Articles | Volume 18, issue 17
https://doi.org/10.5194/amt-18-4397-2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Special issue:
https://doi.org/10.5194/amt-18-4397-2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
10 Sep 2025
Research article |
| 10 Sep 2025
| 10 Sep 2025
Improving the accuracy in particle concentration measurements of a balloon-borne optical particle counter, UCASS
Institute for Physics of the Atmosphere, Johannes Gutenberg University, Mainz, Germany
Institute for Physics of the Atmosphere, Johannes Gutenberg University, Mainz, Germany
Konrad Kandler
Institute for Applied Geosciences, Technical University Darmstadt, Darmstadt, Germany
Luis Valero
Institute for Applied Geosciences, Technical University Darmstadt, Darmstadt, Germany
Jessica Girdwood
Particle Instruments & Diagnostics Research Group, University of Hertfordshire, Hatfield, Hertfordshire, AL10 9AB, United Kingdom
National Centre for Atmospheric Science, School of Earth, Atmospheric and Environmental Sciences, University of Manchester, Manchester, M13 9PL, United Kingdom
Chris Stopford
Particle Instruments & Diagnostics Research Group, University of Hertfordshire, Hatfield, Hertfordshire, AL10 9AB, United Kingdom
Warren Stanley
Particle Instruments & Diagnostics Research Group, University of Hertfordshire, Hatfield, Hertfordshire, AL10 9AB, United Kingdom
Luca K. Eichhorn
Institute for Physics of the Atmosphere, Johannes Gutenberg University, Mainz, Germany
Christian von Glahn
Institute for Physics of the Atmosphere, Johannes Gutenberg University, Mainz, Germany
Holger Tost
Institute for Physics of the Atmosphere, Johannes Gutenberg University, Mainz, Germany
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Ryan Vella, Sergey Gromov, Clara M. Nussbaumer, Laura Stecher, Matthias Kohl, Samuel Ruhl, Holger Tost, Jos Lelieveld, and Andrea Pozzer
Atmos. Chem. Phys., 25, 9885–9904, https://doi.org/10.5194/acp-25-9885-2025, https://doi.org/10.5194/acp-25-9885-2025, 2025
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This work examines the impact of replacing forests with farmland and grazing areas on atmospheric composition. Using a global climate–chemistry model, we found that deforestation reduces biogenic volatile organic compounds (BVOCs), increases farming emissions, and shifts ozone chemistry. These changes result in a slight cooling effect on the climate. Restoring natural vegetation could reverse some of these effects.
Claudia Di Biagio, Elisa Bru, Avila Orta, Servanne Chevaillier, Clarissa Baldo, Antonin Bergé, Mathieu Cazaunau, Sandra Lafon, Sophie Nowak, Edouard Pangui, Meinrat O. Andreae, Pavla Dagsson-Waldhauserova, Kebonyethata Dintwe, Konrad Kandler, James S. King, Amelie Chaput, Gregory S. Okin, Stuart Piketh, Thuraya Saeed, David Seibert, Zongbo Shi, Earle Williams, Pasquale Sellitto, and Paola Formenti
EGUsphere, https://doi.org/10.5194/egusphere-2025-3512, https://doi.org/10.5194/egusphere-2025-3512, 2025
This preprint is open for discussion and under review for Atmospheric Chemistry and Physics (ACP).
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Spectroscopy measurements show that the absorbance of dust in the far-infrared up to 25 μm is comparable in intensity to that in the mid-infrared (3–15μm) suggesting its relevance for dust direct radiative effect. Data evidence different absorption signatures for high and low/mid latitude dust, due to differences in mineralogical composition. These differences could be used to characterise the mineralogy and differentiate the origin of airborne dust based on infrared remote sensing observations.
Alkistis Papetta, Maria Kezoudi, Holger Baars, Athina Floutsi, Eleni Drakaki, Konrad Kandler, Elena Louca, Theodoros Christoudias, Eleni Marinou, Chris Stopford, Troy Thornberry, Vassilis Amiridis, Jean Sciare, and Franco Marenco
EGUsphere, https://doi.org/10.5194/egusphere-2025-3404, https://doi.org/10.5194/egusphere-2025-3404, 2025
This preprint is open for discussion and under review for Atmospheric Chemistry and Physics (ACP).
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Dust in the atmosphere affects air quality, weather, and climate, but measuring it is challenging. We used drones and ground-based instruments to study how dust particles interact with light and relate this to their mass. Current methods often underestimate large dust particles, leading to errors in dust quantity. Our results show that regional differences in dust must be considered to improve climate models and satellite observations.
Heiko Bozem, Philipp Joppe, Yun Li, Nicolas Emig, Armin Afchine, Anna Breuninger, Joachim Curtius, Stefan Hofmann, Sadath Ismayil, Konrad Kandler, Daniel Kunkel, Arthur Kutschka, Hans-Christoph Lachnitt, Andreas Petzold, Sarah Richter, Timo Röschenthaler, Christian Rolf, Lisa Schneider, Johannes Schneider, Alexander Vogel, and Peter Hoor
EGUsphere, https://doi.org/10.5194/egusphere-2025-3175, https://doi.org/10.5194/egusphere-2025-3175, 2025
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Deployed on a Learjet as a tandem measurement platform during TPEx I (TropoPause composition gradients and mixing Experiment) campaign in June 2024, the new TPC-TOSS (TropoPause Composition Towed Sensor Shuttle) system delivers high-resolution in situ data on ozone, aerosol, clouds, and key weather parameters. Laboratory and in-flight tests confirmed its precision and stability. Observed gradients near the tropopause reveal active mixing and transport processes in the tropopause region.
