Validation of XCO2 and XCH4 retrieved from a portable Fourier transform spectrometer with those from in-situ profiles from aircraft borne instruments
Hirofumi Ohyama, Isamu Morino, Voltaire A. Velazco, Theresa Klausner, Gerry Bagtasa, Matthäus Kiel, Matthias Frey, Akihiro Hori, Osamu Uchino, Tsuneo Matsunaga, Nicholas Deutscher, Joshua P. DiGangi, Yonghoon Choi, Glenn S. Diskin, Sally E. Pusede, Alina Fiehn, Anke Roiger, Michael Lichtenstern, Hans Schlager, Pao K. Wang, Charles C.-K. Cho, Maria Dolores Andrés-Hernández, and John P. Burrows
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2020-170,2020
Preprint under review for AMT (discussion: open, 0 comments)
Column-averaged dry-air mole fractions of CO2 and CH4 measured by a solar viewing portable Fourier transform spectrometer (EM27/SUN) were validated with in-situ profile data obtained during the transfer flights of two aircraft campaigns. Atmospheric dynamical properties based on ERA5 and WRF-Chem were used as criteria for selecting the best aircraft profiles for the validation. The resulting air mass independent correction factors for the EM27/SUN data were 0.9878 for CO2 and 0.9833 for CH4.
Evaluation of single-footprint AIRS CH4 Profile Retrieval Uncertainties Using Aircraft Profile Measurements
Susan S. Kulawik, John R. Worden, Vivienne H. Payne, Dejian Fu, Steve C. Wofsy, Kathryn McKain, Colm Sweeney, Bruce C. Daube Jr., Alan Lipton, Igor Polonsky, Yuguang He, Karen E. Cady-Pereira, Edward J. Dlugokencky, Daniel J. Jacob, and Yi Yin
Atmos. Meas. Tech. Discuss., https//doi.org/10.5194/amt-2020-145,2020
Preprint under review for AMT (discussion: open, 0 comments)
This paper shows comparisons of a new methane product from the AIRS satellite to aircraft-based observations. We show that this AIRS methane product provides useful information to study seasonal and global methane trends of this important greenhouse gas.
Mapping ice formation to mineral-surface topography using a micro mixing chamber with video and atomic-force microscopy
Raymond W. Friddle and Konrad Thürmer
Atmos. Meas. Tech., 13, 2209–2218, https://doi.org/10.5194/amt-13-2209-2020, 2020
An obstacle to predicting ice content in mixed-phase clouds is the inability to directly view atmospheric ice nucleation at the nanoscale, where this process occurs. Here we show how a cloud-like environment can be created in a small atomic-force microscopy (AFM) sample cell. By colocating video microscopy of ice formation with high-resolution AFM images, we quantitatively show how the surface topography, down to nanometer-length scales, can determine the preferential locations of ice formation.
Improved chloride quantification in quadrupole aerosol chemical speciation monitors (Q-ACSMs)
Anna K. Tobler, Alicja Skiba, Dongyu S. Wang, Philip Croteau, Katarzyna Styszko, Jarosław Nęcki, Urs Baltensperger, Jay G. Slowik, and André S. H. Prévôt
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2020-117,2020
Preprint under review for AMT (discussion: open, 0 comments)
Some quadrupole aerosol chemical speciation monitors (Q-ACSMs) have shown issues with the quantification of particulate chloride, resulting in apparent negative chloride concentrations. We can show that this is due to the different behavior of Cl+ and HCl+ and we present a correction for more accurate quantification of chloride. The correction can be applied for measurements in environments where the particulate chloride is dominated by NH4Cl.
TomoSim: a tomographic simulator for DOAS
Rui Valente de Almeida, Nuno Matela, and Pedro Vieira
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2020-26,2020
Preprint under review for AMT (discussion: open, 0 comments)
Air pollution is quite literally one of the most present concerns of modern day Western societies. It is widely recognized (namely by the European Union) that technology plays a very important role in the fighting of this problem. One of such technologies is the spectroscopic measurement of air pollutant concentration known as DOAS. In this paper, the technique is applied with an Unmanned Aerial Vehicle, using tomographic techniques to map pollutant concentration in two dimensions.
