Atmos. Meas. techniques

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Combined list of the recent articles of the journal Atmospheric Measurement Techniques and the recent discussion forum Atmospheric Measurement Techniques Discussions
Updated: 1 day 5 hours ago

Classification of iron oxide aerosols by a single particle soot photometer using supervised machine learning

Fri, 03/22/2019 - 17:13
Classification of iron oxide aerosols by a single particle soot photometer using supervised machine learning
Kara D. Lamb
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2019-106,2019
Manuscript under review for AMT (discussion: open, 0 comments)
Recent atmospheric observations have indicated emissions of iron-oxide containing aerosols from anthropogenic sources could be 8× higher than previous estimates, leading models to underestimate their climate impact. Previous studies have shown the single particle soot photometer (SP2) can quantify the atmospheric abundance of these aerosols. Here, I explore a machine learning approach to improve SP2 detection, significantly reducing misclassifications of other aerosols as iron oxide aerosols.

Aerosol size distributions during the Atmospheric Tomography (ATom) mission: methods, uncertainties, and data products

Fri, 03/22/2019 - 17:13
Aerosol size distributions during the Atmospheric Tomography (ATom) mission: methods, uncertainties, and data products
Charles A. Brock, Christina Williamson, Agnieszka Kupc, Karl Froyd, Frank Erdesz, Nicholas Wagner, Matthews Richardson, Joshua P. Schwarz, Ru-Shan Gao, Joseph M. Katich, Pedro Campuzano-Jost, Benjamin A. Nault, Jason C. Schroder, Jose L. Jimenez, Bernadett Weinzierl, Maximillian Dollner, Thao Paul Bui, and Daniel M. Murphy
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2019-44,2019
Manuscript under review for AMT (discussion: open, 0 comments)
From 2016–2018 a NASA aircraft profiled the atmosphere from 150 m to ~ 12 km from the Arctic to the Antarctic over both the Pacific and Atlantic Oceans. This program, ATom, sought to sample atmospheric chemical composition to compare with global climate models. We describe the how measurements of particulate matter were made during ATom, and show that the instrument performance was excellent. Data from this project can be used with confidence to evaluate models and compare with satellites.

peakTree: A framework for structure-preserving radar Doppler spectra analysis

Fri, 03/22/2019 - 17:13
peakTree: A framework for structure-preserving radar Doppler spectra analysis
Martin Radenz, Johannes Bühl, Patric Seifert, Hannes Griesche, and Ronny Engelmann
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2019-76,2019
Manuscript under review for AMT (discussion: open, 0 comments)
Clouds frequently consist of multiple particle species. These particles may differ by phase (ice or liquid) or shape (needles, plates, aggregates, graupel) and thus also by fall velocity. When observed by cloud radars, these particle populations are usually represented by separated peaks in the Doppler spectrum. We separate these peaks and represent each of them as a node in a binary tree. The first application of this data structure helps to overcome deficits of currently available methods.

Better turbulence spectra from velocity–azimuth display scanning wind lidar

Thu, 03/21/2019 - 17:13
Better turbulence spectra from velocity–azimuth display scanning wind lidar
Felix Kelberlau and Jakob Mann
Atmos. Meas. Tech., 12, 1871-1888, https://doi.org/10.5194/amt-12-1871-2019, 2019
Lidars are devices that can measure wind velocities remotely from the ground. Their estimates are very accurate in the mean but wind speed fluctuations lead to measurement errors. The presented data processing methods mitigate several of the error causes: first, by making use of knowledge about the mean wind direction and, second, by determining the location of air packages and sensing them in the best moment. Both methods can be applied to existing wind lidars and results are very promising.

