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 4 hours ago

ELIFAN, an algorithm for the estimation of cloud cover from sky imagers

Mon, 10/21/2019 - 17:35
ELIFAN, an algorithm for the estimation of cloud cover from sky imagers
Marie Lothon, Paul Barnéoud, Omar Gabella, Fabienne Lohou, Solène Derrien, Sylvain Rondi, Marjolaine Chiriaco, Sophie Bastin, Jean-Charles Dupont, Martial Haeffelin, Jordi Badosa, Nicolas Pascal, and Nadège Montoux
Atmos. Meas. Tech., 12, 5519–5534, https://doi.org/10.5194/amt-12-5519-2019, 2019
In the context of an atmospheric network of instrumented sites equipped with sky cameras for cloud monitoring, we present an algorithm named ELIFAN, which aims to estimate the cloud cover amount from full-sky visible daytime images. ELIFAN is based on red-to-blue ratio thresholding applied on the image pixels and on the use of a blue-sky library. We present its principle and its performance and highlight the interest of combining several complementary instruments.

Evaluation of MOPITT Version 7 joint TIR–NIR XCO retrievals with TCCON

Mon, 10/21/2019 - 17:35
Evaluation of MOPITT Version 7 joint TIR–NIR XCO retrievals with TCCON
Jacob K. Hedelius, Tai-Long He, Dylan B. A. Jones, Bianca C. Baier, Rebecca R. Buchholz, Martine De Mazière, Nicholas M. Deutscher, Manvendra K. Dubey, Dietrich G. Feist, David W. T. Griffith, Frank Hase, Laura T. Iraci, Pascal Jeseck, Matthäus Kiel, Rigel Kivi, Cheng Liu, Isamu Morino, Justus Notholt, Young-Suk Oh, Hirofumi Ohyama, David F. Pollard, Markus Rettinger, Sébastien Roche, Coleen M. Roehl, Matthias Schneider, Kei Shiomi, Kimberly Strong, Ralf Sussmann, Colm Sweeney, Yao Té, Osamu Uchino, Voltaire A. Velazco, Wei Wang, Thorsten Warneke, Paul O. Wennberg, Helen M. Worden, and Debra Wunch
Atmos. Meas. Tech., 12, 5547–5572, https://doi.org/10.5194/amt-12-5547-2019, 2019
We seek ways to improve the accuracy of column measurements of carbon monoxide (CO) – an important tracer of pollution – made from the MOPITT satellite instrument. We devise a filtering scheme which reduces the scatter and also eliminates bias among the MOPITT detectors. Compared to ground-based observations, MOPITT measurements are about 6 %–8 % higher. When MOPITT data are implemented in a global assimilation model, they tend to reduce the model mismatch with aircraft measurements.

Molecular characterization of alkyl nitrates in atmospheric aerosols by ion mobility mass spectrometry

Mon, 10/21/2019 - 17:35
Molecular characterization of alkyl nitrates in atmospheric aerosols by ion mobility mass spectrometry
Xuan Zhang, Haofei Zhang, Wen Xu, Xiaokang Wu, Geoffrey S. Tyndall, John J. Orlando, John T. Jayne, Douglas R. Worsnop, and Manjula R. Canagaratna
Atmos. Meas. Tech., 12, 5535–5545, https://doi.org/10.5194/amt-12-5535-2019, 2019
We develop a new technique to characterize organic nitrates as intact molecules in atmospheric aerosols, and we apply this technique to identify hydroxy nitrates in secondary organic aerosols produced from the photochemical oxidation of isoprene.

Cloud Detection over Snow and Ice with Oxygen A- and B-band Observations from the Earth Polychromatic Imaging Camera (EPIC)

Mon, 10/21/2019 - 17:35
Cloud Detection over Snow and Ice with Oxygen A- and B-band Observations from the Earth Polychromatic Imaging Camera (EPIC)
Yaping Zhou, Yuekui Yang, Meng Gao, and Peng-Wang Zhai
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2019-345,2019
Manuscript under review for AMT (discussion: open, 0 comments)
Satellite cloud detection over snow and ice has been difficult for passive remote sensing instruments due to the lack of contrast between clouds and the bright and cold surfaces;The Earth Polychromatic Imaging Camera (EPIC) onboard the Deep Space Climate Observatory (DSCOVR) has very limited channels. This study investigates the methodology of applying EPIC’s two oxygen absorption band pair ratios for cloud detection over snow and ice surfaces.

