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: 8 hours 4 min ago

Simulating precipitation radar observations from a geostationary satellite

Fri, 07/19/2019 - 18:00
Simulating precipitation radar observations from a geostationary satellite
Atsushi Okazaki, Takumi Honda, Shunji Kotsuki, Moeka Yamaji, Takuji Kubota, Riko Oki, Toshio Iguchi, and Takemasa Miyoshi
Atmos. Meas. Tech., 12, 3985-3996, https://doi.org/10.5194/amt-12-3985-2019, 2019
The JAXA is surveying the feasibility of a potential satellite mission equipped with a precipitation radar on a geostationary orbit, as a successor of the GPM Core Observatory. We investigate what kind of observation data will be available from the radar using simulation techniques. Although the quality of the observation depends on the radar specifications and the position of precipitation systems, the results demonstrate that it would be possible to obtain three-dimensional precipitation data.

A geometry-dependent surface Lambertian-equivalent reflectivity product for UV–Vis retrievals – Part 1: Evaluation over land surfaces using measurements from OMI at 466 nm

Fri, 07/19/2019 - 18:00
A geometry-dependent surface Lambertian-equivalent reflectivity product for UV–Vis retrievals – Part 1: Evaluation over land surfaces using measurements from OMI at 466 nm
Wenhan Qin, Zachary Fasnacht, David Haffner, Alexander Vasilkov, Joanna Joiner, Nickolay Krotkov, Bradford Fisher, and Robert Spurr
Atmos. Meas. Tech., 12, 3997-4017, https://doi.org/10.5194/amt-12-3997-2019, 2019
Satellite observations depend on Sun and view angles due to anisotropy of the Earth's atmosphere and surface reflection. But most of the ultraviolet and visible cloud, aerosol, and trace-gas algorithms utilize surface reflectivity databases that do not account for surface anisotropy. We create a surface database using the GLER concept which adequately accounts for surface anisotropy, validate it with independent satellite data, and provide a simple implementation to the current algorithms.

Comparison between the assimilation of IASI Level 2 ozone retrievals and Level 1 radiances in a chemical transport model

Fri, 07/19/2019 - 18:00
Comparison between the assimilation of IASI Level 2 ozone retrievals and Level 1 radiances in a chemical transport model
Emanuele Emili, Brice Barret, Eric Le Flochmoën, and Daniel Cariolle
Atmos. Meas. Tech., 12, 3963-3984, https://doi.org/10.5194/amt-12-3963-2019, 2019
We examine the differences between assimilating ozone profiles retrieved from IASI or the corresponding infrared spectra in a chemical transport model. This allows the impact of the retrieval's prior information on ozone reanalyses to be quantified. We found that significant differences can arise between the two approaches, depending on the latitude. An improved O3 variability is obtained assimilating IASI radiances directly. The implications for coupled Earth system models are discussed.

Rayleigh wind retrieval for the ALADIN airborne demonstrator of the Aeolus mission using simulated response calibration

Fri, 07/19/2019 - 18:00
Rayleigh wind retrieval for the ALADIN airborne demonstrator of the Aeolus mission using simulated response calibration
Xiaochun Zhai, Uwe Marksteiner, Fabian Weiler, Christian Lemmerz, Oliver Lux, Benjamin Witschas, and Oliver Reitebuch
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2019-274,2019
Manuscript under review for AMT (discussion: open, 0 comments)
An airborne prototype called A2D was developed for validating the Aeolus measurement principle based on realistic atmospheric signals. However, the atmospheric and instrumental variability currently limit the reliability and repeatability of the measured Rayleigh response calibration (MRRC), which is a prerequisite for accurate wind retrieval. A procedure for a simulated Rayleigh response calibration is developed and presented to resolve these limitations of the A2D Rayleigh channel MRRC.