Mapping ice formation to mineral-surface topography using a micro mixing chamber with video and atomic-force microscopy
Raymond W. Friddle and Konrad Thürmer
Atmos. Meas. Tech., 13, 2209–2218, https://doi.org/10.5194/amt-13-2209-2020, 2020
An obstacle to predicting ice content in mixed-phase clouds is the inability to directly view atmospheric ice nucleation at the nanoscale, where this process occurs. Here we show how a cloud-like environment can be created in a small atomic-force microscopy (AFM) sample cell. By colocating video microscopy of ice formation with high-resolution AFM images, we quantitatively show how the surface topography, down to nanometer-length scales, can determine the preferential locations of ice formation.
Improved chloride quantification in quadrupole aerosol chemical speciation monitors (Q-ACSMs)
Anna K. Tobler, Alicja Skiba, Dongyu S. Wang, Philip Croteau, Katarzyna Styszko, Jarosław Nęcki, Urs Baltensperger, Jay G. Slowik, and André S. H. Prévôt
Atmos. Meas. Tech. Discuss., https//doi.org/10.5194/amt-2020-117,2020
Preprint under review for AMT (discussion: open, 0 comments)
Some quadrupole aerosol chemical speciation monitors (Q-ACSMs) have shown issues with the quantification of particulate chloride, resulting in apparent negative chloride concentrations. We can show that this is due to the different behavior of Cl+ and HCl+ and we present a correction for more accurate quantification of chloride. The correction can be applied for measurements in environments where the particulate chloride is dominated by NH4Cl.
TomoSim: a tomographic simulator for DOAS
Rui Valente de Almeida, Nuno Matela, and Pedro Vieira
Atmos. Meas. Tech. Discuss., https//doi.org/10.5194/amt-2020-26,2020
Preprint under review for AMT (discussion: open, 0 comments)
Air pollution is quite literally one of the most present concerns of modern day Western societies. It is widely recognized (namely by the European Union) that technology plays a very important role in the fighting of this problem. One of such technologies is the spectroscopic measurement of air pollutant concentration known as DOAS. In this paper, the technique is applied with an Unmanned Aerial Vehicle, using tomographic techniques to map pollutant concentration in two dimensions.
Intercomparison of NO2, O4, O3 and HCHO slant column measurements by MAX-DOAS and zenith-sky UV–visible spectrometers during CINDI-2
Karin Kreher, Michel Van Roozendael, Francois Hendrick, Arnoud Apituley, Ermioni Dimitropoulou, Udo Frieß, Andreas Richter, Thomas Wagner, Johannes Lampel, Nader Abuhassan, Li Ang, Monica Anguas, Alkis Bais, Nuria Benavent, Tim Bösch, Kristof Bognar, Alexander Borovski, Ilya Bruchkouski, Alexander Cede, Ka Lok Chan, Sebastian Donner, Theano Drosoglou, Caroline Fayt, Henning Finkenzeller, David Garcia-Nieto, Clio Gielen, Laura Gómez-Martín, Nan Hao, Bas Henzing, Jay R. Herman, Christian Hermans, Syedul Hoque, Hitoshi Irie, Junli Jin, Paul Johnston, Junaid Khayyam Butt, Fahim Khokhar, Theodore K. Koenig, Jonas Kuhn, Vinod Kumar, Cheng Liu, Jianzhong Ma, Alexis Merlaud, Abhishek K. Mishra, Moritz Müller, Monica Navarro-Comas, Mareike Ostendorf, Andrea Pazmino, Enno Peters, Gaia Pinardi, Manuel Pinharanda, Ankie Piters, Ulrich Platt, Oleg Postylyakov, Cristina Prados-Roman, Olga Puentedura, Richard Querel, Alfonso Saiz-Lopez, Anja Schönhardt, Stefan F. Schreier, André Seyler, Vinayak Sinha, Elena Spinei, Kimberly Strong, Frederik Tack, Xin Tian, Martin Tiefengraber, Jan-Lukas Tirpitz, Jeroen van Gent, Rainer Volkamer, Mihalis Vrekoussis, Shanshan Wang, Zhuoru Wang, Mark Wenig, Folkard Wittrock, Pinhua H. Xie, Jin Xu, Margarita Yela, Chengxin Zhang, and Xiaoyi Zhao
Atmos. Meas. Tech., 13, 2169–2208, https://doi.org/10.5194/amt-13-2169-2020, 2020
In September 2016, 36 spectrometers from 24 institutes measured a number of key atmospheric pollutants during an instrument intercomparison campaign (CINDI-2) at Cabauw, the Netherlands. Here we report on the outcome of this intercomparison exercise. The three major goals were to characterise the differences between the participating instruments, to define a robust methodology for performance assessment, and to contribute to the harmonisation of the measurement settings and retrieval methods.