Addition of a fast GC to SIFT-MS for analyses of individual monoterpenes in mixtures

Thu, 03/21/2019 - 17:13
Addition of a fast GC to SIFT-MS for analyses of individual monoterpenes in mixtures
Michal Lacko, Nijing Wang, Kristýna Sovová, Pavel Pásztor, and Patrik Španěl
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2019-12,2019
Manuscript under review for AMT (discussion: open, 0 comments)
The soft chemical ionization analytical technique of selected ion flow tube mass spectrometry, SIFT-MS, was enhanced by fast GC pre-separation unit to quantify individual isomers. Experiments were carried out with two GC columns MXT-1 and MXT-Volatiles using two reagent ions H3O+ and NO+ on monoterpene samples (an artificial mixture and coniferous needles). Analyses of product ion ratios allowed quantification of multiple monoterpenes in partially separated chromatograms.

Cloud base height retrieval from multi-angle satellite data

Wed, 03/20/2019 - 17:13
Cloud base height retrieval from multi-angle satellite data
Christoph Böhm, Odran Sourdeval, Johannes Mülmenstädt, Johannes Quaas, and Susanne Crewell
Atmos. Meas. Tech., 12, 1841-1860, https://doi.org/10.5194/amt-12-1841-2019, 2019
The cloud base height (CBH) is important for air traffic, for describing the energy budget of the Earth and for other applications. Ground-based CBH measurements are only available for individual sites and mostly limited to land. Satellites are a powerful tool for global coverage. While the cloud top height is derived operationally, the derivation of CBH from space is more difficult as the clouds hide their base. Here, we present a method to retrieve the CBH from multi-angle satellite data.

Calibration of a 35 GHz airborne cloud radar: lessons learned and intercomparisons with 94 GHz cloud radars

Wed, 03/20/2019 - 17:13
Calibration of a 35 GHz airborne cloud radar: lessons learned and intercomparisons with 94 GHz cloud radars
Florian Ewald, Silke Groß, Martin Hagen, Lutz Hirsch, Julien Delanoë, and Matthias Bauer-Pfundstein
Atmos. Meas. Tech., 12, 1815-1839, https://doi.org/10.5194/amt-12-1815-2019, 2019
This study gives a summary of lessons learned during the absolute calibration of the airborne, high-power Ka-band cloud radar HAMP MIRA on board the German research aircraft HALO. The first part covers the internal calibration of the instrument where individual instrument components are characterized in the laboratory. In the second part, the internal calibration is validated with external reference sources like the ocean surface backscatter and different air- and spaceborne cloud radars.

Using collision-induced dissociation to constrain sensitivity of ammonia chemical ionization mass spectrometry (NH4+ CIMS) to oxygenated volatile organic compounds

Wed, 03/20/2019 - 17:13
Using collision-induced dissociation to constrain sensitivity of ammonia chemical ionization mass spectrometry (NH4+ CIMS) to oxygenated volatile organic compounds
Alexander Zaytsev, Martin Breitenlechner, Abigail R. Koss, Christopher Y. Lim, James C. Rowe, Jesse H. Kroll, and Frank N. Keutsch
Atmos. Meas. Tech., 12, 1861-1870, https://doi.org/10.5194/amt-12-1861-2019, 2019
We present the development of a chemical ionization mass spectrometer which can be operated with either ammonium (NH4+) or hydronium (H3O+) as the reagent ion. We describe a mass spectrometric voltage scanning procedure based on collision-induced dissociation that allows us to determine the stability of detected ammonium–organic ions and hence constrain the sensitivity of the instrument to a wide range of organic compounds that cannot be calibrated directly.

3 + 2 + X: What is the most useful depolarization input for retrieving microphysical properties of non-spherical particles from lidar measurements by assuming spheroidal particle shapes?

Wed, 03/20/2019 - 17:13
3 + 2 + X: What is the most useful depolarization input for retrieving microphysical properties of non-spherical particles from lidar measurements by assuming spheroidal particle shapes?
Matthias Tesche, Alexei Kolgotin, Moritz Haarig, Sharon P. Burton, Richard A. Ferrare, Chris A. Hostetler, and Detlef Müller
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2019-71,2019
Manuscript under review for AMT (discussion: open, 0 comments)
Today, few lidars are capable of triple-wavelengths particle linear depolarisation ratio (PLDR) measurements. This study is the first systematic investigation of the effect of different choice of PLDR input on the inversion of lidar measurements of mineral dust and dusty mixtures using light-scattering by randomly oriented spheroids. We provide recommendations on the most suitable input parameters for use with the applied methodology based on a relational assessment of the inversion output.