A practical information-centered technique to remove a priori information from lidar optimal-estimation-method retrievals

Thu, 07/18/2019 - 18:00
A practical information-centered technique to remove a priori information from lidar optimal-estimation-method retrievals
Ali Jalali, Shannon Hicks-Jalali, Robert J. Sica, Alexander Haefele, and Thomas von Clarmann
Atmos. Meas. Tech., 12, 3943-3961, https://doi.org/10.5194/amt-12-3943-2019, 2019
This paper builds upon the work in von Clarmann and Grabowski (2007) concerning the a priori profile influence in the optimal estimation method applied to active remote sensing measurements, with examples given for lidar retrievals of temperature and water vapor mixing ratio. The optimal estimation method is a new technique for many active remote sensing researchers. This study gives insight into understanding the effect on retrievals of the a priori information.

Inversion of multiangular polarimetric measurements over open and coastal ocean waters: a joint retrieval algorithm for aerosol and water-leaving radiance properties

Wed, 07/17/2019 - 18:00
Inversion of multiangular polarimetric measurements over open and coastal ocean waters: a joint retrieval algorithm for aerosol and water-leaving radiance properties
Meng Gao, Peng-Wang Zhai, Bryan A. Franz, Yongxiang Hu, Kirk Knobelspiesse, P. Jeremy Werdell, Amir Ibrahim, Brian Cairns, and Alison Chase
Atmos. Meas. Tech., 12, 3921-3941, https://doi.org/10.5194/amt-12-3921-2019, 2019

Ocean color remote sensing is a challenging task over coastal waters due to the complex optical properties of aerosols and hydrosols. In order to conduct accurate atmospheric correction, we previously implemented a joint retrieval algorithm, hereafter referred to as the Multi-Angular Polarimetric Ocean coLor (MAPOL) algorithm, to obtain the aerosol and water-leaving signal simultaneously. The MAPOL algorithm has been validated with synthetic data generated by a vector radiative transfer model, and good retrieval performance has been demonstrated in terms of both aerosol and ocean water optical properties (Gao et al., 2018). In this work we applied the algorithm to airborne polarimetric measurements from the Research Scanning Polarimeter (RSP) over both open and coastal ocean waters acquired in two field campaigns: the Ship-Aircraft Bio-Optical Research (SABOR) in 2014 and the North Atlantic Aerosols and Marine Ecosystems Study (NAAMES) in 2015 and 2016. Two different yet related bio-optical models are designed for ocean water properties. One model aligns with traditional open ocean water bio-optical models that parameterize the ocean optical properties in terms of the concentration of chlorophyll a. The other is a generalized bio-optical model for coastal waters that includes seven free parameters to describe the absorption and scattering by phytoplankton, colored dissolved organic matter, and nonalgal particles. The retrieval errors of both aerosol optical depth and the water-leaving radiance are evaluated. Through the comparisons with ocean color data products from both in situ measurements and the Moderate Resolution Imaging Spectroradiometer (MODIS), and the aerosol product from both the High Spectral Resolution Lidar (HSRL) and the Aerosol Robotic Network (AERONET), the MAPOL algorithm demonstrates both flexibility and accuracy in retrieving aerosol and water-leaving radiance properties under various aerosol and ocean water conditions.

Stability of Halocarbons in Whole Air Samples from the Upper Troposphere and Lowermost Stratosphere

Wed, 07/17/2019 - 18:00
Stability of Halocarbons in Whole Air Samples from the Upper Troposphere and Lowermost Stratosphere
Tanja J. Schuck, Ann-Katrin Blank, Elisa Rittmeier, Jonathan Williams, Carl A. M. Brenninkmeijer, Andreas Engel, and Andreas Zahn
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2019-259,2019
Manuscript under review for AMT (discussion: open, 1 comment)
Air sample collection aboard aircraft is a tool to measure atmospheric trace gas mixing ratios at altitude. We present results on the stability of 28 halocarbons during storage of air samples collected in stainless steel flasks inside an automated air sampling unit which is part of the CARIBIC instrument package. Selected fluorinated compounds grew during the experiments while short-lived compounds got depleted. Selected substances were additionally influenced by high mixing ratios of ozone.