Jesús Yus-Díez, Jeronimo Escribano, Marco Pandolfi, Andres Alastuey, Cristina González-Flórez, Adolfo Gonzalez-Romero, Maria Gonçalves Ageitos, Matic Ivančič, Martina Klose, Konrad Kandler, Vicenzo Obiso, Agnesh Panta, Cristina Reche, Martin Rigler, Xavier Querol, and Carlos Perez Garćia-Pando
EGUsphere, https://doi.org/10.5194/egusphere-2025-2571, https://doi.org/10.5194/egusphere-2025-2571, 2025
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Here we present measurements of dust optical properties during active emissions at a source region in the Moroccan Sahara. We present results on its single scattering albedo, absorption and scattering wavelength dependence and mass efficiency. Furthermore, we have performed imaginary refractive index (k) retrieval under varying assumptions of the refractive index real part, and particle sphericity. We also provide a comparison between the k retrievals and estimations on dust k from AERONET.
Marilena Teri, Josef Gasteiger, Katharina Heimerl, Maximilian Dollner, Manuel Schöberl, Petra Seibert, Anne Tipka, Thomas Müller, Sudharaj Aryasree, Konrad Kandler, and Bernadett Weinzierl
Atmos. Chem. Phys., 25, 6633–6662, https://doi.org/10.5194/acp-25-6633-2025, https://doi.org/10.5194/acp-25-6633-2025, 2025
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The A-LIFE aircraft field experiment was carried out in the eastern Mediterranean in 2017. Using A-LIFE data, we studied the change in mineral dust optical properties due to mixing with anthropogenic aerosols. We found that increasing pollution affects dust optical properties, which has implications for identifying dust events and understanding their climate effects. We also show that optical properties of Saharan and Arabian dust are similar when comparing cases with equal pollution content.
Matthias Kohl, Christoph Brühl, Jennifer Schallock, Holger Tost, Patrick Jöckel, Adrian Jost, Steffen Beirle, Michael Höpfner, and Andrea Pozzer
Geosci. Model Dev., 18, 3985–4007, https://doi.org/10.5194/gmd-18-3985-2025, https://doi.org/10.5194/gmd-18-3985-2025, 2025
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SO2 from explosive volcanic eruptions reaching the stratosphere can oxidize and form sulfur aerosols, potentially persisting for several years. We developed a new submodel, Explosive Volcanic ERuptions (EVER), that seamlessly includes stratospheric volcanic SO2 emissions in global numerical simulations based on a novel standard historical model setup, successfully evaluated with satellite observations. Sensitivity studies on the Nabro eruption in 2011 evaluate different emission methods.
Sylvain Dupont, Eric Lamaud, Mark R. Irvine, Jean-Marc Bonnefond, Adolfo González-Romero, Andrés Alastuey, Cristina González-Flórez, Xavier Querol, Konrad Kandler, Martina Klose, and Carlos Pérez García-Pando
Atmos. Meas. Tech., 18, 2183–2200, https://doi.org/10.5194/amt-18-2183-2025, https://doi.org/10.5194/amt-18-2183-2025, 2025
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Low-cost optical particle counters (OPCs) offer new opportunities to monitor dust particles from wind soil erosion. Their price, size, and power consumption are lower than those of traditional OPCs. We tested the ability of the low-cost OPC-N3 from Alphasense to estimate dust emission flux during erosion events in Jordan. N3 estimated the dust flux well, with differences of less than 30 % compared to a traditional OPC. Our results confirm the potential of low-cost OPCs for dust erosion research.
Hannah Meyer, Konrad Kandler, Sylvain Dupont, Jerónimo Escribano, Jessica Girdwood, George Nikolich, Andrés Alastuey, Vicken Etyemezian, Cristina González Flórez, Adolfo González-Romero, Tareq Hussein, Mark Irvine, Peter Knippertz, Ottmar Möhler, Xavier Querol, Chris Stopford, Franziska Vogel, Frederik Weis, Andreas Wieser, Carlos Pérez García-Pando, and Martina Klose
EGUsphere, https://doi.org/10.5194/egusphere-2025-1531, https://doi.org/10.5194/egusphere-2025-1531, 2025
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Mineral dust particles emitted from dry soils are of various sizes, yet the abundance of very large particles is not well understood. Here we measured the dust size distribution from fine to giant particles at an emission source during a field campaign in Jordan (J-WADI) using multiple instruments. Our findings show that large particles make up a significant part of the total dust mass. This knowledge is essential to improve climate models and to predict dust impacts on climate and environment.
Philipp Joppe, Johannes Schneider, Jonas Wilsch, Heiko Bozem, Anna Breuninger, Joachim Curtius, Martin Ebert, Nicolas Emig, Peter Hoor, Sadath Ismayil, Konrad Kandler, Daniel Kunkel, Isabel Kurth, Hans-Christoph Lachnitt, Yun Li, Annette Miltenberger, Sarah Richter, Christian Rolf, Lisa Schneider, Cornelis Schwenk, Nicole Spelten, Alexander L. Vogel, Yafang Cheng, and Stephan Borrmann
EGUsphere, https://doi.org/10.5194/egusphere-2025-1346, https://doi.org/10.5194/egusphere-2025-1346, 2025
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We show measurements of a filament with biomass burning influence transported by a warm conveyor belt (WCB) into the tropopause region over Europe. The pollution originates from Canadian forest fires and is transported in the lower troposphere towards Europe. The WCB transport is followed by mixing with air masses of stratospheric chemical signatures. We hypothesize that this mixing leads to a change in the vertical gradient of the potential temperature.
