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The formation and impact of ice crystals in clouds remain a challenge to understand and thus to be predicted in models. In recent years, measurements of ice-nucleating particles (INPs) in ambient air have become more frequent, using... more
The formation and impact of ice crystals in clouds remain a challenge to understand and thus to be predicted in models. In recent years, measurements of ice-nucleating particles (INPs) in ambient air have become more frequent, using well-established and novel techniques such as mobile cloud chambers and filter-based freezing assays. To assure that these techniques are working as intended, validation and intercomparison measurements are required. This is especially relevant due to ongoing efforts for the establishment of INP monitoring networks at the European level (ACTRIS; Aerosol, Clouds and Trace Gases Research Infrastructure) and in the United States (ARM; Atmospheric Radiation Measurement).Here we present results from PICNIC (The Puy de Dôme ICe Nucleation Intercomparison Campaign), conducted at a mountain site in Central France (1465 m a.s.l.) in October 2018. INP concentrations relevant in the mixed-phase cloud regime were determined using three online INP techniques (Colorad...
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Mechanisms behind the phenomenon of Arctic amplification are widely discussed. To contribute to this debate, the (AC)3 project was established in 2016 (www.ac3-tr.de/). It comprises modeling and data analysis efforts as well as... more
Mechanisms behind the phenomenon of Arctic amplification are widely discussed. To contribute to this debate, the (AC)3 project was established in 2016 (www.ac3-tr.de/). It comprises modeling and data analysis efforts as well as observational elements. The project has assembled a wealth of ground-based, airborne, shipborne, and satellite data of physical, chemical, and meteorological properties of the Arctic atmosphere, cryosphere, and upper ocean that are available for the Arctic climate research community. Short-term changes and indications of long-term trends in Arctic climate parameters have been detected using existing and new data. For example, a distinct atmospheric moistening, an increase of regional storm activities, an amplified winter warming in the Svalbard and North Pole regions, and a decrease of sea ice thickness in the Fram Strait and of snow depth on sea ice have been identified. A positive trend of tropospheric bromine monoxide (BrO) column densities during polar sp...
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International audienc
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Eight atmospheric reanalyses were compared against observed vertical profiles of temperature, specific humidity and wind speed collected by two research aircraft in February–March 2010 in the Antarctic Peninsula region. These data offered... more
Eight atmospheric reanalyses were compared against observed vertical profiles of temperature, specific humidity and wind speed collected by two research aircraft in February–March 2010 in the Antarctic Peninsula region. These data offered a rare possibility to validate reanalyses against independent in situ data which have not been assimilated into the reanalyses. The reanalyses had generally too moist profiles with too low wind speeds, but otherwise the errors in the reanalyses had large spatial differences. On the eastern side of the peninsula, the near‐surface temperatures were largely overestimated. None of the reanalyses outperformed the others in all variables, at all altitudes and on both sides of the peninsula. Generally, NCEP‐CFSR and MERRA had the smallest errors in temperature profiles, JRA‐55 had marginally the most accurate specific humidity profiles and NCEP‐CFSR had the best wind profiles. The reanalyses were coherent, although biased, on the western side of the Antar...
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This dataset contains the model configuration files and selected output data of the large-eddy simulation experiments as described in the publication: "The Impact of CCN Concentrations on the Thermodynamic and Turbulent State of... more
This dataset contains the model configuration files and selected output data of the large-eddy simulation experiments as described in the publication: "The Impact of CCN Concentrations on the Thermodynamic and Turbulent State of Arctic Mixed-Phase Clouds".
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The Arctic Cloud Observations Using Airborne Measurements during Polar Day (ACLOUD) campaign was carried out North-West of Svalbard (Norway) between 23 May 26 June 2017. The objective of ACLOUD was to study Arctic boundary layer and... more
The Arctic Cloud Observations Using Airborne Measurements during Polar Day (ACLOUD) campaign was carried out North-West of Svalbard (Norway) between 23 May 26 June 2017. The objective of ACLOUD was to study Arctic boundary layer and mid-level clouds and their role in Arctic Amplification. Two research aircraft (Polar 5 and 6) jointly performed 22 research flights over the transition zone between open ocean and closed sea ice. Both aircraft were equipped with identical 5 instrumentation for measurements of basic meteorological parameters, as well as for turbulent and and radiative energy fluxes. In addition, on Polar 5 active and passive remote sensing instruments were installed, while Polar 6 operated in situ instruments to characterize cloud and aerosol particles as well as trace gases. A detailed overview of the specifications, data processing, and data quality is provided here. It is shown , that the scientific analysis of the ACLOUD data benefits from the coordinated operation o...
