A new method to correct the ECC ozone sonde time response and its implications for “background current” and pump efficiency
Holger Vömel, Herman G. J. Smit, David Tarasick, Bryan Johnson, Samuel J. Oltmans, Henry Selkirk, Anne M. Thompson, Ryan M. Stauffer, Jacquelyn C. Witte, Jonathan Davies, Roeland van Malderen, Gary A. Morris, Tatsumi Nakano, and Rene Stübi
Atmos. Meas. Tech. Discuss., https//doi.org/10.5194/amt-2020-62,2020
Preprint under review for AMT (discussion: open, 0 comments)
The time response of Electrochemical Concentration Cell (ECC) ozone sondes points to at least two distinct reaction pathways with time constants of approximately 20 s and 25 min. Properly considering these time constants eliminates the need for a poorly defined "background" and allows reducing ad-hoc corrections based on laboratory tests. This reduces the uncertainty of ECC ozone sonde measurements throughout the profile and especially in regions of low ozone and strong gradients of ozone.
In-orbit Earth reflectance validation of TROPOMI on board the Sentinel-5 Precursor satellite
Lieuwe G. Tilstra, Martin de Graaf, Ping Wang, and Piet Stammes
Atmos. Meas. Tech. Discuss., https//doi.org/10.5194/amt-2020-98,2020
Preprint under review for AMT (discussion: open, 0 comments)
The goal of the study was to determine the accuracy of the radiometric calibration of the TROPOMI instrument on board the Sentinel-5 Precursor satellite in-flight. The Earth reflectances were compared to radiative transfer calculations. We report calibration accuracies and errors for 21 selected wavelength bands between 328 and 2314 nm, located in TROPOMI spectral bands 3–7. The reported numbers can be used to perform corrections that will benefit the retrievals of many atmospheric properties.
An instrument for in situ measurement of total ozone reactivity
Roberto Sommariva, Louisa J. Kramer, Leigh R. Crilley, Mohammed S. Alam, and William J. Bloss
Atmos. Meas. Tech., 13, 1655–1670, https://doi.org/10.5194/amt-13-1655-2020, 2020
Ozone is a key atmospheric pollutant formed through chemical processing of natural and anthropogenic emissions and removed by reaction with organic compounds emitted by plants. We describe a new instrument – the Total Ozone Reactivity System or TORS – that measures the total loss of ozone in the troposphere. The objective of the TORS instrument is to provide an estimate of the organic compounds emitted by plants which are not measured and thus to improve our understanding of the ozone budget.
Comparison of GTO-ECV and adjusted MERRA-2 total ozone columns from the last 2 decades and assessment of interannual variability
Melanie Coldewey-Egbers, Diego G. Loyola, Gordon Labow, and Stacey M. Frith
Atmos. Meas. Tech., 13, 1633–1654, https://doi.org/10.5194/amt-13-1633-2020, 2020
We compare total ozone columns from the satellite-based GOME-type Total Ozone Essential Climate Variable record and the adjusted 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.
A compact Incoherent Broadband Cavity Enhanced Absorption
Spectrometer (IBBCEAS) for trace detection of nitrogen oxides,
iodine oxide and glyoxal at sub-ppb levels for field application
Albane Barbero, Camille Blouzon, Joël Savarino, Nicolas Caillon, Aurélien Dommergue, and Roberto Grilli
Atmos. Meas. Tech. Discuss., https//doi.org/10.5194/amt-2020-104,2020
Preprint under review for AMT (discussion: open, 0 comments)
In this manuscript, we present a compact, affordable and robust instrument for in situ measurements of different trace gases: NOx, IO, CHOCHO and O3 with very low detection limits. The device weights 15 kg and has a total electrical power consumption < 300 W. Its detection limits are very low making the instrument suitable to address different questions such as better constraint the oxidative capacity of the atmosphere and study the chemistry of highly reactive species.