Lasse Moormann, Thomas Böttger, Philipp Schuhmann, Luis Valero, Friederike Fachinger, and Frank Drewnick
Atmos. Meas. Tech., 18, 1441–1459, https://doi.org/10.5194/amt-18-1441-2025, https://doi.org/10.5194/amt-18-1441-2025, 2025
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The drone-based Flying Laboratory FLab was developed to simultaneously measure aerosol (number concentration, size distribution, and black carbon), trace gas (O3, CO2), and meteorological variables. FLab was characterized in the field regarding limitations and biases due to different flight maneuvers. Two application cases are presented: analysis of the development of the lowermost troposphere (up to 300 m) and successfully bridging ground-based and aircraft- and radiosonde-based measurements.
Agnesh Panta, Konrad Kandler, Kerstin Schepanski, Andres Alastuey, Pavla Dagsson Waldhauserova, Sylvain Dupont, Melanie Eknayan, Cristina González-Flórez, Adolfo González-Romero, Martina Klose, Mara Montag, Xavier Querol, Jesús Yus-Díez, and Carlos Pérez García-Pando
EGUsphere, https://doi.org/10.5194/egusphere-2025-494, https://doi.org/10.5194/egusphere-2025-494, 2025
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Iceland is among the most active dust source areas in the world. Dust properties are influenced by particle size, mineralogy, shape, and mixing state. This work characterizes freshly emitted individual aerosol particles of Icelandic dust using electron microscopy. Our study provides insights into critical particle-specific information will contribute to better constraining climate models that consider mineralogical variations in their representation of the dust cycle.
Birte Klug, Ralf Weigel, Konrad Kandler, Markus Rapp, Manuel Baumgartner, Thomas Böttger, Klaus Dieter Wilhelm, Harald Rott, Thomas Kenntner, Oliver Drescher, and Anna Hundertmark
EGUsphere, https://doi.org/10.5194/egusphere-2025-510, https://doi.org/10.5194/egusphere-2025-510, 2025
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The nuclei onto which noctilucent clouds (NLC) form are largely unknown. We investigated the development of an inertia-based particle collector allowing for sampling NLC particles during a sounding rocket flight for off-line single particle physico-chemical analyzes. Computational fluid dynamics simulations (for Mach numbers 1.31 and 1.75) support the design and development process in reference to a basic mechanical concept of particle sampling and sample storage, which is also presented here.
Adrienne Jeske and Holger Tost
EGUsphere, https://doi.org/10.5194/egusphere-2025-293, https://doi.org/10.5194/egusphere-2025-293, 2025
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Thunderstorms lead to a vertical redistribution of tracers throughout the troposphere. We applied a new tool, the convective exchange matrix, in historical simulations with a chemistry-climate model to investigate the trends in convective transport. This reveals that convection reaches higher but deep convection occurs less often in the time period from 2011 to 2020 than in the 1980ies. Thus, convective transport towards the upper troposphere has declined as an adaptation to climate change.
Sarah Brüning and Holger Tost
EGUsphere, https://doi.org/10.5194/egusphere-2025-374, https://doi.org/10.5194/egusphere-2025-374, 2025
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This study analyses the temporal variability and life-cycle of spatially organised convective clouds, frequently associated with severe weather. We derive the data from a machine learning-based 3D extrapolation of 2D satellite data. The results highlight the impact of convective organisation on horizontal and vertical cloud properties and a prolonged cloud life-cycle. Overall, our findings emphasise a more intense activity over land but enhanced seasonal changes over the ocean.
Sarah Brüning and Holger Tost
EGUsphere, https://doi.org/10.5194/egusphere-2025-376, https://doi.org/10.5194/egusphere-2025-376, 2025
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The connection between convective cloud organisation and severe weather demands a robust characterisation of hazardous clouds. This study sets on to investigate spatio-temporal patterns and regional hotspots of convective organisation using machine learning-based 3D data and combining different organisation indices. While limitations arise due to overlapping effects of isolated and clustered convection, we emphasise the impact of a surface-specific seasonality that depends on the hemisphere.
Jessica Girdwood, Harry Ballington, Chris Stopford, Rob Lewis, and Evelyn Hesse
Atmos. Meas. Tech., 18, 305–317, https://doi.org/10.5194/amt-18-305-2025, https://doi.org/10.5194/amt-18-305-2025, 2025
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Optical particle spectrometers (OPSs) are a class of instruments (commonly used for measurement of particle size distributions) that require calibration. Conventionally, this is performed using a known aerosol source, which has reliability issues. In this paper, we present a technique for OPS calibration which involves placing objects in the instrument that generate a known response. This fibre calibration method was more reliable than a conventional calibration.
Ryan Vella, Matthew Forrest, Andrea Pozzer, Alexandra P. Tsimpidi, Thomas Hickler, Jos Lelieveld, and Holger Tost
Atmos. Chem. Phys., 25, 243–262, https://doi.org/10.5194/acp-25-243-2025, https://doi.org/10.5194/acp-25-243-2025, 2025
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This study examines how land cover changes influence biogenic volatile organic compound (BVOC) emissions and atmospheric states. Using a coupled chemistry–climate–vegetation model, we compare present-day land cover (deforested for crops and grazing) with natural vegetation and an extreme reforestation scenario. We find that vegetation changes significantly impact global BVOC emissions and organic aerosols but have a relatively small effect on total aerosols, clouds, and radiative effects.
Chun Hang Chau, Peter Hoor, and Holger Tost
EGUsphere, https://doi.org/10.5194/egusphere-2024-3805, https://doi.org/10.5194/egusphere-2024-3805, 2024
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This study examines how the turbulence in the upper troposphere/lower stratosphere could modify the tracer distribution under different situations. Using a multi-scale chemistry model, we find that both the pre-existing tracer gradient and the dynamical and thermodynamically forcing play a role in modifying the tracer distribution. These results allow further research on the UTLS turbulent mixing and its implications for the climate system.