Machine learning as an inversion algorithm for aerosol profile and property retrieval from multi-axis differential absorption spectroscopy measurements: a feasibility study

Mon, 10/21/2019 - 17:35
Machine learning as an inversion algorithm for aerosol profile and property retrieval from multi-axis differential absorption spectroscopy measurements: a feasibility study
Yun Dong, Elena Spinei, and Anuj Karpatne
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2019-368,2019
Manuscript under review for AMT (discussion: open, 0 comments)

In this study, we explore a new approach based on machine learning (ML) for deriving aerosol extinction coefficient profiles, single scattering albedo and asymmetry parameter at 360 nm from a single MAX-DOAS sky scan. Our method relies on a multi-output sequence-to-sequence model combining Convolutional Neural Networks (CNN) for feature extraction and Long Short-Term Memory networks (LSTM) for profile prediction. The model was trained and evaluated using data simulated by VLIDORT v2.7, which contains 1 459 200 unique mappings. 75 % randomly selected simulations were used for training and the remaining 25 % for validation. The overall error of estimated aerosol properties for (1) total AOD is −1.4 ± 10.1 %, (2) for single scattering albedo is 0.1 ± 3.6 %; and (3) asymmetry factor is −0.1 ± 2.1 %. The resulting model is capable of retrieving aerosol extinction coefficient profiles with degrading accuracy as a function of height. The uncertainty due to the randomness in ML training is also discussed.

Synergistic radar and radiometer retrievals of ice hydrometeors

Mon, 10/21/2019 - 17:35
Synergistic radar and radiometer retrievals of ice hydrometeors
Simon Pfreundschuh, Patrick Eriksson, Stefan A. Buehler, Manfred Brath, David Duncan, Richard Larsson, and Robin Ekelund
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2019-369,2019
Manuscript under review for AMT (discussion: open, 0 comments)
The next generation of European operational weather satellites will carry a novel microwave sensor, the Ice Cloud Imager (ICI), which will provide observations of clouds at microwave frequencies that were not available before. We investigate the potential benefits of combining observations from ICI with that of a radar. We find that such combined observations provide additional information on the properties of the cloud and help to reduce uncertainties in retrieved mass and number densities.

Sulfur dioxide layer height retrieval from Sentinel-5 Precursor/TROPOMI using FP_ILM

Fri, 10/18/2019 - 17:35
Sulfur dioxide layer height retrieval from Sentinel-5 Precursor/TROPOMI using FP_ILM
Pascal Hedelt, Dmitry S. Efremenko, Diego G. Loyola, Robert Spurr, and Lieven Clarisse
Atmos. Meas. Tech., 12, 5503–5517, https://doi.org/10.5194/amt-12-5503-2019, 2019
Sulfur dioxide (SO2) emitted during volcanic eruptions poses not only a major threat to local populations, air quality, and aviation but also has an impact on the climate. The satellite-based detection of the SO2 plume is easy; however, it requires exact knowledge of the SO2 layer height. This paper presents a new method for the extremely fast and accurate determination of the layer height, which is essential in volcanic plume forecasts and the exact determination of the SO2 density.

Comparison of GTO-ECV and Adjusted-MERRA total ozone columns from the last two decades and assessment of interannual variability

Fri, 10/18/2019 - 17:35
Comparison of GTO-ECV and Adjusted-MERRA total ozone columns from the last two decades and assessment of interannual variability
Melanie Coldewey-Egbers, Diego Loyola, Gordon Labow, and Stacey Frith
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2019-297,2019
Manuscript under review for AMT (discussion: open, 0 comments)
We compare total ozone columns from the satellite-based GOME-type Total Ozone Essential Climate Variable record and the Modern Era Retrospective Analysis for Research and Applications version 2 reanalysis during their overlap period from 1995 to 2018. Ozone columns and anomalies show a very good agreement in terms of spatial and temporal patterns. In the tropics the interannual variability is assessed by means of an EOF analysis and both data records show a remarkable consistency.