Improving GOES Advanced Baseline Imager (ABI) Aerosol Optical Depth (AOD) Retrievals using an Empirical Bias Correction Algorithm
Hai Zhang, Shobha Kondragunta, Istvan Laszlo, and Mi Zhou
Atmos. Meas. Tech. Discuss., https//doi.org/10.5194/amt-2020-115,2020
Preprint under review for AMT (discussion: open, 0 comments)
The Advanced Baseline Imager (ABI) on board the Geostationary Operational Environmental Satellite-R (GOES-R) series enables retrieval of aerosol optical depth (AOD) from geostationary satellites using a multi-band algorithm similar to those of polar-orbiting satellites’ sensors, such as the Moderate Resolution Imaging Spectroradiometer (MODIS) and Visible Infrared Imaging Radiometer Suite (VIIRS). Therefore, ABI AOD is expected to have accuracy and precision comparable to MODIS AOD and VIIRS AOD. However, this work demonstrates that the current version of GOES-16 (GOES-East) ABI AOD has diurnally varying biases due to errors in the land surface reflectance relationship between the bands used in the ABI AOD retrieval algorithm, which vary with respect to the Sun-satellite geometry. To reduce these biases, an empirical bias correction algorithm has been developed based on the lowest observed ABI AOD of an adjacent 30-day period and the background AOD at each time step and at each pixel. The bias correction algorithm improves the performance of ABI AOD compared to AErosol RObotic NETwork (AERONET) AOD, especially for the high and medium (top 2) quality ABI AOD. AOD data for the period August 6 to December 31, 2018 are used to validate the bias correction algorithm. For the top 2 qualities ABI AOD, after bias correction, the correlation between ABI AOD and AERONET AOD improves from 0.87 to 0.91, the mean bias improves from 0.04 to 0.00, and root mean square error (RMSE) improves from 0.09 to 0.05. These results for the bias corrected top 2 qualities ABI AOD are comparable to those of the uncorrected high-quality ABI AOD. Thus, by using the top 2 qualities of ABI AOD in conjunction with the bias correction algorithm, the area coverage of ABI AOD is substantially increased without loss of data accuracy.
A compact Incoherent Broadband Cavity Enhanced Absorption
Spectrometer (IBBCEAS) for trace detection of nitrogen oxides,
iodine oxide and glyoxal at sub-ppb levels for field application
Albane Barbero, Camille Blouzon, Joël Savarino, Nicolas Caillon, Aurélien Dommergue, and Roberto Grilli
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2020-104,2020
Preprint under review for AMT (discussion: open, 0 comments)
In this manuscript, we present a compact, affordable and robust instrument for in situ measurements of different trace gases: NOx, IO, CHOCHO and O3 with very low detection limits. The device weights 15 kg and has a total electrical power consumption < 300 W. Its detection limits are very low making the instrument suitable to address different questions such as better constraint the oxidative capacity of the atmosphere and study the chemistry of highly reactive species.
Improving GOES Advanced Baseline Imager (ABI) Aerosol Optical Depth (AOD) Retrievals using an Empirical Bias Correction Algorithm
Hai Zhang, Shobha Kondragunta, Istvan Laszlo, and Mi Zhou
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2020-115,2020
Preprint under review for AMT (discussion: open, 0 comments)
The Advanced Baseline Imager (ABI) on board the Geostationary Operational Environmental Satellite-R (GOES-R) series enables retrieval of aerosol optical depth (AOD) from geostationary satellites using a multi-band algorithm similar to those of polar-orbiting satellites’ sensors, such as the Moderate Resolution Imaging Spectroradiometer (MODIS) and Visible Infrared Imaging Radiometer Suite (VIIRS). Therefore, ABI AOD is expected to have accuracy and precision comparable to MODIS AOD and VIIRS AOD. However, this work demonstrates that the current version of GOES-16 (GOES-East) ABI AOD has diurnally varying biases due to errors in the land surface reflectance relationship between the bands used in the ABI AOD retrieval algorithm, which vary with respect to the Sun-satellite geometry. To reduce these biases, an empirical bias correction algorithm has been developed based on the lowest observed ABI AOD of an adjacent 30-day period and the background AOD at each time step and at each pixel. The bias correction algorithm improves the performance of ABI AOD compared to AErosol RObotic NETwork (AERONET) AOD, especially for the high and medium (top 2) quality ABI AOD. AOD data for the period August 6 to December 31, 2018 are used to validate the bias correction algorithm. For the top 2 qualities ABI AOD, after bias correction, the correlation between ABI AOD and AERONET AOD improves from 0.87 to 0.91, the mean bias improves from 0.04 to 0.00, and root mean square error (RMSE) improves from 0.09 to 0.05. These results for the bias corrected top 2 qualities ABI AOD are comparable to those of the uncorrected high-quality ABI AOD. Thus, by using the top 2 qualities of ABI AOD in conjunction with the bias correction algorithm, the area coverage of ABI AOD is substantially increased without loss of data accuracy.