Lisa Schneider, Jann Schrod, Daniel Weber, Heinz Bingemer, Konrad Kandler, Joachim Curtius, and Martin Ebert
EGUsphere, https://doi.org/10.5194/egusphere-2024-2797, https://doi.org/10.5194/egusphere-2024-2797, 2024
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Ice nucleating particles (INP) are important for cloud formation and properties influencing weather and climate. This article presents a method coupling an offline ice nucleus counter to an electron microscope to gain information not only about INP number concentrations but also on important features (size, shape and chemical composition) relevant to ice nucleation on single particles. The method was evaluated on the basis of a case study at the high-altitude research station Jungfraujoch.
Adolfo González-Romero, Cristina González-Flórez, Agnesh Panta, Jesús Yus-Díez, Patricia Córdoba, Andres Alastuey, Natalia Moreno, Melani Hernández-Chiriboga, Konrad Kandler, Martina Klose, Roger N. Clark, Bethany L. Ehlmann, Rebecca N. Greenberger, Abigail M. Keebler, Phil Brodrick, Robert Green, Paul Ginoux, Xavier Querol, and Carlos Pérez García-Pando
Atmos. Chem. Phys., 24, 9155–9176, https://doi.org/10.5194/acp-24-9155-2024, https://doi.org/10.5194/acp-24-9155-2024, 2024
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In this research, we studied the dust-emitting properties of crusts and aeolian ripples from the Mojave Desert. These properties are key to understanding the effect of dust upon climate. We found two different playa lakes according to the groundwater regime, which implies differences in crusts' cohesion state and mineralogy, which can affect the dust emission potential and properties. We also compare them with Moroccan Sahara crusts and Icelandic top sediments.
Anna Martin, Veronika Gayler, Benedikt Steil, Klaus Klingmüller, Patrick Jöckel, Holger Tost, Jos Lelieveld, and Andrea Pozzer
Geosci. Model Dev., 17, 5705–5732, https://doi.org/10.5194/gmd-17-5705-2024, https://doi.org/10.5194/gmd-17-5705-2024, 2024
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The study evaluates the land surface and vegetation model JSBACHv4 as a replacement for the simplified submodel SURFACE in EMAC. JSBACH mitigates earlier problems of soil dryness, which are critical for vegetation modelling. When analysed using different datasets, the coupled model shows strong correlations of key variables, such as land surface temperature, surface albedo and radiation flux. The versatility of the model increases significantly, while the overall performance does not degrade.
Adolfo González-Romero, Cristina González-Flórez, Agnesh Panta, Jesús Yus-Díez, Patricia Córdoba, Andres Alastuey, Natalia Moreno, Konrad Kandler, Martina Klose, Roger N. Clark, Bethany L. Ehlmann, Rebecca N. Greenberger, Abigail M. Keebler, Phil Brodrick, Robert O. Green, Xavier Querol, and Carlos Pérez García-Pando
Atmos. Chem. Phys., 24, 6883–6910, https://doi.org/10.5194/acp-24-6883-2024, https://doi.org/10.5194/acp-24-6883-2024, 2024
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The knowledge of properties from dust emitted in high latitudes such as in Iceland is scarce. This study focuses on the particle size, mineralogy, cohesion, and iron mode of occurrence and reflectance spectra of dust-emitting sediments. Icelandic top sediments have lower cohesion state, coarser particle size, distinctive mineralogy, and 3-fold bulk Fe content, with a large presence of magnetite compared to Saharan crusts.
Edward Groot, Patrick Kuntze, Annette Miltenberger, and Holger Tost
Weather Clim. Dynam., 5, 779–803, https://doi.org/10.5194/wcd-5-779-2024, https://doi.org/10.5194/wcd-5-779-2024, 2024
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Deep convective clouds (thunderstorms), which may cause severe weather, tend to coherently organise into structured cloud systems. Accurate representation of these systems in models is difficult due to their complex dynamics and, in numerical simulations, the dependence of their dynamics on resolution. Here, the effect of convective organisation and geometry on their outflow winds (altitudes of 7–14 km) is investigated. Representation of their dynamics and outflows improves at higher resolution.
Martin Ebert, Ralf Weigel, Stephan Weinbruch, Lisa Schneider, Konrad Kandler, Stefan Lauterbach, Franziska Köllner, Felix Plöger, Gebhard Günther, Bärbel Vogel, and Stephan Borrmann
Atmos. Chem. Phys., 24, 4771–4788, https://doi.org/10.5194/acp-24-4771-2024, https://doi.org/10.5194/acp-24-4771-2024, 2024
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Particles were collected during the flight campaign StratoClim 2017 within the Asian tropopause aerosol layer (ATAL). Refractory particles from seven different flights were characterized by scanning and transmission electron microscopy (SEM, TEM). The most abundant refractory particles are silicates and non-volatile organics. The most important sources are combustion processes at the ground and the agitation of soil material. During one flight, small cinnabar particles (HgS) were also detected.
Simon Rosanka, Holger Tost, Rolf Sander, Patrick Jöckel, Astrid Kerkweg, and Domenico Taraborrelli
Geosci. Model Dev., 17, 2597–2615, https://doi.org/10.5194/gmd-17-2597-2024, https://doi.org/10.5194/gmd-17-2597-2024, 2024
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The capabilities of the Modular Earth Submodel System (MESSy) are extended to account for non-equilibrium aqueous-phase chemistry in the representation of deliquescent aerosols. When applying the new development in a global simulation, we find that MESSy's bias in modelling routinely observed reduced inorganic aerosol mass concentrations, especially in the United States. Furthermore, the representation of fine-aerosol pH is particularly improved in the marine boundary layer.
Sarah Brüning, Stefan Niebler, and Holger Tost
Atmos. Meas. Tech., 17, 961–978, https://doi.org/10.5194/amt-17-961-2024, https://doi.org/10.5194/amt-17-961-2024, 2024
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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.