Wind sensing with drone mounted wind lidars: proof of concept

Wed, 07/17/2019 - 18:00
Wind sensing with drone mounted wind lidars: proof of concept
Nikola Vasiljević, Michael Harris, Anders Tegtmeier Pedersen, Gunhild Rolighed Thorsen, Mark Pitter, Jane Harris, Kieran Bajpai, and Michael Courtney
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2019-102,2019
Manuscript under review for AMT (discussion: open, 0 comments)
In this paper we present the preliminary results of the proof of concept stage of a drone-based wind lidar system development. To test the POC drone-lidar system we hovered the drone next to mast-mounted sonic anemometers at the Risø test center. The preliminary results of the intercomparison between the measurements derived from the POC system and one of the sonic anemometers show good agreement.

Laboratory and field evaluation of the Aerosol Dynamics Inc. concentrator (ADIc) for aerosol mass spectrometry

Tue, 07/16/2019 - 18:00
Laboratory and field evaluation of the Aerosol Dynamics Inc. concentrator (ADIc) for aerosol mass spectrometry
Sanna Saarikoski, Leah R. Williams, Steven R. Spielman, Gregory S. Lewis, Arantzazu Eiguren-Fernandez, Minna Aurela, Susanne V. Hering, Kimmo Teinilä, Philip Croteau, John T. Jayne, Thorsten Hohaus, Douglas R. Worsnop, and Hilkka Timonen
Atmos. Meas. Tech., 12, 3907-3920, https://doi.org/10.5194/amt-12-3907-2019, 2019
An air-to-air ultrafine particle concentrator (Aerosol Dynamics Inc. concentrator; ADIc) has been tailored for the low (~ 0.08 L min−1) inlet flow of aerosol mass spectrometers, and it provides a factor of 8–21 enrichment in the concentration of particles. The ADIc was evaluated in laboratory and field measurements. The results showed that the concentration factor depends primarily on the ratio between the sample flow and the output flow and is independent of particle size above about 10 nm.

Cross-comparison of cloud liquid water path derived from observations by two space-borne and one ground-based instrument in Northern Europe

Tue, 07/16/2019 - 18:00
Cross-comparison of cloud liquid water path derived from observations by two space-borne and one ground-based instrument in Northern Europe
Vladimir S. Kostsov, Anke Kniffka, Martin Stengel, and Dmitry V. Ionov
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2019-225,2019
Manuscript under review for AMT (discussion: open, 0 comments)

Cloud liquid water path (LWP) is one of the target atmospheric parameters retrieved remotely from ground-based and space-borne platforms using different observation methods and processing algorithms. Validation of LWP retrievals is a complicated task since a cloud cover is characterised by strong temporal and spatial variability while remote sensing methods have different temporal and spatial resolution. An attempt has been made to compare and analyse the collocated LWP data delivered by two satellite instruments SEVIRI and AVHRR together with the data derived from microwave observations by the ground-based radiometer RPG‑HATPRO. The geographical region of interest is the vicinity of St.Petersburg, Russia, where the RPG‑HATPRO radiometer is operating. The study is focused on two problems. The first one is the so-called scale difference problem which originates from dissimilar spatial resolutions of measurements. The second problem refers to the land-sea LWP gradient. The radiometric site is located 2.5 km from the coastline where the effects of the LWP gradient are pronounced. A good agreement of data obtained at the microwave radiometer location by all three instruments (HATPRO, SEVIRI and AVHRR) during warm and cold seasons is demonstrated (the largest correlation coefficient 0.93 was detected for HATPRO and AVHRR data sets). The analysis showed no bias of the SEVIRI results with respect to HATPRO data and a high bias (0.013–0.017 kg m−2) of the AVHRR results for both warm and cold seasons. The analysis of LWP maps plotted on the basis of the SEVIRI and AVHRR measurements over land and water surfaces in the vicinity of St.Petersburg revealed the unexpectedly high LWP values delivered by AVHRR during cold season over the Neva river bay and over the Saimaa Lake and the abnormal land-sea LWP gradient in these areas. For the detailed evaluation of atmospheric state and ice cover in the considered geographical regions during the periods of ground-based and satellite measurements, reanalysis data were used. It is shown that the most probable reason for the observed artifacts in the AVHRR measurements over water/ice surfaces is the coarse resolution of the land-sea and snow/ice masks used by the AVHRR retrieval algorithm. The influence of a cloud field inhomogeneity on the agreement between the satellite and the ground-based data was studied. For this purpose, the simple estimate of the LWP temporal variability was used as a measure of the spatial inhomogeneity. It has been demonstrated that both instruments are equally sensitive to the inhomogeneity of a cloud field despite the fact that they have different spatial resolution.

