Nano-hygroscopicity tandem differential mobility analyzer (nano-HTDMA) for investigating hygroscopic properties of sub-10 nm aerosol nanoparticles
Ting Lei, Nan Ma, Juan Hong, Thomas Tuch, Xin Wang, Zhibin Wang, Mira Pöhlker, Maofa Ge, Weigang Wang, Eugene Mikhailov, Thorsten Hoffmann, Ulrich Pöschl, Hang Su, Alfred Wiedensohler, and Yafang Cheng
Atmos. Meas. Tech. Discuss., https//doi.org/10.5194/amt-2020-110,2020
Preprint under review for AMT (discussion: open, 0 comments)
We present a newly designed and self-assembled nano-hygroscopicity tandem differential mobility analyzer (nano-HTDMA) apparatus that enables high accuracy and precision in hygroscopic growth measurements of aerosol nanoparticles with diameters less than 10 nm. We further introduce the comprehensive methods for system calibration and performance of the system.
Intercomparison and Evaluation of Ground- and Satellite-Based Stratospheric Ozone and Temperature profiles above Observatoire Haute Provence during the Lidar Validation NDACC Experiment (LAVANDE)
Robin Wing, Wolfgang Steinbrecht, Sophie Godin-Beekmann, Thomas J. McGee, John T. Sullivan, Grant Sumnicht, Gerard Ancellet, Alain Hauchecorne, Sergey Khaykin, and Philippe Keckhut
Atmos. Meas. Tech. Discuss., https//doi.org/10.5194/amt-2020-9,2020
Preprint under review for AMT (discussion: open, 0 comments)
A lidar intercomparison campaign was conducted over a period of 28 nights at L'Observatoire de Haute Provence (OHP) in 2017 and 2018. The objective is to validate the ozone and temperature profiles at OHP to ensure the quality of the data submitted to the NDACC database remains high. A mobile reference lidar operated by NASA was transported to OHP and operated concurrently with the French lidars. Agreement for ozone was better than 5 % between 20 and 40 km and temperatures were equal within 3 K.
On the retrieval of snow grain morphology, the accuracy of simulated reflectance over snow using airborne measurements in the Arctic
Soheila Jafariserajehlou, Vladimir V. Rozanov, Marco Vountas, Charles K. Gatebe, and John P. Burrows
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2020-58,2020
Preprint under review for AMT (discussion: open, 1 comment)
In this work, we study the retrieval of snow grain morphologies and their impact on the reflectance in a coupled snow-atmosphere system. We present a sensitivity study to highlight the importance of having adequate information about snow and atmosphere. A novel two-stage algorithm to retrieve the size and shape of snow grains is presented. The reflectance simulation results are compared with that of airborne measurements; the high correlation of 0.98 at IR and 0.88–98 at VIS channel is achieved.
An Examination of Enhanced Atmospheric Methane Detection Methods for Predicting Performance of a Novel Multiband Uncooled Radiometer Imager
Cody M. Webber and John P. Kerekes
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2020-53,2020
Preprint under review for AMT (discussion: open, 0 comments)
Here we present a study performed to determine the methane detection capabilities of a novel remote thermal instrument, the Multiband Uncooled Radiometer Imager. We utilize a novel methane detection approach, the normalized differential methane index, that when applied to simulated multispectral thermal imagery with a single spectral channel dedicated to methane detection shows similar results to a state of the art method, the matched filter approach.
On the retrieval of snow grain morphology, the accuracy of simulated reflectance over snow using airborne measurements in the Arctic
Soheila Jafariserajehlou, Vladimir V. Rozanov, Marco Vountas, Charles K. Gatebe, and John P. Burrows
Atmos. Meas. Tech. Discuss., https//doi.org/10.5194/amt-2020-58,2020
Preprint under review for AMT (discussion: open, 1 comment)
In this work, we study the retrieval of snow grain morphologies and their impact on the reflectance in a coupled snow-atmosphere system. We present a sensitivity study to highlight the importance of having adequate information about snow and atmosphere. A novel two-stage algorithm to retrieve the size and shape of snow grains is presented. The reflectance simulation results are compared with that of airborne measurements; the high correlation of 0.98 at IR and 0.88–98 at VIS channel is achieved.