Variability of the Brunt-Väisälä frequency at the OH-airglow layer
height at low and mid latitudes
Sabine Wüst, Michael Bittner, Jeng-Hwa Yee, Martin G. Mlynczak, and James M. Russell III
Atmos. Meas. Tech. Discuss., https//doi.org/10.5194/amt-2020-73,2020
Preprint under review for AMT (discussion: open, 0 comments)
With airglow spectrometers the temperature in the upper mesosphere/lower thermosphere can be derived each night. The data allow to estimate the amount of energy which is transported by small-scale atmospheric waves, known as gravity waves. In order to do this, information about the Brunt–Väisälä frequency and its evolution during the year is necessary. This is provided here for low and mid latitudes based on 18 years of satellite data.
Three Decades of Tropospheric Ozone Lidar Development at Garmisch-Partenkirchen
Thomas Trickl, Helmuth Giehl, Frank Neidl, Matthias Perfahl, and Hannes Vogelmann
Atmos. Meas. Tech. Discuss., https//doi.org/10.5194/amt-2020-89,2020
Preprint under review for AMT (discussion: open, 0 comments)
Lidar sounding of ozone and other atmospheric constituents has proved to be invaluable tool for atmospheric studies. The ozone lidar systems developed at Garmisch-Partenkirchen have reached an accuracy level almost matching that of in situ sensors. Since the late 1990s numerous important scientific discoveries have been made such as the first observation of intercontinental transport of ozone and the very high occurrence of intrusions of stratospheric air into the troposphere.
Intercomparison of NO2, O4, O3 and HCHO slant column measurements by MAX-DOAS and zenith-sky UV–visible spectrometers during CINDI-2
Karin Kreher, Michel Van Roozendael, Francois Hendrick, Arnoud Apituley, Ermioni Dimitropoulou, Udo Frieß, Andreas Richter, Thomas Wagner, Johannes Lampel, Nader Abuhassan, Li Ang, Monica Anguas, Alkis Bais, Nuria Benavent, Tim Bösch, Kristof Bognar, Alexander Borovski, Ilya Bruchkouski, Alexander Cede, Ka Lok Chan, Sebastian Donner, Theano Drosoglou, Caroline Fayt, Henning Finkenzeller, David Garcia-Nieto, Clio Gielen, Laura Gómez-Martín, Nan Hao, Bas Henzing, Jay R. Herman, Christian Hermans, Syedul Hoque, Hitoshi Irie, Junli Jin, Paul Johnston, Junaid Khayyam Butt, Fahim Khokhar, Theodore K. Koenig, Jonas Kuhn, Vinod Kumar, Cheng Liu, Jianzhong Ma, Alexis Merlaud, Abhishek K. Mishra, Moritz Müller, Monica Navarro-Comas, Mareike Ostendorf, Andrea Pazmino, Enno Peters, Gaia Pinardi, Manuel Pinharanda, Ankie Piters, Ulrich Platt, Oleg Postylyakov, Cristina Prados-Roman, Olga Puentedura, Richard Querel, Alfonso Saiz-Lopez, Anja Schönhardt, Stefan F. Schreier, André Seyler, Vinayak Sinha, Elena Spinei, Kimberly Strong, Frederik Tack, Xin Tian, Martin Tiefengraber, Jan-Lukas Tirpitz, Jeroen van Gent, Rainer Volkamer, Mihalis Vrekoussis, Shanshan Wang, Zhuoru Wang, Mark Wenig, Folkard Wittrock, Pinhua H. Xie, Jin Xu, Margarita Yela, Chengxin Zhang, and Xiaoyi Zhao
Atmos. Meas. Tech., 13, 2169–2208, https://doi.org/10.5194/amt-13-2169-2020, 2020
In September 2016, 36 spectrometers from 24 institutes measured a number of key atmospheric pollutants during an instrument intercomparison campaign (CINDI-2) at Cabauw, the Netherlands. Here we report on the outcome of this intercomparison exercise. The three major goals were to characterise the differences between the participating instruments, to define a robust methodology for performance assessment, and to contribute to the harmonisation of the measurement settings and retrieval methods.