Measurement of ammonia, amines and iodine species using protonated water cluster chemical ionization mass spectrometry

Tue, 07/16/2019 - 18:00
Measurement of ammonia, amines and iodine species using protonated water cluster chemical ionization mass spectrometry
Joschka Pfeifer, Mario Simon, Martin Heinritzi, Felix Piel, Lena Weitz, Dongyu Wang, Manuel Granzin, Tatjana Müller, Steffen Bräkling, Jasper Kirkby, Joachim Curtius, and Andreas Kürten
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2019-215,2019
Manuscript under review for AMT (discussion: open, 0 comments)
Ammonia is an important atmospheric trace gas that affects secondary aerosol formation and, together with sulfuric acid, the formation of new particles. A measurement technique is presented that uses high-resolution mass spectrometry and protonated water clusters for the ultra-sensitive detection of ammonia at single-digit pptv levels. The instrument is further capable of measuring amines and a suite of iodine species at sub-pptv levels.

An adaptation of the CO2 slicing technique for the Infrared Atmospheric Sounding Interferometer to obtain the height of tropospheric volcanic ash clouds

Mon, 07/15/2019 - 18:00
An adaptation of the CO2 slicing technique for the Infrared Atmospheric Sounding Interferometer to obtain the height of tropospheric volcanic ash clouds
Isabelle A. Taylor, Elisa Carboni, Lucy J. Ventress, Tamsin A. Mather, and Roy G. Grainger
Atmos. Meas. Tech., 12, 3853-3883, https://doi.org/10.5194/amt-12-3853-2019, 2019
Volcanic ash is a hazard associated with volcanoes. Knowing an ash cloud’s location is essential for minimising the hazard. This includes knowing the height. This study adapted a well-known technique for obtaining the height of meteorological clouds, known as CO2 slicing, for volcanic ash. Modelled data were used to refine the method and then demonstrate that the technique could work for volcanic ash. It was then successfully applied to data from the Eyjafjallajökull and Grímsvötn eruptions.

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

Mon, 07/15/2019 - 18:00
Classification of iron oxide aerosols by a single particle soot photometer using supervised machine learning
Kara D. Lamb
Atmos. Meas. Tech., 12, 3885-3906, https://doi.org/10.5194/amt-12-3885-2019, 2019
Recent atmospheric observations have indicated emissions of iron-oxide-containing aerosols from anthropogenic sources could be 8x 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.

A Convolutional Neural Network for Classifying Cloud Particles Recorded by Imaging Probes

Mon, 07/15/2019 - 18:00
A Convolutional Neural Network for Classifying Cloud Particles Recorded by Imaging Probes
Georgios Touloupas, Annika Lauber, Jan Henneberger, Alexander Beck, Thomas Hofmann, and Aurélien Lucchi
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2019-206,2019
Manuscript under review for AMT (discussion: open, 0 comments)
Images of cloud particles give important information to improve our understanding of microphysical cloud processes. For phase-resolved measurements, a large number of water droplets and ice crystals needs to be classified by an automated approach. In this study, a convolutional neural network was designed, which exceeds the classification ability of traditional methods and therefore shortens the analysis procedure of cloud particle images.

On the information content in linear horizontal delay gradients estimated from space geodesy observations

Fri, 07/12/2019 - 18:00
On the information content in linear horizontal delay gradients estimated from space geodesy observations
Gunnar Elgered, Tong Ning, Peter Forkman, and Rüdiger Haas
Atmos. Meas. Tech., 12, 3805-3823, https://doi.org/10.5194/amt-12-3805-2019, 2019
Within the EU COST Action ES1206 we have studied the horizontal variability of the atmosphere using signals from GPS satellites, distant quasars, and a microwave radiometer. We find a consistent picture: horizontal variability over timescales of months are mainly due to atmospheric pressure, whereas water vapour is the main cause of variations over times from minutes to hours. An understanding of these variations helps to improve the accuracy of GPS applications in both geodesy and meteorology.