Adolfo González-Romero, Cristina González-Flórez, Agnesh Panta, Jesús Yus-Díez, Cristina Reche, Patricia Córdoba, Natalia Moreno, Andres Alastuey, Konrad Kandler, Martina Klose, Clarissa Baldo, Roger N. Clark, Zongbo Shi, Xavier Querol, and Carlos Pérez García-Pando
Atmos. Chem. Phys., 23, 15815–15834, https://doi.org/10.5194/acp-23-15815-2023, https://doi.org/10.5194/acp-23-15815-2023, 2023
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The effect of dust emitted from desertic surfaces upon climate and ecosystems depends on size and mineralogy, but data from soil mineral atlases of desert soils are scarce. We performed particle-size distribution, mineralogy, and Fe speciation in southern Morocco. Results show coarser particles with high quartz proportion are near the elevated areas, while in depressed areas, sizes are finer, and proportions of clays and nano-Fe oxides are higher. This difference is important for dust modelling.
Francesco Cairo, Martina Krämer, Armin Afchine, Guido Di Donfrancesco, Luca Di Liberto, Sergey Khaykin, Lorenza Lucaferri, Valentin Mitev, Max Port, Christian Rolf, Marcel Snels, Nicole Spelten, Ralf Weigel, and Stephan Borrmann
Atmos. Meas. Tech., 16, 4899–4925, https://doi.org/10.5194/amt-16-4899-2023, https://doi.org/10.5194/amt-16-4899-2023, 2023
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Cirrus clouds have been observed over the Himalayan region between 10 km and the tropopause at 17–18 km. Data from backscattersonde, hygrometers, and particle cloud spectrometers have been compared to assess their consistency. Empirical relationships between optical parameters accessible with remote sensing lidars and cloud microphysical parameters (such as ice water content, particle number and surface area density, and particle aspherical fraction) have been established.
Ryan Vella, Andrea Pozzer, Matthew Forrest, Jos Lelieveld, Thomas Hickler, and Holger Tost
Biogeosciences, 20, 4391–4412, https://doi.org/10.5194/bg-20-4391-2023, https://doi.org/10.5194/bg-20-4391-2023, 2023
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We investigated the effect of the El Niño–Southern Oscillation (ENSO) on biogenic volatile organic compound (BVOC) emissions from plants. ENSO events can cause a significant increase in these emissions, which have a long-term impact on the Earth's atmosphere. Persistent ENSO conditions can cause long-term changes in vegetation, resulting in even higher BVOC emissions. We link ENSO-induced emission anomalies with driving atmospheric and vegetational variables.
Silke Groß, Tina Jurkat-Witschas, Qiang Li, Martin Wirth, Benedikt Urbanek, Martina Krämer, Ralf Weigel, and Christiane Voigt
Atmos. Chem. Phys., 23, 8369–8381, https://doi.org/10.5194/acp-23-8369-2023, https://doi.org/10.5194/acp-23-8369-2023, 2023
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Aviation-emitted aerosol can have an impact on cirrus clouds. We present optical and microphysical properties of mid-latitude cirrus clouds which were formed under the influence of aviation-emitted aerosol or which were formed under rather pristine conditions. We find that cirrus clouds affected by aviation-emitted aerosol show larger values of the particle linear depolarization ratio, larger mean effective ice particle diameters and decreased ice particle number concentrations.
Cristina González-Flórez, Martina Klose, Andrés Alastuey, Sylvain Dupont, Jerónimo Escribano, Vicken Etyemezian, Adolfo Gonzalez-Romero, Yue Huang, Konrad Kandler, George Nikolich, Agnesh Panta, Xavier Querol, Cristina Reche, Jesús Yus-Díez, and Carlos Pérez García-Pando
Atmos. Chem. Phys., 23, 7177–7212, https://doi.org/10.5194/acp-23-7177-2023, https://doi.org/10.5194/acp-23-7177-2023, 2023
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Atmospheric mineral dust consists of tiny mineral particles that are emitted by wind erosion from arid regions. Its particle size distribution (PSD) affects its impact on the Earth's system. Nowadays, there is an incomplete understanding of the emitted dust PSD and a lot of debate about its variability. Here, we try to address these issues based on the measurements performed during a wind erosion and dust emission field campaign in the Moroccan Sahara within the framework of FRAGMENT project.
Robert Wagner, Alexander D. James, Victoria L. Frankland, Ottmar Möhler, Benjamin J. Murray, John M. C. Plane, Harald Saathoff, Ralf Weigel, and Martin Schnaiter
Atmos. Chem. Phys., 23, 6789–6811, https://doi.org/10.5194/acp-23-6789-2023, https://doi.org/10.5194/acp-23-6789-2023, 2023
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Polar stratospheric clouds (PSCs) play an important role in the depletion of stratospheric ozone. They can consist of different chemical species, including crystalline nitric acid hydrates. We found that mineral dust or meteoric ablation material can efficiently catalyse the formation of a specific phase of nitric acid dihydrate crystals. We determined predominant particle shapes and infrared optical properties of these crystals, which are important inputs for remote sensing detection of PSCs.
Edward Groot and Holger Tost
Atmos. Chem. Phys., 23, 6065–6081, https://doi.org/10.5194/acp-23-6065-2023, https://doi.org/10.5194/acp-23-6065-2023, 2023
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It is shown that the outflow from cumulonimbus clouds or thunderstorms in the upper troposphere and lower stratosphere in idealized high-resolution simulations (LESs) depends linearly on the net amount of latent heat released by the cloud for fixed geometry of the clouds. However, it is shown that, in more realistic situations, convective organization and aggregation (collecting mechanisms of cumulonimbus clouds) affect the amount of outflow non-linearly through non-idealized geometry.