Recent improvements of Long-Path DOAS measurements: impact on accuracy and stability of short-term and automated long-term observations

Wed, 03/20/2019 - 17:13
Recent improvements of Long-Path DOAS measurements: impact on accuracy and stability of short-term and automated long-term observations
Jan-Marcus Nasse, Philipp G. Eger, Denis Pöhler, Stefan Schmitt, Udo Frieß, and Ulrich Platt
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2019-69,2019
Manuscript under review for AMT (discussion: open, 0 comments)
We present several changes to the setup of Long-Path Differential Optical Absorption Spectroscopy (LP-DOAS) instruments including the application of a laser-driven light source, a modified coupling of the measurement signal between components, improved stray-light suppression, and better signal homogenisation measures. These changes reduce detection limits of typical trace gas species by a factor of 3–4 compared to previous setups and enabled automated long-term observations in Antarctica.

A Novel Approach for Simple Statistical Analysis of High-Resolution Mass Spectra

Wed, 03/20/2019 - 17:13
A Novel Approach for Simple Statistical Analysis of High-Resolution Mass Spectra
Yanjun Zhang, Otso Peräkylä, Chao Yan, Liine Heikkinen, Mikko Äijälä, Kaspar R. Daellenbach, Qiaozhi Zha, Matthieu Riva, Olga Garmash, Heikki Junninen, Pentti Paatero, Douglas Worsnop, and Mikael Ehn
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2019-59,2019
Manuscript under review for AMT (discussion: open, 0 comments)
Recent advancements in atmospheric mass spectrometry provide huge amounts of new information, but at the same time present considerable challenges for the data analysis, for example, in high-resolution peak identification and separation. To address these problems, this study presents a simple and novel method, which succeeds in analyzing both synthetic and ambient datasets. We believe it will become a powerful approach in the data analysis of mass spectra.

Adaptation and performance assessment of a quantum and interband cascade laser spectrometer for simultaneous airborne in situ observation of CH4, C2H6, CO2, CO and N2O

Tue, 03/19/2019 - 17:13
Adaptation and performance assessment of a quantum and interband cascade laser spectrometer for simultaneous airborne in situ observation of CH4, C2H6, CO2, CO and N2O
Julian Kostinek, Anke Roiger, Kenneth J. Davis, Colm Sweeney, Joshua P. DiGangi, Yonghoon Choi, Bianca Baier, Frank Hase, Jochen Groß, Maximilian Eckl, Theresa Klausner, and André Butz
Atmos. Meas. Tech., 12, 1767-1783, https://doi.org/10.5194/amt-12-1767-2019, 2019
We demonstrate the successful adaption of a laser-based spectrometer for airborne in situ trace gas measurements. The modified instrument allows for precise and simultaneous airborne observation of five climatologically relevant gases. We further report on instrument performance during a first field deployment over the eastern and central USA.

The Mainz profile algorithm (MAPA)

Tue, 03/19/2019 - 17:13
The Mainz profile algorithm (MAPA)
Steffen Beirle, Steffen Dörner, Sebastian Donner, Julia Remmers, Yang Wang, and Thomas Wagner
Atmos. Meas. Tech., 12, 1785-1806, https://doi.org/10.5194/amt-12-1785-2019, 2019

The Mainz profile algorithm (MAPA) derives vertical profiles of aerosol extinction and trace gas concentrations from MAX-DOAS measurements of slant column densities under multiple elevation angles. This paper presents (a) a detailed description of the MAPA (v0.98), (b) results for the CINDI-2 campaign, and (c) sensitivity studies on the impact of a priori assumptions such as flag thresholds.