Global Cloud Property Models for Real Time Triage Onboard Visible-Shortwave Infrared Spectrometers
Macey W. Sandford, David R. Thompson, Robert O. Green, Brian H. Kahn, Raffaele Vitulli, Steve Chien, Amruta Yelamanchili, and Winston Olson-Duvall
Atmos. Meas. Tech. Discuss., https//doi.org/10.5194/amt-2020-139,2020
Preprint under review for AMT (discussion: open, 0 comments)
We demonstrate an onboard cloud screening approach to significantly reduce the amount of cloud-contaminated data transmitted from orbit. We have produced location-specific models that improve performance by taking into account the unique cloud statistics in different latitudes. We have shown that screening clouds based on their location or surface type will improve the ability for a cloud-screening tool to improve the volume of usable science data.
Global Cloud Property Models for Real Time Triage Onboard Visible-Shortwave Infrared Spectrometers
Macey W. Sandford, David R. Thompson, Robert O. Green, Brian H. Kahn, Raffaele Vitulli, Steve Chien, Amruta Yelamanchili, and Winston Olson-Duvall
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2020-139,2020
Preprint under review for AMT (discussion: open, 0 comments)
We demonstrate an onboard cloud screening approach to significantly reduce the amount of cloud-contaminated data transmitted from orbit. We have produced location-specific models that improve performance by taking into account the unique cloud statistics in different latitudes. We have shown that screening clouds based on their location or surface type will improve the ability for a cloud-screening tool to improve the volume of usable science data.
Variability of the Brunt-Väisälä frequency at the OH-airglow layer
height at low and mid latitudes
Sabine Wüst, Michael Bittner, Jeng-Hwa Yee, Martin G. Mlynczak, and James M. Russell III
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2020-73,2020
Preprint under review for AMT (discussion: open, 0 comments)
With airglow spectrometers the temperature in the upper mesosphere/lower thermosphere can be derived each night. The data allow to estimate the amount of energy which is transported by small-scale atmospheric waves, known as gravity waves. In order to do this, information about the Brunt–Väisälä frequency and its evolution during the year is necessary. This is provided here for low and mid latitudes based on 18 years of satellite data.
Three Decades of Tropospheric Ozone Lidar Development at Garmisch-Partenkirchen
Thomas Trickl, Helmuth Giehl, Frank Neidl, Matthias Perfahl, and Hannes Vogelmann
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2020-89,2020
Preprint under review for AMT (discussion: open, 0 comments)
Lidar sounding of ozone and other atmospheric constituents has proved to be invaluable tool for atmospheric studies. The ozone lidar systems developed at Garmisch-Partenkirchen have reached an accuracy level almost matching that of in situ sensors. Since the late 1990s numerous important scientific discoveries have been made such as the first observation of intercontinental transport of ozone and the very high occurrence of intrusions of stratospheric air into the troposphere.