Stable Water Isotopologue data collected during HCCT-2010, supplement to: Spiegel, Johanna K; Aemisegger, F; Scholl, M; Wienhold, F G; Collett, Tim S; Lee, T; van Pinxteren, Dominik; Mertes, Stephan; Tilgner, A; Herrmann, H; Werner, R A; Buchmann, N; Eugster, Werner (2012): Temporal evolution of ...more
Cloud samples for the isotopic analysis were collected in the framework of the Hill Cap Cloud Thuringia 2010 (HCCT-2010) campaign on Schmücke (50° 39'N/ 10° 46'E, 937 m a.s.l.; Germany) in September and October 2010 with a... more
Cloud samples for the isotopic analysis were collected in the framework of the Hill Cap Cloud Thuringia 2010 (HCCT-2010) campaign on Schmücke (50° 39'N/ 10° 46'E, 937 m a.s.l.; Germany) in September and October 2010 with a three-stage Caltech Active Strand Cloudwater Collector (CASCC) during 13 different cloud events with a temporal resolution of 1 to 3 hours. In a first step, we ensured that no additional fractionation occurred during sampling with the CASCC. The d values of the three sizes classes of the CASCC (4 µm to 16 µm, 16 µm to 22 µm and >22 µm) did not differ significantly, revealing that the cloud droplets of different sizes quickly equilibrate their delta value with the one of the surrounding vapor. delta values in the cloud droplets varied from -77 per mil to -15 per mil in d2H and from -12.1 per mil to -3.9 per mil in d18O and were fitted by d2H =7.8*d18O +13*10**-3. delta values decreased with temperature as well as towards the end of the campaign, represen...
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This dataset contains the model configuration files and selected output data of the large-eddy simulation experiments as described in the publication: "Aerosol-cloud-turbulence interactions in well-coupled Arctic<br> boundary... more
This dataset contains the model configuration files and selected output data of the large-eddy simulation experiments as described in the publication: "Aerosol-cloud-turbulence interactions in well-coupled Arctic<br> boundary layers over open water"
The Arctic CLoud Observations Using airborne measurements during polar Day (ACLOUD) campaign was carried out north-west of Svalbard (Norway) between 23 May and 6 June 2017. The objective of ACLOUD was to study Arctic boundary layer and... more
The Arctic CLoud Observations Using airborne measurements during polar Day (ACLOUD) campaign was carried out north-west of Svalbard (Norway) between 23 May and 6 June 2017. The objective of ACLOUD was to study Arctic boundary layer and mid-level clouds and their role in Arctic amplification. Two research aircraft (Polar 5 and 6) jointly performed 22 research flights over the transition zone between open ocean and closed sea ice. Both aircraft were equipped with identical instrumentation for measurements of basic meteorological parameters, as well as for turbulent and radiative energy fluxes. In addition, on Polar 5 active and passive remote sensing instruments were installed, while Polar 6 operated in situ instruments to characterize cloud and aerosol particles as well as trace gases. A detailed overview of the specifications, data processing, and data quality is provided here. It is shown that the scientific analysis of the ACLOUD data benefits from the coordinated operation of bot...
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Felduntersuchungen von Budgets und Konversionen organischer Partikelinhaltsstoffe in troposphärischen Wolkenprozessen (FEBUKO): Projektabschlussbericht ; Teilprojekte: IfT-1: Physiko-chemische Charakterisierung von Luft, Partikeln und Wolkenwasser in Wolkenexperimenten; IfT-2: Phasenaufteilung vo...more
[no abstract available]
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Airborne observations over the Amazon Basin showed high aerosol particle concentrations in the upper troposphere (UT) between 8 and 15 km altitude, with number densities (normalized to standard temperature and pressure) often... more
Airborne observations over the Amazon Basin showed high aerosol particle concentrations in the upper troposphere (UT) between 8 and 15 km altitude, with number densities (normalized to standard temperature and pressure) often exceeding those in the planetary boundary layer (PBL) by one or two orders of magnitude. The measurements were made during the German-Brazilian cooperative aircraft campaign ACRIDICON-CHUVA on the German High Altitude and Long Range Research Aircraft (HALO). The campaign took place in September/October 2014, with the objective of studying tropical deep convective clouds over the Amazon rainforest and their interactions with atmospheric trace gases, aerosol particles, and atmospheric radiation. <br><br> Aerosol enhancements were observed consistently on all flights during which the UT was probed, using several aerosol metrics, including condensation nuclei (CN) and cloud condensation nuclei (CCN) number concentrations and chemical species mass...