Agnesh Panta, Konrad Kandler, Andres Alastuey, Cristina González-Flórez, Adolfo González-Romero, Martina Klose, Xavier Querol, Cristina Reche, Jesús Yus-Díez, and Carlos Pérez García-Pando
Atmos. Chem. Phys., 23, 3861–3885, https://doi.org/10.5194/acp-23-3861-2023, https://doi.org/10.5194/acp-23-3861-2023, 2023
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Desert dust is a major aerosol component of the Earth system and affects the climate. Dust properties are influenced by particle size, mineralogy, shape, and mixing state. This work characterizes freshly emitted individual mineral dust particles from a major source region using electron microscopy. Our new insights into critical particle-specific information will contribute to better constraining climate models that consider mineralogical variations in their representation of the dust cycle.
Ryan Vella, Matthew Forrest, Jos Lelieveld, and Holger Tost
Geosci. Model Dev., 16, 885–906, https://doi.org/10.5194/gmd-16-885-2023, https://doi.org/10.5194/gmd-16-885-2023, 2023
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Biogenic volatile organic compounds (BVOCs) are released by vegetation and have a major impact on atmospheric chemistry and aerosol formation. Non-interacting vegetation constrains the majority of numerical models used to estimate global BVOC emissions, and thus, the effects of changing vegetation on emissions are not addressed. In this work, we replace the offline vegetation with dynamic vegetation states by linking a chemistry–climate model with a global dynamic vegetation model.
Edward Groot and Holger Tost
Atmos. Chem. Phys., 23, 565–585, https://doi.org/10.5194/acp-23-565-2023, https://doi.org/10.5194/acp-23-565-2023, 2023
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Thunderstorm systems play an important role in the dynamics of the Earth’s atmosphere, and some of them form a well-organised line: squall lines. Simulations of such squall lines with very small initial perturbations are compared to a reference simulation. The evolution of perturbations and processes amplifying them are analysed. It is shown that the formation of new secondary thunderstorm cells (after the initial primary cells) directly ahead of the line affects the spread strongly.
Mohamed Abdelkader, Georgiy Stenchikov, Andrea Pozzer, Holger Tost, and Jos Lelieveld
Atmos. Chem. Phys., 23, 471–500, https://doi.org/10.5194/acp-23-471-2023, https://doi.org/10.5194/acp-23-471-2023, 2023
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We study the effect of injected volcanic ash, water vapor, and SO2 on the development of the volcanic cloud and the stratospheric aerosol optical depth (AOD). Both are sensitive to the initial injection height and to the aging of the volcanic ash shaped by heterogeneous chemistry coupled with the ozone cycle. The paper explains the large differences in AOD for different injection scenarios, which could improve the estimate of the radiative forcing of volcanic eruptions.
Oliver Appel, Franziska Köllner, Antonis Dragoneas, Andreas Hünig, Sergej Molleker, Hans Schlager, Christoph Mahnke, Ralf Weigel, Max Port, Christiane Schulz, Frank Drewnick, Bärbel Vogel, Fred Stroh, and Stephan Borrmann
Atmos. Chem. Phys., 22, 13607–13630, https://doi.org/10.5194/acp-22-13607-2022, https://doi.org/10.5194/acp-22-13607-2022, 2022
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This paper clarifies the chemical composition of the Asian tropopause aerosol layer (ATAL) by means of airborne in situ aerosol mass spectrometry (AMS). Ammonium nitrate and organics are found to significantly contribute to the particle layer, while sulfate does not show a layered structure. An analysis of the single-particle mass spectra suggests that secondary particle formation and subsequent growth dominate the particle composition, rather than condensation on pre-existing primary particles.
Antonis Dragoneas, Sergej Molleker, Oliver Appel, Andreas Hünig, Thomas Böttger, Markus Hermann, Frank Drewnick, Johannes Schneider, Ralf Weigel, and Stephan Borrmann
Atmos. Meas. Tech., 15, 5719–5742, https://doi.org/10.5194/amt-15-5719-2022, https://doi.org/10.5194/amt-15-5719-2022, 2022
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The ERICA is a specially designed aerosol particle mass spectrometer for in situ, real-time chemical composition analysis of aerosols. It can operate completely autonomously, in the absence of an instrument operator. Its design has enabled its operation under harsh conditions, like those experienced in the upper troposphere and lower stratosphere, aboard unpressurized high-altitude research aircraft. The instrument has successfully participated in several aircraft operations around the world.
Outi Meinander, Pavla Dagsson-Waldhauserova, Pavel Amosov, Elena Aseyeva, Cliff Atkins, Alexander Baklanov, Clarissa Baldo, Sarah L. Barr, Barbara Barzycka, Liane G. Benning, Bojan Cvetkovic, Polina Enchilik, Denis Frolov, Santiago Gassó, Konrad Kandler, Nikolay Kasimov, Jan Kavan, James King, Tatyana Koroleva, Viktoria Krupskaya, Markku Kulmala, Monika Kusiak, Hanna K. Lappalainen, Michał Laska, Jerome Lasne, Marek Lewandowski, Bartłomiej Luks, James B. McQuaid, Beatrice Moroni, Benjamin Murray, Ottmar Möhler, Adam Nawrot, Slobodan Nickovic, Norman T. O’Neill, Goran Pejanovic, Olga Popovicheva, Keyvan Ranjbar, Manolis Romanias, Olga Samonova, Alberto Sanchez-Marroquin, Kerstin Schepanski, Ivan Semenkov, Anna Sharapova, Elena Shevnina, Zongbo Shi, Mikhail Sofiev, Frédéric Thevenet, Throstur Thorsteinsson, Mikhail Timofeev, Nsikanabasi Silas Umo, Andreas Uppstu, Darya Urupina, György Varga, Tomasz Werner, Olafur Arnalds, and Ana Vukovic Vimic
Atmos. Chem. Phys., 22, 11889–11930, https://doi.org/10.5194/acp-22-11889-2022, https://doi.org/10.5194/acp-22-11889-2022, 2022
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High-latitude dust (HLD) is a short-lived climate forcer, air pollutant, and nutrient source. Our results suggest a northern HLD belt at 50–58° N in Eurasia and 50–55° N in Canada and at >60° N in Eurasia and >58° N in Canada. Our addition to the previously identified global dust belt (GDB) provides crucially needed information on the extent of active HLD sources with both direct and indirect impacts on climate and environment in remote regions, which are often poorly understood and predicted.