An Examination of Enhanced Atmospheric Methane Detection Methods for Predicting Performance of a Novel Multiband Uncooled Radiometer Imager
Cody M. Webber and John P. Kerekes
Atmos. Meas. Tech. Discuss., https//doi.org/10.5194/amt-2020-53,2020
Preprint under review for AMT (discussion: open, 0 comments)
Here we present a study performed to determine the methane detection capabilities of a novel remote thermal instrument, the Multiband Uncooled Radiometer Imager. We utilize a novel methane detection approach, the normalized differential methane index, that when applied to simulated multispectral thermal imagery with a single spectral channel dedicated to methane detection shows similar results to a state of the art method, the matched filter approach.
By Kathy Bogan, CIRES
Liquid meltwater can sometimes flow deep below the Greenland Ice Sheet in winter, not just in the summer, according to work published in the AGU journal Geophysical Research Letters today. That finding means that scientists seeking to understand sea-level rise and the future of the Greenland Ice Sheet need to collect data during the dark Arctic winter with scant hours of daylight and temperatures that dip below -30 degrees Celsius (-22 degrees Fahrenheit).
“This observation raises questions for the Greenland research community, and motivates the need for future work on wintertime hydrology in Greenland,” said lead author Lincoln Pitcher, a Visiting Fellow at CIRES, part of the University of Colorado Boulder. Pitcher began this work while he was a graduate student at the University of California Los Angeles, and his co-authors are from seven different states and Denmark.
The Isortoq River draining from the terminus of Isunguata Sermia outlet glacier in southwest Greenland in July 2014. Flowing water was discovered in this river the following winter while the river was frozen over and temperatures were below freezing. Credit: CIRES
When evidence suggested that some of Greenland’s glaciers were storing meltwater through the winter, Pitcher set out for southwest Greenland to see if any of this meltwater was also leaving the ice sheet during winter. In February 2015, he and his colleague Colin Gleason of the University of Massachusetts Amherst dragged a ground-penetrating radar across frozen rivers downstream of the edge of the ice sheet and drilled boreholes to see if any water was leaving the ice sheet and flowing beneath river ice. They surveyed rivers draining five Greenland Ice Sheet outlet glaciers, and discovered meltwater flowing at just one site, the Isortoq River. In summertime, the Isotoq drains meltwater from the terminus of the Isunguata Sermia outlet glacier. In winter, the river appears frozen, but Pitcher and Gleason found slowly flowing liquid water there.
It was “a trickle, not a torrent,” Pitcher said, and the water was flowing below half a meter of ice while temperatures were well below zero. Pitcher and Gleason collected water samples and geochemical analysis indicated that it had come from under the ice sheet itself.
The team concluded that it is possible the bed of the Greenland Ice Sheet can stay wet and drain small amounts of water year-round. This finding is important for understanding how meltwater from the ice surface moves through the ice sheet, is retained, refreezes and/or ultimately drains into rivers and/or the global ocean.
It is often assumed that Greenland’s drainage system lies dormant during winter. Pitcher’s team’s findings highlight a growing need for year-round Arctic hydrologic investigations, not just in summer.
Kathy Bogan is a graphic designer at CIRES. This post was originally published on the CIRES website.
The post Greenland Ice Sheet meltwater can flow in winter, too appeared first on GeoSpace.
Characterization of a Non-Thermal Plasma Source for the Use as a Mass Spec Calibration Tool and Non-Radioactive Aerosol Charger
Christian Tauber, David Schmoll, Johannes Gruenwald, Sophia Brilke, Peter Josef Wlasits, Paul Martin Winkler, and Daniela Wimmer
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2020-54,2020
Preprint under review for AMT (discussion: open, 0 comments)
In this paper we show that a commercially available plasma charger with nitrogen as working gas can enhance the charging probability for sub-10 nm particles. In addition, the charger ion mobilities and the chemical composition have been examined using an atmospheric pressure interface – time-of-flight mass spectrometer (APi-TOF MS) and comparison of the experimental results revealed that the generated neutralizer ions are not dependent on the charging mechanism.
Characterization of a Non-Thermal Plasma Source for the Use as a Mass Spec Calibration Tool and Non-Radioactive Aerosol Charger
Christian Tauber, David Schmoll, Johannes Gruenwald, Sophia Brilke, Peter Josef Wlasits, Paul Martin Winkler, and Daniela Wimmer
Atmos. Meas. Tech. Discuss., https//doi.org/10.5194/amt-2020-54,2020
Preprint under review for AMT (discussion: open, 0 comments)
In this paper we show that a commercially available plasma charger with nitrogen as working gas can enhance the charging probability for sub-10 nm particles. In addition, the charger ion mobilities and the chemical composition have been examined using an atmospheric pressure interface – time-of-flight mass spectrometer (APi-TOF MS) and comparison of the experimental results revealed that the generated neutralizer ions are not dependent on the charging mechanism.
