dos Santos Oliveira, Constantino Muñoz-Porcar, Alejandro Rodríguez-Gómez, Jasper R. Lewis, Ellsworth J. Welton, and Simone Lolli
Atmos. Meas. Tech., 17, 1197–1216, https://doi.org/10.5194/amt-17-1197-2024, 2024
In this paper, a statistical study of cirrus geometrical and optical properties based on 4 years of continuous ground-based lidar measurements with the Barcelona (Spain) Micro Pulse Lidar (MPL) is analysed. The cloud optical depth, effective column lidar ratio and linear cloud depolarisation ratio have been calculated by a new approach to the two-way transmittance method, which is valid for both ground-based and spaceborne lidar systems. Their associated errors are also provided.

High precision δ18O measurements of atmospheric dioxygen using optical-feedback cavity-enhanced absorption spectroscopy (OF-CEAS)
Clément Piel, Daniele Romanini, Morgane Farradèche, Justin Chaillot, Clémence Paul, Nicolas Bienville, Thomas Lauwers, Joana Sauze, Kévin Jaulin, Frédéric Prié, and Amaëlle Landais
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2024-14,2024
Preprint under review for AMT (discussion: open, 0 comments)
This paper introduces a new optical gas analyzer based on the Optical-Feedback Cavity-Enhanced Absorption Spectroscopy technique (OF-CEAS) enabling high temporal resolution and high precision measurement of δ18O and concentration of atmospheric O2. The results underscore the good agreement with dual inlet IRMS measurements and the ability of the instrument to monitor biological processes.

Profiling the molecular destruction rates of temperature and humidity as well as the turbulent kinetic energy dissipation in the convective boundary layer
Volker Wulfmeyer, Christoph Senff, Florian Späth, Andreas Behrendt, Diego Lange, Robert M. Banta, W. Alan Brewer, Andreas Wieser, and David D. Turner
Atmos. Meas. Tech., 17, 1175–1196, https://doi.org/10.5194/amt-17-1175-2024, 2024
A simultaneous deployment of Doppler, temperature, and water-vapor lidar systems is used to provide profiles of molecular destruction rates and turbulent kinetic energy (TKE) dissipation in the convective boundary layer (CBL). The results can be used for the parameterization of turbulent variables, TKE budget analyses, and the verification of weather forecast and climate models.

Improving the Gaussianity of Radar Reflectivity Departures between Observations and Simulations by Using the Symmetric Rain Rate
Yudong Gao, Lidou Huyan, Zheng Wu, and Bojun Liu
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2024-15,2024
Preprint under review for AMT (discussion: open, 0 comments)
This study uses the rain rate data to build the symmetric error model for radar reflectivity. The result shows the symmetric error model can improve the Gaussianity of radar reflectivity error, which is more consistent with most current data assimilation algorithms.

A high-accuracy dynamic dilution method for generating reference gas mixtures of carbonyl sulfide at sub-nanomole-per-mole levels for long-term atmospheric observation
Hideki Nara, Takuya Saito, Taku Umezawa, and Yasunori Tohjima
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2024-16,2024
Preprint under review for AMT (discussion: open, 1 comment)
We have developed a high-accuracy dynamic dilution system for generating reference gas mixtures containing carbonyl sulfide (COS). Although COS at ambient levels generally has poor storage stability, our approach involves dilution of a gas mixture containing micromole-per-mole levels of COS, the stability of which was validated for at least 10 years. Developed system has excellent dilution performance and will facilitate accurate instrumental calibration for atmospheric COS observation.

Impacts of anemometer changes, site relocations and processing methods on wind speed trends in China
Yi Liu, Lihong Zhou, Yingzuo Qin, Cesar Azorin-Molina, Cheng Shen, Rongrong Xu, and Zhenzhong Zeng
Atmos. Meas. Tech., 17, 1123–1131, https://doi.org/10.5194/amt-17-1123-2024, 2024
Our research analyzed China's wind speed data and addressed inconsistencies caused by factors like equipment changes and station relocations. After improving data quality, China's recent wind speed decrease reduced by 41 %, revealing an increasing trend. This emphasizes the importance of rigorous data processing for accurate trend assessments in various research fields.

A method for estimating localized CO2 emissions from co-located satellite XCO2 and NO2 images
Blanca Fuentes Andrade, Michael Buchwitz, Maximilian Reuter, Heinrich Bovensmann, Andreas Richter, Hartmut Boesch, and John P. Burrows
Atmos. Meas. Tech., 17, 1145–1173, https://doi.org/10.5194/amt-17-1145-2024, 2024
We developed a method to estimate CO2 emissions from localized sources, such as power plants, using satellite data and applied it to estimate CO2 emissions from the Bełchatów Power Station (Poland). As the detection of CO2 emission plumes from satellite data is difficult, we used observations of co-emitted NO2 to constrain the emission plume region. Our results agree with CO2 emission estimations based on the power-plant-generated power and emission factors.