The influence of the baseline drift on the resulting extinction values of a cavity attenuated phase shift-based extinction monitor (CAPS PMex)
Sascha Pfeifer, Thomas Müller, Andrew Freedman, and Alfred Wiedensohler
Atmos. Meas. Tech., 13, 2161–2167, https://doi.org/10.5194/amt-13-2161-2020, 2020
The effect of the baseline drift on the resulting extinction values of three CAPS PMex monitors with different wavelengths was analysed for an urban background station. A significant baseline drift was observed, which leads to characteristic measurement artefacts for particle extinction. Two alternative methods for recalculating the baseline are shown. With these methods the extinction artefacts are diminished and the effective scattering of the resulting extinction values is reduced.
How to estimate total differential attenuation due to hydrometeors with ground-based multi-frequency radars?
Frédéric Tridon, Alessandro Battaglia, and Stefan Kneifel
Atmos. Meas. Tech. Discuss., https//doi.org/10.5194/amt-2020-159,2020
Preprint under review for AMT (discussion: open, 0 comments)
At millimeter wavelengths, attenuation by hydrometeors, such as liquid droplets or large snowflakes, is generally not negligible. When using multi-frequency ground-based radar measurements, it is common practice to use the Rayleigh targets at cloud top as a reference in order to derive attenuation-corrected reflectivities and meaningful dual-frequency ratios (DFR). By capitalizing on this idea, this study describes a new quality-controlled approach aiming at identifying regions of the cloud where particle growth is negligible. The core of the method is the identification of a Rayleigh plateau, i.e. a large enough region near cloud top where the vertical gradient of DFR remains small.
By analyzing collocated Ka-W band radar and microwave radiometer (MWR) observations taken at two European sites under various meteorological conditions, it is shown how the resulting estimates of differential path-integrated attenuation (DeltaPIA) can be used to characterize hydrometeor properties. When the DeltaPIA is predominantly produced by cloud liquid droplets, this technique alone can provide accurate estimates of the liquid water path. When combined with MWR observations, this methodology paves the way towards profiling the cloud liquid water and/or quality flagging the MWR retrieval for rain/drizzle contamination and/or estimating the snow differential attenuation.
The influence of the baseline drift on the resulting extinction values of a cavity attenuated phase shift-based extinction monitor (CAPS PMex)
Sascha Pfeifer, Thomas Müller, Andrew Freedman, and Alfred Wiedensohler
Atmos. Meas. Tech., 13, 2161–2167, https://doi.org/10.5194/amt-13-2161-2020, 2020
The effect of the baseline drift on the resulting extinction values of three CAPS PMex monitors with different wavelengths was analysed for an urban background station. A significant baseline drift was observed, which leads to characteristic measurement artefacts for particle extinction. Two alternative methods for recalculating the baseline are shown. With these methods the extinction artefacts are diminished and the effective scattering of the resulting extinction values is reduced.
How to estimate total differential attenuation due to hydrometeors with ground-based multi-frequency radars?
Frédéric Tridon, Alessandro Battaglia, and Stefan Kneifel
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2020-159,2020
Preprint under review for AMT (discussion: open, 0 comments)
At millimeter wavelengths, attenuation by hydrometeors, such as liquid droplets or large snowflakes, is generally not negligible. When using multi-frequency ground-based radar measurements, it is common practice to use the Rayleigh targets at cloud top as a reference in order to derive attenuation-corrected reflectivities and meaningful dual-frequency ratios (DFR). By capitalizing on this idea, this study describes a new quality-controlled approach aiming at identifying regions of the cloud where particle growth is negligible. The core of the method is the identification of a Rayleigh plateau, i.e. a large enough region near cloud top where the vertical gradient of DFR remains small.
By analyzing collocated Ka-W band radar and microwave radiometer (MWR) observations taken at two European sites under various meteorological conditions, it is shown how the resulting estimates of differential path-integrated attenuation (DeltaPIA) can be used to characterize hydrometeor properties. When the DeltaPIA is predominantly produced by cloud liquid droplets, this technique alone can provide accurate estimates of the liquid water path. When combined with MWR observations, this methodology paves the way towards profiling the cloud liquid water and/or quality flagging the MWR retrieval for rain/drizzle contamination and/or estimating the snow differential attenuation.