An LES-based airborne Doppler lidar simulator and its application to wind profiling in inhomogeneous flow conditions
Philipp Gasch, Andreas Wieser, Julie K. Lundquist, and Norbert Kalthoff
Atmos. Meas. Tech., 13, 1609–1631, https://doi.org/10.5194/amt-13-1609-2020, 2020
We present an airborne Doppler lidar simulator (ADLS) based on high-resolution atmospheric wind fields (LES). The ADLS is used to evaluate the retrieval accuracy of airborne wind profiling under turbulent, inhomogeneous wind field conditions inside the boundary layer. With the ADLS, the error due to the violation of the wind field homogeneity assumption used for retrieval can be revealed. For the conditions considered, flow inhomogeneities exert a dominant influence on wind profiling error.
Towards objective identification and tracking of convective outflow boundaries in next-generation geostationary satellite imagery
Jason M. Apke, Kyle A. Hilburn, Steven D. Miller, and David A. Peterson
Atmos. Meas. Tech., 13, 1593–1608, https://doi.org/10.5194/amt-13-1593-2020, 2020
Objective identification of deep convection outflow boundaries (OFBs) in next-generation geostationary satellite imagery is explored here using motion derived from a tuned advanced optical flow algorithm. Motion discontinuity preservation within the derivation is found crucial for successful OFB tracking between images, which yields new meteorological data for objective systems to use. These results provide the first step towards a fully automated satellite-based OFB identification algorithm.
An instrument for in situ measurement of total ozone reactivity
Roberto Sommariva, Louisa J. Kramer, Leigh R. Crilley, Mohammed S. Alam, and William J. Bloss
Atmos. Meas. Tech., 13, 1655–1670, https://doi.org/10.5194/amt-13-1655-2020, 2020
Ozone is a key atmospheric pollutant formed through chemical processing of natural and anthropogenic emissions and removed by reaction with organic compounds emitted by plants. We describe a new instrument – the Total Ozone Reactivity System or TORS – that measures the total loss of ozone in the troposphere. The objective of the TORS instrument is to provide an estimate of the organic compounds emitted by plants which are not measured and thus to improve our understanding of the ozone budget.
Comparison of GTO-ECV and adjusted MERRA-2 total ozone columns from the last 2 decades and assessment of interannual variability
Melanie Coldewey-Egbers, Diego G. Loyola, Gordon Labow, and Stacey M. Frith
Atmos. Meas. Tech., 13, 1633–1654, https://doi.org/10.5194/amt-13-1633-2020, 2020
We compare total ozone columns from the satellite-based GOME-type Total Ozone Essential Climate Variable record and the adjusted 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.
An LES-based airborne Doppler lidar simulator and its application to wind profiling in inhomogeneous flow conditions
Philipp Gasch, Andreas Wieser, Julie K. Lundquist, and Norbert Kalthoff
Atmos. Meas. Tech., 13, 1609–1631, https://doi.org/10.5194/amt-13-1609-2020, 2020
We present an airborne Doppler lidar simulator (ADLS) based on high-resolution atmospheric wind fields (LES). The ADLS is used to evaluate the retrieval accuracy of airborne wind profiling under turbulent, inhomogeneous wind field conditions inside the boundary layer. With the ADLS, the error due to the violation of the wind field homogeneity assumption used for retrieval can be revealed. For the conditions considered, flow inhomogeneities exert a dominant influence on wind profiling error.