Method to retrieve cloud condensation nuclei number concentrations using lidar measurements

Fri, 07/12/2019 - 18:00
Method to retrieve cloud condensation nuclei number concentrations using lidar measurements
Wangshu Tan, Gang Zhao, Yingli Yu, Chengcai Li, Jian Li, Ling Kang, Tong Zhu, and Chunsheng Zhao
Atmos. Meas. Tech., 12, 3825-3839, https://doi.org/10.5194/amt-12-3825-2019, 2019
A new method to retrieve CCN number concentrations using multiwavelength Raman lidars is proposed. The method implements hygroscopic enhancements of backscatter and extinction with relative humidity to represent particle hygroscopicity. The retrieved CCN number concentrations are in good agreement with theoretical calculated values. Sensitivity tests indicate that retrieval error in CCN arises mostly from uncertainties in extinction coefficients and RH profiles.

Separation and detection of aqueous atmospheric aerosol mimics using supercritical fluid chromatography–mass spectrometry

Fri, 07/12/2019 - 18:00
Separation and detection of aqueous atmospheric aerosol mimics using supercritical fluid chromatography–mass spectrometry
Daisy N. Grace, Melissa B. Sebold, and Melissa M. Galloway
Atmos. Meas. Tech., 12, 3841-3851, https://doi.org/10.5194/amt-12-3841-2019, 2019
The identification and quantification of compounds within an atmospheric particle can be difficult to achieve. We present a supercritical fluid chromatography method to separate these compounds prior to mass spectrometry analysis. The aqueous methylglyoxal–ammonium sulfate system was used as a proxy for atmospheric aerosol; polar columns combined with a carbon dioxide and methanol mobile phase provided the most efficient separation. This method can be extended to other atmospheric systems.

Performance Evaluation of THz Atmospheric Limb Sounder (TALIS) of China

Fri, 07/12/2019 - 18:00
Performance Evaluation of THz Atmospheric Limb Sounder (TALIS) of China
Wenyu Wang, Zhenzhan Wang, and Yongqiang Duan
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2019-212,2019
Manuscript under review for AMT (discussion: open, 1 comment)
THz Atmospheric Limb Sounder (TALIS) is a microwave limb sounder designed to measure the temperature and chemical species. The instrument will make an important contribution to monitoring the chemistry of the middle atmosphere. This paper describes the performance of this instrument. We use radiative transfer model to evaluate its performance. As a result, the retrieval precision is quite acceptable.

Estimation of liquid water path below the melting layer in stratiform precipitation systems using radar measurements during MC3E

Thu, 07/11/2019 - 18:00
Estimation of liquid water path below the melting layer in stratiform precipitation systems using radar measurements during MC3E
Jingjing Tian, Xiquan Dong, Baike Xi, Christopher R. Williams, and Peng Wu
Atmos. Meas. Tech., 12, 3743-3759, https://doi.org/10.5194/amt-12-3743-2019, 2019
Liquid water path (LWP) is a combination of rain liquid water path (RLWP) and cloud liquid water path (CLWP) in stratiform precipitation systems. LWP partitioning is important but poorly understood. Here we estimate the RLWP and CLWP below the melting base simultaneously and separately using ceilometer and radar measurements. Results show that the occurrence of cloud particles below the melting base is low; however, when cloud particles exist, the CLWP value is much larger than the RLWP.

Linearization of the effect of slit function changes for improving Ozone Monitoring Instrument ozone profile retrievals

Thu, 07/11/2019 - 18:00
Linearization of the effect of slit function changes for improving Ozone Monitoring Instrument ozone profile retrievals
Juseon Bak, Xiong Liu, Kang Sun, Kelly Chance, and Jae-Hwan Kim
Atmos. Meas. Tech., 12, 3777-3788, https://doi.org/10.5194/amt-12-3777-2019, 2019
This work improves OMI ozone profile retrievals by accounting for spectral fit residuals caused by slit function errors as a pseudo absorber in the optimal-estimation-based spectral fitting process.

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