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In this study we show how size-resolved measurements of aerosol particles and cloud condensation nuclei (CCN) can be used to characterize the supersaturation of water vapor in a cloud. The method was developed and applied during the... more
In this study we show how size-resolved measurements of aerosol particles and cloud condensation nuclei (CCN) can be used to characterize the supersaturation of water vapor in a cloud. The method was developed and applied during the ACRIDICON-Zugspitze campaign (17 September to 4 October 2012) at the high-Alpine research station Schneefernerhaus (German Alps, 2650 m a.s.l.). Number size distributions of total and interstitial aerosol particles were measured with a scanning mobility particle sizer (SMPS), and size-resolved CCN efficiency spectra were recorded with a CCN counter system operated at different supersaturation levels. <br><br> During the evolution of a cloud, aerosol particles are exposed to different supersaturation levels. We outline and compare different estimates for the lower and upper bounds (<i>S</i><sub>low</sub>, <i>S</i><sub>high</sub>) and the average value (<i>S</i><sub>avg</sub&g...
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In this paper results are presented of ground-based fog microphysical measurements obtained during the CHEMDROP experiment in the Po Valley (Northern Italy) in November 1994. Altogether about 85 hours of drop microphysical data are... more
In this paper results are presented of ground-based fog microphysical measurements obtained during the CHEMDROP experiment in the Po Valley (Northern Italy) in November 1994. Altogether about 85 hours of drop microphysical data are analyzed. At the beginning of the experiment a comparison of some of the different microphysical instruments, operated during the experiment, was performed. It has revealed some differences between the Liquid Water Content LWC measured by Particle Volume Monitors (PVMs), and by several Forward Scattering Spectrometer Probes (FSSPs). Possible explanations for the discrepancies are discussed. The FSSP derived drop size distributions (number and mass) were parameterized in terms of log-normal distributions. The statistical analysis of the fittings has shown that the overwhelming majority of the drop mass size distributions was characterized by a bimodal shape. The most frequent values of the mode parameters (median diameter, geometric standard deviation) are given in Table 3 of this paper. An investigation of the temporal evolution of the drop size distribution revealed two typical phases of fog formation. In the first step both modes of the drop mass size distribution increase more or less uniform, whereas in the second phase the large drop mode drastically rises. Furthermore, the second phase is characterized by quasi-periodic oscillations in nearly all mode parameters of the drop size distribution with a period between ten and 15 minutes. In the last part of the paper the frequent occurrence of drizzle within the fog was studied by comparing the measurements with respective model calculations.
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Abstract will follow upon submission to the journal.
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A method using ion chromatography coupled to high-resolution Orbitrap mass spectrometry was developed to quantify highly-polar organic compounds in aqueous filter extracts of atmospheric particles. In total, 43 compounds, including... more
A method using ion chromatography coupled to high-resolution Orbitrap mass spectrometry was developed to quantify highly-polar organic compounds in aqueous filter extracts of atmospheric particles. In total, 43 compounds, including short-chain carboxylic acids, terpene-derived acids, organosulfates, and inorganic anions were separated within 33 min by a KOH gradient. Ionization by electrospray was maximized by adding 100 μL min-1 isopropanol as post-column solvent and optimizing the ion source settings. Detection limits (S/N ≥ 3) were in the range of 0.075-25 μg L-1 and better than previously reported for 22 compounds. Recoveries of extraction typically range from 85-117 %. The developed method was applied to three ambient samples, including two arctic flight samples, and one sample from Melpitz, a continental backround research site. A total of 32 different compounds were identified for all samples. From the arctic flight samples, organic tracers could be quantified for the first t...