Like previous profile retrieval schemes developed at MPIC, MAPA is based on a profile parameterization combining box profiles, which also might be lifted, and exponential profiles. But in contrast to previous inversion schemes based on least-square fits, MAPA follows a Monte Carlo approach for deriving those profile parameters yielding best match to the MAX-DOAS observations. This is much faster and directly provides physically meaningful distributions of profile parameters. In addition, MAPA includes an elaborated flagging scheme for the identification of questionable or dubious results.

The AODs derived with MAPA for the CINDI-2 campaign show good agreement with AERONET if a scaling factor of 0.8 is applied for O4, and the respective NO2 and HCHO surface mixing ratios match those derived from coincident long-path DOAS measurements. MAPA results are robust with respect to modifications of the a priori MAPA settings within plausible limits.

Laser frequency stabilization based on a universal sub-Doppler NICE-OHMS instrumentation for the potential application in atmospheric lidar

Tue, 03/19/2019 - 17:13
Laser frequency stabilization based on a universal sub-Doppler NICE-OHMS instrumentation for the potential application in atmospheric lidar
Yueting Zhou, Jianxin Liu, Songjie Guo, Gang Zhao, Weiguang Ma, Zhensong Cao, Lei Dong, Lei Zhang, Wangbao Yin, Yongqian Wu, Lianxuan Xiao, Ove Axner, and Suotang Jia
Atmos. Meas. Tech., 12, 1807-1814, https://doi.org/10.5194/amt-12-1807-2019, 2019
A relative weak transition of target gas is often selected to ensure a large optical depth in atmospheric lidar. Meanwhile, the laser frequency should be stabilized to the line center for valid detection. Sub-Doppler spectroscopy is the most suitable reference to obtain a high-quality frequency stabilization. In this paper, a novel universal sD NICE-OHMS instrumentation based on a f-SSM is reported, which has a potential application in the atmospheric lidar for different types of lasers.

Versatile Aerosol Concentration Enrichment System (VACES) operating as a Cloud Condensation Nuclei (CCN) concentrator. Development and laboratory characterization

Tue, 03/19/2019 - 17:13
Versatile Aerosol Concentration Enrichment System (VACES) operating as a Cloud Condensation Nuclei (CCN) concentrator. Development and laboratory characterization
Carmen Dameto de España, Gerhard Steiner, Harald Schuh, Constantinos Sioutas, and Regina Hitzenberger
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2019-75,2019
Manuscript under review for AMT (discussion: open, 0 comments)
The ability of atmospheric aerosol particles to act as cloud condensation nuclei (CCN) depends on many factors, including particle size, chemical composition, and meteorological conditions. To expand our knowledge on CCN, it is essential to understand the factors leading to CCN activation. For this purpose a versatile aerosol concentrator enrichment system (VACES) has been modified to select CCN at different supersaturations. The VACES enables to sample CCN particles without altering their chemical and physical properties. The redesigned VACES enriches CCN particles by first passing the aerosol flow to a new saturator and then to a condenser. The activated particles are concentrated by an inertial virtual impactor, and then can be returned to their original size by diffusion-drying. For the calibration, the saturator temperature was fixed at 52 °C and the condenser temperature range was altered from 5 °C to 25 °C to obtain activation curves for NaCl particles of different sizes. Critical water vapour supersaturations can be calculated using the 50 % cutpoint of these curves. Calibration results have also shown that CCN concentrations can be enriched by a factor of approx. 17, which is in agreement with the experimentally determined enrichment factor of the original VACES. The advantage of the re-designed VACES over conventional CCN counters (both static and continuous flow instruments) lies in the substantial enrichment of activated CCN which facilitates further chemical analysis.

True eddy accumulation trace gas flux measurements: proof-of-concept

Mon, 03/18/2019 - 18:24
True eddy accumulation trace gas flux measurements: proof-of-concept
Lukas Siebicke and Anas Emad
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2018-460,2019
Manuscript under review for AMT (discussion: open, 0 comments)
We present the proof-of-concept for an innovative flux measurement method able to quantify the land-atmosphere exchange of a large number of greenhouse gases and trace gases, which are important for air quality and atmospheric composition. Key to the success was an innovative high-speed air sampling system. The new flux measurement method performed very well compared to the established alternative. Finally, we suggest new features and applications of the technique.