Estimating raindrop size distributions using microwave link measurements: potential and limitations
Thomas C. van Leth, Hidde Leijnse, Aart Overeem, and Remko Uijlenhoet
Atmos. Meas. Tech., 13, 1797–1815, https://doi.org/10.5194/amt-13-1797-2020, 2020
We present a method of using collocated microwave link instruments to estimate the average size distribution of raindrops along a path of several kilometers. Our method is validated using simulated fields as well as five laser disdrometers installed along a path. We also present preliminary results from an experimental setup measuring at 26 and 38 GHz along a 2.2 km path. We show that a retrieval on the basis of microwave links can be highly accurate, provided the base power level is stable.
Effect of OH emission on the temperature and wind measurements derived from limb-viewing observations of the 1.27 µm O2 dayglow
Kuijun Wu, Weiwei He, Yutao Feng, Yuanhui Xiong, and Faquan Li
Atmos. Meas. Tech., 13, 1817–1824, https://doi.org/10.5194/amt-13-1817-2020, 2020
The 1.27 μm O2 dayglow is well-suited for remote sensing in near-space. The main goal of this paper is to discuss the effect of OH radiance on the wind and temperature measurements derived from limb-viewing observations of the O2 dayglow. It is apparent from the simulations that the presence of OH radiance as an interfering species decreases the wind and temperature accuracy at all altitudes, but this effect can be reduced considerably by improving OH radiance knowledge.
Spatiotemporal variability of solar radiation introduced by clouds over Arctic sea ice
Carola Barrientos Velasco, Hartwig Deneke, Hannes Griesche, Patric Seifert, Ronny Engelmann, and Andreas Macke
Atmos. Meas. Tech., 13, 1757–1775, https://doi.org/10.5194/amt-13-1757-2020, 2020
In the changing Arctic, quantifying the resulting variability of incoming solar radiation is important to better elucidate the net radiative effect of clouds. As part of a multidisciplinary expedition in the central Arctic held in early summer 2017, a novel network of pyranometers was deployed over an ice floe to investigate the spatiotemporal variability of solar radiation under different sky conditions. This study presents the collected data and an analysis of the spatiotemporal variability.
A multi-axis differential optical absorption spectroscopy aerosol profile retrieval algorithm for high-altitude measurements: application to measurements at Schneefernerhaus (UFS), Germany
Zhuoru Wang, Ka Lok Chan, Klaus-Peter Heue, Adrian Doicu, Thomas Wagner, Robert Holla, and Matthias Wiegner
Atmos. Meas. Tech., 13, 1835–1866, https://doi.org/10.5194/amt-13-1835-2020, 2020
We present a new aerosol profile retrieval algorithm for MAX-DOAS measurements at high-altitude sites and applied to the MAX-DOAS measurements at UFS. The retrieval algorithm is based on a O4 DSCD lookup table which is dedicated to high-altitude MAX-DOAS measurements. The comparison of retrieved aerosol optical depths (AODs) to sun photometer observations shows good agreement with a correlation coefficient (R) of 0.733 and 0.798 at 360 and 477 nm, respectively.
Comparison of optimal estimation HDO∕H2O retrievals from AIRS with ORACLES measurements
Robert L. Herman, John Worden, David Noone, Dean Henze, Kevin Bowman, Karen Cady-Pereira, Vivienne H. Payne, Susan S. Kulawik, and Dejian Fu
Atmos. Meas. Tech., 13, 1825–1834, https://doi.org/10.5194/amt-13-1825-2020, 2020
This study is the first assessment and validation of AIRS HDO / H2O retrieved by optimal estimation. Initial comparisons with in situ measurements from NASA ORACLES are promising: the small bias and consistent rms of AIRS suggest that AIRS has well-characterized HDO / H2O. This analysis opens the possibility of a new 17-year long-term data record of global tropospheric HDO / H2O measured from space.