Towards objective identification and tracking of convective outflow boundaries in next-generation geostationary satellite imagery
Jason M. Apke, Kyle A. Hilburn, Steven D. Miller, and David A. Peterson
Atmos. Meas. Tech., 13, 1593–1608, https://doi.org/10.5194/amt-13-1593-2020, 2020
Objective identification of deep convection outflow boundaries (OFBs) in next-generation geostationary satellite imagery is explored here using motion derived from a tuned advanced optical flow algorithm. Motion discontinuity preservation within the derivation is found crucial for successful OFB tracking between images, which yields new meteorological data for objective systems to use. These results provide the first step towards a fully automated satellite-based OFB identification algorithm.
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., 13, 1575–1591, https://doi.org/10.5194/amt-13-1575-2020, 2020
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) on board 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.
Distributed observations of wind direction using microstructures attached to actively heated fiber-optic cables
Karl Lapo, Anita Freundorfer, Lena Pfister, Johann Schneider, John Selker, and Christoph Thomas
Atmos. Meas. Tech., 13, 1563–1573, https://doi.org/10.5194/amt-13-1563-2020, 2020
Most observations of the atmosphere are point observations, which only measure a small area around the sensor. This limitation creates problems for a number of disciplines, especially those that focus on how the surface and atmosphere exchange heat, mass, and momentum. We used distributed temperature sensing with fiber optics to demonstrate a key breakthrough in observing wind direction in a distributed way, i.e., not at a point, using small structures attached to the fiber-optic cables.
Development of a new nanoparticle sizer equipped with a 12-channel multi-port differential mobility analyzer and multi-condensation particle counters
Hong Ku Lee, Handol Lee, and Kang-Ho Ahn
Atmos. Meas. Tech., 13, 1551–1562, https://doi.org/10.5194/amt-13-1551-2020, 2020
We developed a nanoparticle sizer (NPS), consisting of a multi-port differential mobility analyzer (MP-DMA) with 12 sampling ports and multi-condensation particle counters (M-CPCs) for fast measurement of particle size distribution. The NPS can successfully capture the changes in particle size distribution under fast-changing particle concentration conditions. In this study, particle emissions from cooking activity are analyzed as an exemplary real-world application.
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., 13, 1575–1591, https://doi.org/10.5194/amt-13-1575-2020, 2020
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) on board 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.
Distributed observations of wind direction using microstructures attached to actively heated fiber-optic cables
Karl Lapo, Anita Freundorfer, Lena Pfister, Johann Schneider, John Selker, and Christoph Thomas
Atmos. Meas. Tech., 13, 1563–1573, https://doi.org/10.5194/amt-13-1563-2020, 2020
Most observations of the atmosphere are point observations, which only measure a small area around the sensor. This limitation creates problems for a number of disciplines, especially those that focus on how the surface and atmosphere exchange heat, mass, and momentum. We used distributed temperature sensing with fiber optics to demonstrate a key breakthrough in observing wind direction in a distributed way, i.e., not at a point, using small structures attached to the fiber-optic cables.
Development of a new nanoparticle sizer equipped with a 12-channel multi-port differential mobility analyzer and multi-condensation particle counters
Hong Ku Lee, Handol Lee, and Kang-Ho Ahn
Atmos. Meas. Tech., 13, 1551–1562, https://doi.org/10.5194/amt-13-1551-2020, 2020
We developed a nanoparticle sizer (NPS), consisting of a multi-port differential mobility analyzer (MP-DMA) with 12 sampling ports and multi-condensation particle counters (M-CPCs) for fast measurement of particle size distribution. The NPS can successfully capture the changes in particle size distribution under fast-changing particle concentration conditions. In this study, particle emissions from cooking activity are analyzed as an exemplary real-world application.