Changes in PM2.5 peat combustion source profiles with atmospheric aging in an oxidation flow reactor

Thu, 10/17/2019 - 17:35
Changes in PM2.5 peat combustion source profiles with atmospheric aging in an oxidation flow reactor
Judith C. Chow, Junji Cao, L.-W. Antony Chen, Xiaoliang Wang, Qiyuan Wang, Jie Tian, Steven Sai Hang Ho, Adam C. Watts, Tessa B. Carlson, Steven D. Kohl, and John G. Watson
Atmos. Meas. Tech., 12, 5475–5501, https://doi.org/10.5194/amt-12-5475-2019, 2019
Source profiles that allow peat fire contributions to be distinguished from other source contributions using receptor models are lacking for a wide variety of peat fuels and burning conditions. These profiles change with photochemical aging during transport. Fresh and aged profiles for a variety of peat fuels are measured with an oxidation flow reactor to improve source attributions at distant receptors.

Tracking down global NH3 point sources with wind-adjusted superresolution

Thu, 10/17/2019 - 17:35
Tracking down global NH3 point sources with wind-adjusted superresolution
Lieven Clarisse, Martin Van Damme, Cathy Clerbaux, and Pierre-François Coheur
Atmos. Meas. Tech., 12, 5457–5473, https://doi.org/10.5194/amt-12-5457-2019, 2019
An imaging technique called superresolution is applied to IASI satellite measurements of atmospheric ammonia (NH3). Taking into account wind fields, this technique reveals NH3 emission sources much better than previously possible. We present a new global NH3 point-source catalog consisting of more than 500 localized and categorized point sources related to agriculture and five different types of industry.

Ground-based Observations of Cloud and Drizzle Liquid Water Path in Stratocumulus Clouds

Thu, 10/17/2019 - 17:35
Ground-based Observations of Cloud and Drizzle Liquid Water Path in Stratocumulus Clouds
Maria P. Cadeddu, Virendra P. Ghate, and Mario Mech
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2019-346,2019
Manuscript under review for AMT (discussion: open, 0 comments)
A combination of ground-based active and passive sensors is used to partition cloud and precipitation liquid water path in open cell and closed cell stratocumuli. Results show that in the closed cell systems only ~20% of the available drizzle in the cloud falls below the cloud base, compared to ~40% in the open cell systems. The results also show that neglecting scattering effects when using microwave frequencies at and above 90 GHz leads to overestimation of the total liquid water path.

Early results and Validation of SAGE III-ISS Ozone Profile Measurements from Onboard the International Space Station

Wed, 10/16/2019 - 17:35
Early results and Validation of SAGE III-ISS Ozone Profile Measurements from Onboard the International Space Station
Michael P. McCormick, Liqiao Lei, and Michael T. Hill
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2019-353,2019
Manuscript under review for AMT (discussion: open, 0 comments)

The Stratospheric Aerosol and Gas Experiment III (SAGE III) instrument, was launched on February 19, 2017 from the NASA Kennedy Space Center, and integrated aboard the International Space Station (ISS). SAGE III-ISS has been providing ozone profile measurements since June, 2017. This paper presents an early validation of the Level 2 solar and lunar occultation ozone data products using ground-based lidar and ozonesondes from Hohenpeissenberg and Lauder, and satellite ozone vertical products from the Atmospheric Chemistry Experiment Fourier-Transform Spectrometer (ACE-FTS) instrument. The Hohenpeissenberg one-year lidar results show that the average difference of ozone concentration measured by SAGE III-ISS is less than 10 % between 15 and 45 km and less than 5 % between 20 and 40 km. Hohenpeissenberg ozonesonde comparisons are mostly within 10 % between 15 and 30 km. The Lauder lidar comparison results were less than 10 % between 17 and 40 km, and less than 10 % between 10 km and 30 km for Lauder ozonesondes. The seasonal average difference of ozone concentration between SAGE III-ISS and ACE-FTS was mostly less than 5 % between 20 and 45 km for both the northern and southern hemispheres. All results from these comparisons show that the SAGE III-ISS ozone solar data have exceptional accuracy between 20 and 30 km, and believable accuracy throughout the stratosphere. With few comparisons available, the percentage difference between the SAGE III-ISS lunar ozone data and the ozonesonde data is less than 10 % between 20 and 30 km. The percentage difference between the SAGE III-ISS lunar ozone data and the ACE-FTS ozone data is less than 10 % between 20 and 40 km.