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Programme, H2020-INFRADEV-2016-2017, Grant Agreement number: 739530 Deliverable D5.1: Documentation on technical concepts and requirements for ACTRIS Observational Platforms Authors: Ulla Wandinger, Arnoud Apituley, Thomas Blumenstock,... more
Programme, H2020-INFRADEV-2016-2017, Grant Agreement number: 739530 Deliverable D5.1: Documentation on technical concepts and requirements for ACTRIS Observational Platforms Authors: Ulla Wandinger, Arnoud Apituley, Thomas Blumenstock, Nicolas Bukowiecki, Jean-Pierre Cammas, Paul Connolly, Martine De Mazière, Bart Dils, Markus Fiebig, Evelyn Freney, Martin Gallagher, Sophie Godin-Beekmann, Philippe Goloub, Martin Gysel, Martial Haeffelin, Frank Hase, Markus Hermann, Hartmut Herrmann, Tuija Jokinen, Mika Komppula, Dagmar Kubistin, Bavo Langerock, Heikki Lihavainen, Nikos Mihalopoulos, Paolo Laj, Cathrine Lund Myhre, Emmanuel Mahieu, Stephan Mertes, Ottmar Möhler, Lucia Mona, Doina Nicolae, Ewan O’Connor, Mathias Palm, Gelsomina Pappalardo, Andrea Pazmino, Tuukka Petäjä, Sabine Philippin, Christian Plass-Duelmer, Bernhard Pospichal, Jean-Philippe Putaud, Stefan Reimann, Franz Rohrer, Herman Russchenberg, Stéphane Sauvage, Karine Sellegri, Rainer Steinbrecher, Frank Stratmann, Ralf Sus...
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The Midlatitude Cirrus experiment (ML-CIRRUS) deployed the High Altitude and Long Range Research Aircraft (HALO) to obtain new insights into nucleation, life cycle, and climate impact of natural cirrus and aircraft-induced contrail... more
The Midlatitude Cirrus experiment (ML-CIRRUS) deployed the High Altitude and Long Range Research Aircraft (HALO) to obtain new insights into nucleation, life cycle, and climate impact of natural cirrus and aircraft-induced contrail cirrus. Direct observations of cirrus properties and their variability are still incomplete, currently limiting our understanding of the clouds’ impact on climate. Also, dynamical effects on clouds and feedbacks are not adequately represented in today’s weather prediction models. Here, we present the rationale, objectives, and selected scientific highlights of ML-CIRRUS using the G-550 aircraft of the German atmospheric science community. The first combined in situ–remote sensing cloud mission with HALO united state-of-the-art cloud probes, a lidar and novel ice residual, aerosol, trace gas, and radiation instrumentation. The aircraft observations were accompanied by remote sensing from satellite and ground and by numerical simulations. In spring 2014, HA...
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ABSTRACT
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This data set consists of in-situ measurements of arctic ambient aerosol particle (outside cloud) and cloud particle residual (inside cloud) aerosol properties observed during the ACLOUD campaign which took place during May/June 2017,... more
This data set consists of in-situ measurements of arctic ambient aerosol particle (outside cloud) and cloud particle residual (inside cloud) aerosol properties observed during the ACLOUD campaign which took place during May/June 2017, which was part of the AC3 project. These measurements were made using the CVI inlet and PSAP, CPC and UHSAS aerosol instruments of the Leibniz Institute for Tropospheric Research (TROPOS) in Leipzig, Germany. The CVI flag 0 or 1 denotes ambient aerosol or cloud particle residual measurements, respectively, accomplished by a change in the sampling behavior of the CVI inlet. Measurements just after switching from one mode to another should be treated with caution, especially for the absorption coefficient values which have a time resolution of 30 sec. The given data sets are already corrected for the CVI enrichment factor, which should also be applied for measurements of other groups behind the CVI. Another correction for cloud particle residual measurements only is the CVI aspiration and sampling efficiency, which can be inferred from the comparison with the in-situ cloud particle measurements. Contact the PI and contact person Stephan Mertes for more information. Use only measurement data after takeoff and before landing of the Polar 6 aircraft. CVI inlet heating broke 2017-06-14T15:43:08, so that inlet freezing could have been occurred thereafter. Those periods are tried to identified and data deleted. The UHSAS two dimensional size distribution data is given in size bin diameter Dp (nm) in the header and the dN/dlogDp (cm-3 nm-1) value starting from column 13. The UHSAS instrument broke 2017-06-17T11:41:12. From this point in time no size distribution data are provided anymore. There is one file per flight. A detailed description of the data processing will be done in an upcoming data paper.