Spatial distribution of cloud droplet size properties from Airborne Hyper-Angular Rainbow Polarimeter (AirHARP) measurements
Brent A. McBride, J. Vanderlei Martins, Henrique M. J. Barbosa, William Birmingham, and Lorraine A. Remer
Atmos. Meas. Tech., 13, 1777–1796, https://doi.org/10.5194/amt-13-1777-2020, 2020
Clouds play a large role in the way our Earth system distributes energy. The measurement of cloud droplet size distribution (DSD) is one way to connect small-scale cloud processes to scattered radiation. Our small satellite instrument, the Airborne Hyper-Angular Rainbow Polarimeter, is the first to infer DSDs over a wide spatial cloud field using polarized light. This study improves the way we interpret cloud properties and shows that high-quality science does not require a large taxpayer cost.
Estimating raindrop size distributions using microwave link measurements: potential and limitations
Thomas C. van Leth, Hidde Leijnse, Aart Overeem, and Remko Uijlenhoet
Atmos. Meas. Tech., 13, 1797–1815, https://doi.org/10.5194/amt-13-1797-2020, 2020
We present a method of using collocated microwave link instruments to estimate the average size distribution of raindrops along a path of several kilometers. Our method is validated using simulated fields as well as five laser disdrometers installed along a path. We also present preliminary results from an experimental setup measuring at 26 and 38 GHz along a 2.2 km path. We show that a retrieval on the basis of microwave links can be highly accurate, provided the base power level is stable.
Effect of OH emission on the temperature and wind measurements derived from limb-viewing observations of the 1.27 µm O2 dayglow
Kuijun Wu, Weiwei He, Yutao Feng, Yuanhui Xiong, and Faquan Li
Atmos. Meas. Tech., 13, 1817–1824, https://doi.org/10.5194/amt-13-1817-2020, 2020
The 1.27 μm O2 dayglow is well-suited for remote sensing in near-space. The main goal of this paper is to discuss the effect of OH radiance on the wind and temperature measurements derived from limb-viewing observations of the O2 dayglow. It is apparent from the simulations that the presence of OH radiance as an interfering species decreases the wind and temperature accuracy at all altitudes, but this effect can be reduced considerably by improving OH radiance knowledge.
Spatiotemporal variability of solar radiation introduced by clouds over Arctic sea ice
Carola Barrientos Velasco, Hartwig Deneke, Hannes Griesche, Patric Seifert, Ronny Engelmann, and Andreas Macke
Atmos. Meas. Tech., 13, 1757–1775, https://doi.org/10.5194/amt-13-1757-2020, 2020
In the changing Arctic, quantifying the resulting variability of incoming solar radiation is important to better elucidate the net radiative effect of clouds. As part of a multidisciplinary expedition in the central Arctic held in early summer 2017, a novel network of pyranometers was deployed over an ice floe to investigate the spatiotemporal variability of solar radiation under different sky conditions. This study presents the collected data and an analysis of the spatiotemporal variability.
A multi-axis differential optical absorption spectroscopy aerosol profile retrieval algorithm for high-altitude measurements: application to measurements at Schneefernerhaus (UFS), Germany
Zhuoru Wang, Ka Lok Chan, Klaus-Peter Heue, Adrian Doicu, Thomas Wagner, Robert Holla, and Matthias Wiegner
Atmos. Meas. Tech., 13, 1835–1866, https://doi.org/10.5194/amt-13-1835-2020, 2020
We present a new aerosol profile retrieval algorithm for MAX-DOAS measurements at high-altitude sites and applied to the MAX-DOAS measurements at UFS. The retrieval algorithm is based on a O4 DSCD lookup table which is dedicated to high-altitude MAX-DOAS measurements. The comparison of retrieved aerosol optical depths (AODs) to sun photometer observations shows good agreement with a correlation coefficient (R) of 0.733 and 0.798 at 360 and 477 nm, respectively.
Comparison of optimal estimation HDO∕H2O retrievals from AIRS with ORACLES measurements
Robert L. Herman, John Worden, David Noone, Dean Henze, Kevin Bowman, Karen Cady-Pereira, Vivienne H. Payne, Susan S. Kulawik, and Dejian Fu
Atmos. Meas. Tech., 13, 1825–1834, https://doi.org/10.5194/amt-13-1825-2020, 2020
This study is the first assessment and validation of AIRS HDO / H2O retrieved by optimal estimation. Initial comparisons with in situ measurements from NASA ORACLES are promising: the small bias and consistent rms of AIRS suggest that AIRS has well-characterized HDO / H2O. This analysis opens the possibility of a new 17-year long-term data record of global tropospheric HDO / H2O measured from space.