Multifactor colorimetric analysis on pH-indicator papers: an optimized approach for direct determination of ambient aerosol pH

Wed, 10/16/2019 - 17:35
Multifactor colorimetric analysis on pH-indicator papers: an optimized approach for direct determination of ambient aerosol pH
Guo Li, Hang Su, Nan Ma, Guangjie Zheng, Uwe Kuhn, Meng Li, Thomas Klimach, Ulrich Pöschl, and Yafang Cheng
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2019-394,2019
Manuscript under review for AMT (discussion: open, 0 comments)
Aerosol acidity plays an important role in regulating the chemistry, health and ecological effect of aerosol particles. However, a direct measurement of aerosol pH is very challenging because of its fast transition and equilibrium with adjacent environments. Therefore, most early studies have to use modeled pH, resulting in intensive debates about model uncertainties. Here we developed an optimized approach to measure aerosol pH by using pH indicator papers combined with RGB-based colorimetry.

Improving the TROPOMI CO data product: update of the spectroscopic database and destriping of single orbits

Tue, 10/15/2019 - 17:35
Improving the TROPOMI CO data product: update of the spectroscopic database and destriping of single orbits
Tobias Borsdorff, Joost aan de Brugh, Andreas Schneider, Alba Lorente, Manfred Birk, Georg Wagner, Rigel Kivi, Frank Hase, Dietrich G. Feist, Ralf Sussmann, Markus Rettinger, Debra Wunch, Thorsten Warneke, and Jochen Landgraf
Atmos. Meas. Tech., 12, 5443–5455, https://doi.org/10.5194/amt-12-5443-2019, 2019
The study presents possible improvements of the TROPOMI CO dataset, which is a primary product of ESA's Sentinel-5P mission. We discuss the use of different molecular spectroscopic databases in the CO retrieval, the induced biases between TROPOMI CO and TCCON validation measurements, and the latitudinally dependent bias between TROPOMI CO and the CAMS-IFS model. Additionally, two methods for the stripe correction of single TROPOMI CO orbits are presented.

Airborne measurement of peroxy radicals using chemical amplification coupled with cavity ring down spectroscopy: the PeRCEAS instrument

Mon, 10/14/2019 - 17:35
Airborne measurement of peroxy radicals using chemical amplification coupled with cavity ring down spectroscopy: the PeRCEAS instrument
Midhun George, Maria Dolores Andrés Hernández, Vladyslav Nenakhov, Yangzhuoran Liu, and John Philip Burrows
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2019-359,2019
Manuscript under review for AMT (discussion: open, 0 comments)
The accurate measurement of peroxy radicals is essential for understanding the chemistry of air masses probed in the free troposphere. The PeRCEAS instrument has been designed, developed and thoroughly characterised for the measurement of the total sum of peroxy radicals (RO2*) on board of airborne platforms. Parameters expected to affect the precision and accuracy of the measurement have been investigated in detail.

Microwave and submillimeter wave scattering of oriented ice particles

Mon, 10/14/2019 - 17:35
Microwave and submillimeter wave scattering of oriented ice particles
Manfred Brath, Robin Ekelund, Patrick Eriksson, Oliver Lemke, and Stefan A. Buehler
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2019-382,2019
Manuscript under review for AMT (discussion: open, 0 comments)
Microwave dual-polarization observations consistently show that larger atmospheric ice particles tend to have a preferred orientation. Detailed simulations, recreating the observed polarization patterns, are presented in this study. We provide a publicly available database of microwave and submillimeter wave scattering properties of oriented ice particles.