Joseph Girdwood, Warren Stanley, Chris Stopford, and David Brus
Atmos. Meas. Tech., 15, 2061–2076, https://doi.org/10.5194/amt-15-2061-2022, https://doi.org/10.5194/amt-15-2061-2022, 2022
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UAVs have great potential to be used for airborne measurements of cloud and aerosol properties, which are of particular importance due to the largely uncharacterised nature of such phenomena. However, since UAVs are a new tool in atmospheric physics expensive platform validation and characterisation of UAV-instrument combinations needs to be performed. This paper presents an evaluation of a fixed-wing UAV in combination with an instrument that measures cloud droplet diameter.
Andrea Pozzer, Simon F. Reifenberg, Vinod Kumar, Bruno Franco, Matthias Kohl, Domenico Taraborrelli, Sergey Gromov, Sebastian Ehrhart, Patrick Jöckel, Rolf Sander, Veronica Fall, Simon Rosanka, Vlassis Karydis, Dimitris Akritidis, Tamara Emmerichs, Monica Crippa, Diego Guizzardi, Johannes W. Kaiser, Lieven Clarisse, Astrid Kiendler-Scharr, Holger Tost, and Alexandra Tsimpidi
Geosci. Model Dev., 15, 2673–2710, https://doi.org/10.5194/gmd-15-2673-2022, https://doi.org/10.5194/gmd-15-2673-2022, 2022
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A newly developed setup of the chemistry general circulation model EMAC (ECHAM5/MESSy for Atmospheric Chemistry) is evaluated here. A comprehensive organic degradation mechanism is used and coupled with a volatility base model.
The results show that the model reproduces most of the tracers and aerosols satisfactorily but shows discrepancies for oxygenated organic gases. It is also shown that this model configuration can be used for further research in atmospheric chemistry.
Christoph Mahnke, Ralf Weigel, Francesco Cairo, Jean-Paul Vernier, Armin Afchine, Martina Krämer, Valentin Mitev, Renaud Matthey, Silvia Viciani, Francesco D'Amato, Felix Ploeger, Terry Deshler, and Stephan Borrmann
Atmos. Chem. Phys., 21, 15259–15282, https://doi.org/10.5194/acp-21-15259-2021, https://doi.org/10.5194/acp-21-15259-2021, 2021
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In 2017, in situ aerosol measurements were conducted aboard the M55 Geophysica in the Asian monsoon region. The vertical particle mixing ratio profiles show a distinct layer (15–18.5 km), the Asian tropopause aerosol layer (ATAL). The backscatter ratio (BR) was calculated based on the aerosol size distributions and compared with the BRs detected by a backscatter probe and a lidar aboard M55, and by the CALIOP lidar. All four methods show enhanced BRs in the ATAL altitude range (max. at 17.5 km).
Ralf Weigel, Christoph Mahnke, Manuel Baumgartner, Martina Krämer, Peter Spichtinger, Nicole Spelten, Armin Afchine, Christian Rolf, Silvia Viciani, Francesco D'Amato, Holger Tost, and Stephan Borrmann
Atmos. Chem. Phys., 21, 13455–13481, https://doi.org/10.5194/acp-21-13455-2021, https://doi.org/10.5194/acp-21-13455-2021, 2021
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In July and August 2017, the StratoClim mission took place in Nepal with eight flights of the M-55 Geophysica at up to 20 km in the Asian monsoon anticyclone. New particle formation (NPF) next to cloud ice was detected in situ by abundant nucleation-mode aerosols (> 6 nm) along with ice particles (> 3 µm). NPF was observed mainly below the tropopause, down to 15 % being non-volatile residues. Observed intra-cloud NPF indicates its importance for the composition in the tropical tropopause layer.
Ralf Weigel, Christoph Mahnke, Manuel Baumgartner, Antonis Dragoneas, Bärbel Vogel, Felix Ploeger, Silvia Viciani, Francesco D'Amato, Silvia Bucci, Bernard Legras, Beiping Luo, and Stephan Borrmann
Atmos. Chem. Phys., 21, 11689–11722, https://doi.org/10.5194/acp-21-11689-2021, https://doi.org/10.5194/acp-21-11689-2021, 2021
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In July and August 2017, eight StratoClim mission flights of the Geophysica reached up to 20 km in the Asian monsoon anticyclone. New particle formation (NPF) was identified in situ by abundant nucleation-mode aerosols (6–15 nm in diameter) with mixing ratios of up to 50 000 mg−1. NPF occurred most frequently at 12–16 km with fractions of non-volatile residues of down to 15 %. Abundance and productivity of observed NPF indicate its ability to promote the Asian tropopause aerosol layer.