The importance of particle size distribution shape for triple-frequency radar retrievals of the morphology of snow

Mon, 03/18/2019 - 18:24
The importance of particle size distribution shape for triple-frequency radar retrievals of the morphology of snow
Shannon L. Mason, Robin J. Hogan, Christopher D. Westbrook, Stefan Kneifel, and Dmitri Moisseev
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2019-100,2019
Manuscript under review for AMT (discussion: open, 0 comments)
The mass contents of snowflakes are critical to remotely-sensed estimates of snowfall. The signatures of snow measured at three radar frequencies can distinguish fluffy, fractal snowflakes from dense and more homogeneous rimed snow. However, we show that the shape of the particle size spectrum also has a significant impact on triple-frequency radar signatures, and must be accounted for when making triple-frequency radar estimates of snow that include variations in particle structure and density.

Validation, comparison, and integration of GOCI, AHI, MODIS, MISR, and VIIRS aerosol optical depth over East Asia during the 2016 KORUS-AQ campaign

Mon, 03/18/2019 - 18:24
Validation, comparison, and integration of GOCI, AHI, MODIS, MISR, and VIIRS aerosol optical depth over East Asia during the 2016 KORUS-AQ campaign
Myungje Choi, Hyunkwang Lim, Jhoon Kim, Seoyoung Lee, Thomas F. Eck, Brent N. Holben, Michael J. Garay, Edward J. Hyer, and Pablo E. Saide
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2019-46,2019
Manuscript under review for AMT (discussion: open, 0 comments)
Satellite-based aerosol optical depth (AOD) products have been improved continuously and available from multiple low-Earth-orbit sensors such as MODIS, MISR and VIIRS and geostationary sensors such as GOCI and AHI over East Asia. These multi-satellite AOD products are validated, intercompared, analyzed and integrated to understand different characteristics such as quality and spatio-temporal coverage focused on several aerosol transportation cases during 2016 KORUS-AQ campaign.

Determination of Ice Water Content (IWC) in tropical convective clouds from X-band dual-polarization airborne radar

Mon, 03/18/2019 - 18:24
Determination of Ice Water Content (IWC) in tropical convective clouds from X-band dual-polarization airborne radar
Cuong M. Nguyen, Mengistu Wolde, and Alexei Korolev
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2019-62,2019
Manuscript under review for AMT (discussion: open, 0 comments)
This paper presents a method using Kdp and Zdr from a side-looking X-band dual-polarization airborne radar to improve high ice water content (HIWC) (up to 3.5 g m−3) retrieval in tropical mesoscale convective systems (MCS). The proposed method shows an improvement of 15 % in estimation bias compared to the method using Kdp alone. Accurate detection and estimation of HIWC in MCSs are critical for reducing hazards caused by the ingestion of ice particles into the engines of commercial aircraft.

A bulk-mass-modeling-based method for retrieving particulate matter pollution using CALIOP observations

Mon, 03/18/2019 - 17:13
A bulk-mass-modeling-based method for retrieving particulate matter pollution using CALIOP observations
Travis D. Toth, Jianglong Zhang, Jeffrey S. Reid, and Mark A. Vaughan
Atmos. Meas. Tech., 12, 1739-1754, https://doi.org/10.5194/amt-12-1739-2019, 2019
An innovative method is presented for deriving particulate matter (PM) concentrations using CALIOP measurements. Deviating from conventional approaches of relying on passive satellite column-integrated aerosol measurements, PM concentrations are derived from near-surface CALIOP measurements through a bulk-mass-modeling method. This proof-of-concept study shows that, while limited in spatial and temporal coverage, CALIOP exhibits reasonable skill for PM applications.

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