In situ measurement of CO2 and CH4 from aircraft over northeast China and comparison with OCO-2 data

Mon, 10/14/2019 - 17:35
In situ measurement of CO2 and CH4 from aircraft over northeast China and comparison with OCO-2 data
Xiaoyu Sun, Minzheng Duan, Yang Gao, Rui Han, Denghui Ji, Wenxing Zhang, Nong Chen, Xiangao Xia, Hailei Liu, and Yanfeng Huo
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2019-363,2019
Manuscript under review for AMT (discussion: open, 0 comments)
The accurate measurement of greenhouse gases and its vertical distribution in the atmosphere is significant to the study of climate change and satellite remote sensing. The profiles of carbon dioxide and methane between 0.6∼7 km was measured by aircraft King Air 350ER in Jiansanjiang, Northeast China, on August 7–11, 2018. The profiles show strong variation with the altitude and time, so the vertical structure of gases should be taken into account in the current satellite retrieval algorithm.

Evaluation of satellite-based aerosol datasets and the CAMS reanalysis over ocean utilizing shipborne reference observations

Mon, 10/14/2019 - 17:35
Evaluation of satellite-based aerosol datasets and the CAMS reanalysis over ocean utilizing shipborne reference observations
Jonas Witthuhn, Anja Hünerbein, and Hartwig Deneke
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2019-321,2019
Manuscript under review for AMT (discussion: open, 0 comments)
Reliable reference measurements over ocean are essential for the evaluation and improvement of satellite- and model-based aerosol datasets. Here, a uniqe set of shipborne reference aerosol products obtained from Microtops sunphotometer and GUVis-3511 shadowband radiometer observations are compared to aerosol products from the MODIS and SEVIRI satellite sensors, and the CAMS reanalysis over the Atlantic ocean. The present evaluation highlights the importance of an aerosol-type based analysis.

Validating TROPOMI aerosol layer height retrievals with CALIOP data

Mon, 10/14/2019 - 17:35
Validating TROPOMI aerosol layer height retrievals with CALIOP data
Swadhin Nanda, Martin de Graaf, J. Pepijn Veefkind, Maarten Sneep, Mark ter Linden, Jiyunting Sun, and Pieternel F. Levelt
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2019-348,2019
Manuscript under review for AMT (discussion: open, 0 comments)
This paper discusses the validation of the TROPOspheric Monitoring Instrument (TROPOMI) aerosol layer height product, which is an estimate of the height of an aerosol layer using a spectrometer on board ESA's Sentinel-5 Precursor satellite mission. This study looks at a collection of colocations between TROPOMI and satellite instrument Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) on board NASA's Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) mission.

Estimating and Reporting Uncertainties in Remotely Sensed Atmospheric Composition and Temperature

Mon, 10/14/2019 - 17:35
Estimating and Reporting Uncertainties in Remotely Sensed Atmospheric Composition and Temperature
Thomas von Clarmann, Douglas A. Degenstein, Nathaniel J. Livesey, Stefan Bender, Amy Braverman, André Butz, Steven Compernolle, Robert Damadeo, Seth Dueck, Patrick Eriksson, Bernd Funke, Margaret C. Johnson, Yasuko Kasai, Arno Keppens, Anne Kleinert, Natalya A. Kramarova, Alexandra Laeng, Vivienne H. Payne, Alexei Rozanov, Tomohiro O. Sato, Matthias Schneider, Patrick Sheese, Viktoria Sofieva, Gabriele P. Stiller, Christian von Savigny, and Daniel Zawada
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2019-350,2019
Manuscript under review for AMT (discussion: open, 0 comments)
Remote sensing of atmospheric state variables typically relies on the inverse solution of the radiative transfer equation. An adequately characterized retrieval provides information on the uncertainties of the estimated state variables as well as on how any constraint or a priori assumption affects the estimate. This paper summarizes related techniques and provides recommendations for unified error reporting.

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