Vinod Kumar, Julia Remmers, Steffen Beirle, Joachim Fallmann, Astrid Kerkweg, Jos Lelieveld, Mariano Mertens, Andrea Pozzer, Benedikt Steil, Marc Barra, Holger Tost, and Thomas Wagner
Atmos. Meas. Tech., 14, 5241–5269, https://doi.org/10.5194/amt-14-5241-2021, https://doi.org/10.5194/amt-14-5241-2021, 2021
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We present high-resolution regional atmospheric chemistry model simulations focused around Germany. We highlight the importance of spatial resolution of the model itself as well as the input emissions inventory and short-scale temporal variability of emissions for simulations. We propose a consistent approach for evaluating the simulated vertical distribution of NO2 using MAX-DOAS measurements while also considering its spatial sensitivity volume and change in sensitivity within this volume.
Sara Bacer, Sylvia C. Sullivan, Odran Sourdeval, Holger Tost, Jos Lelieveld, and Andrea Pozzer
Atmos. Chem. Phys., 21, 1485–1505, https://doi.org/10.5194/acp-21-1485-2021, https://doi.org/10.5194/acp-21-1485-2021, 2021
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We investigate the relative importance of the rates of both microphysical processes and unphysical correction terms that act as sources or sinks of ice crystals in cold clouds. By means of numerical simulations performed with a global chemistry–climate model, we assess the relevance of these rates at global and regional scales. This estimation is of fundamental importance to assign priority to the development of microphysics parameterizations and compare model output with observations.
Johannes Schneider, Ralf Weigel, Thomas Klimach, Antonis Dragoneas, Oliver Appel, Andreas Hünig, Sergej Molleker, Franziska Köllner, Hans-Christian Clemen, Oliver Eppers, Peter Hoppe, Peter Hoor, Christoph Mahnke, Martina Krämer, Christian Rolf, Jens-Uwe Grooß, Andreas Zahn, Florian Obersteiner, Fabrizio Ravegnani, Alexey Ulanovsky, Hans Schlager, Monika Scheibe, Glenn S. Diskin, Joshua P. DiGangi, John B. Nowak, Martin Zöger, and Stephan Borrmann
Atmos. Chem. Phys., 21, 989–1013, https://doi.org/10.5194/acp-21-989-2021, https://doi.org/10.5194/acp-21-989-2021, 2021
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During five aircraft missions, we detected aerosol particles containing meteoric material in the lower stratosphere. The stratospheric measurements span a latitude range from 15 to 68° N, and we find that at potential temperature levels of more than 40 K above the tropopause; particles containing meteoric material occur at similar abundance fractions across latitudes and seasons. We conclude that meteoric material is efficiently distributed between high and low latitudes by isentropic mixing.
Manuel Baumgartner, Ralf Weigel, Allan H. Harvey, Felix Plöger, Ulrich Achatz, and Peter Spichtinger
Atmos. Chem. Phys., 20, 15585–15616, https://doi.org/10.5194/acp-20-15585-2020, https://doi.org/10.5194/acp-20-15585-2020, 2020
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The potential temperature is routinely used in atmospheric science. We review its derivation and suggest a new potential temperature, based on a temperature-dependent parameterization of the dry air's specific heat capacity. Moreover, we compare the new potential temperature to the common one and discuss the differences which become more important at higher altitudes. Finally, we indicate some consequences of using the new potential temperature in typical applications.
Joseph Girdwood, Helen Smith, Warren Stanley, Zbigniew Ulanowski, Chris Stopford, Charles Chemel, Konstantinos-Matthaios Doulgeris, David Brus, David Campbell, and Robert Mackenzie
Atmos. Meas. Tech., 13, 6613–6630, https://doi.org/10.5194/amt-13-6613-2020, https://doi.org/10.5194/amt-13-6613-2020, 2020
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We present the design and validation of an unmanned aerial vehicle (UAV) equipped with a bespoke optical particle counter (OPC). This is used to monitor atmospheric particles, which have significant effects on our weather and climate. These effects are hard to characterise properly, partly because they occur in regions that are not commonly accessible to traditional instrumentation. Our new platform gives us the capability to access these regions.
Douglas Morrison, Ian Crawford, Nicholas Marsden, Michael Flynn, Katie Read, Luis Neves, Virginia Foot, Paul Kaye, Warren Stanley, Hugh Coe, David Topping, and Martin Gallagher
Atmos. Chem. Phys., 20, 14473–14490, https://doi.org/10.5194/acp-20-14473-2020, https://doi.org/10.5194/acp-20-14473-2020, 2020
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We provide conservative estimates of the concentrations of bacteria within transatlantic dust clouds, originating from the African continent. We observe significant seasonal differences in the overall concentrations of particles but no seasonal variation in the ratio between bacteria and dust. With bacteria contributing to ice formation at warmer temperatures than dust, our observations should improve the accuracy of climate models.
Edward Groot and Holger Tost
Atmos. Chem. Phys. Discuss., https://doi.org/10.5194/acp-2020-1142, https://doi.org/10.5194/acp-2020-1142, 2020
Publication in ACP not foreseen
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Sensitivities and variability of upper tropospheric flow (~10 km height) resulting immediately and as a direct consequence of (thunder)storm activity have been modeled in detail down to resolutions of 100–200 m and explored for different (organisation/) storm types. It is shown that the amount of water condensation explains much of emerging variability in upper atmospheric flow. Part of the effects on the nearby upper atmospheric flow is suggested to be explained by (organisation/) storm type.
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Short summary
For the balloon-borne detection of particles (diameter 0.4 < Dp < 40 µm), the Universal Cloud and Aerosol Sounding System (UCASS) was used, whose sample flow is determined by GPS-measured ascent rates. In flights, actual UCASS sample flows rarely match the ascent rates. Errors are minimised by real-time detection of the UCASS flows, e.g. by implementing a thermal flow sensor (TFS) within the UCASS. The TFSs were tested in flight and calibrated at up to 10 m s−1 and at variable angles of attack.
For the balloon-borne detection of particles (diameter 0.4 < Dp < 40 µm), the Universal Cloud...
