Probabilistic analysis of ambiguities in radar echo direction of
arrival from meteors
Daniel Kastinen and Johan Kero
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2020-157,2020
Preprint under review for AMT (discussion: open, 0 comments)
The behavior of position determination with interferometric radar systems and possible ambiguities therein depend on the spatial configuration of the radar receiving antennas and their individual characteristics. We have simulated the position determination performance of five different radar systems. These simulation showed that ambiguities are dynamic and need to be examined on a case by case basis. However, the simulations can be used to analyse and understand previously ambiguous data.
Effects of clouds on the UV Absorbing Aerosol Index from TROPOMI
Maurits L. Kooreman, Piet Stammes, Victor Trees, Maarten Sneep, L. Gijsbert Tilstra, Martin de Graaf, Deborah C. Stein Zweers, Ping Wang, Olaf N. E. Tuinder, and J. Pepijn Veefkind
Atmos. Meas. Tech. Discuss., https//doi.org/10.5194/amt-2020-112,2020
Preprint under review for AMT (discussion: open, 0 comments)
We investigated the influence of clouds on the AAI, which is an indicator of the presence of small particles suspended in the atmosphere. Clouds produce artefacts in the AAI calculation on the individual measurement (7 km) scale, which was not seen with previous instruments, as well as large (1000+ km) scales. To reduce these artefacts, we used three different AAI calculation techniques with varying complexity. We find that the AAI artefacts are reduced when using more complex techniques.
Retrieval of Lower-Order Moments of the Drop Size Distribution using CSU-CHILL X-band Polarimetric Radar: A Case Study
Viswanathan Bringi, Kumar Vijay Mishra, Merhala Thurai, Patrick C. Kennedy, and Timothy H. Raupach
Atmos. Meas. Tech. Discuss., https//doi.org/10.5194/amt-2020-160,2020
Preprint under review for AMT (discussion: open, 0 comments)
The raindrop size distribution and its moments are fundamental in many areas such as radar measurement of rainfall using polarimetry and numerical modelling of the microphysical processes of rain formation and evolution. We develop a technique which uses advanced radar measurements and complete drop size distributions using two collocated instruments to retrieve the lower order moments such as total drop concentration and rain water content. We demonstrate proof-of-concept using a case study.
Probabilistic analysis of ambiguities in radar echo direction of
arrival from meteors
Daniel Kastinen and Johan Kero
Atmos. Meas. Tech. Discuss., https//doi.org/10.5194/amt-2020-157,2020
Preprint under review for AMT (discussion: open, 0 comments)
The behavior of position determination with interferometric radar systems and possible ambiguities therein depend on the spatial configuration of the radar receiving antennas and their individual characteristics. We have simulated the position determination performance of five different radar systems. These simulation showed that ambiguities are dynamic and need to be examined on a case by case basis. However, the simulations can be used to analyse and understand previously ambiguous data.
Removing spurious inertial instability signals from gravity wave
temperature perturbations using spectral filtering methods
Cornelia Strube, Manfred Ern, Peter Preusse, and Martin Riese
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2020-29,2020
Preprint under review for AMT (discussion: open, 1 comment)
We present how inertial instabilities affect gravity wave background removals on different temperature data sets. Vertical filtering has to remove a part of the gravity wave spectrum to eliminate inertial instability remnants, while horizontal filtering leaves typical gravity wave scales untouched. In addition, we show that it is possible to separate inertial instabilities from gravity wave perturbations for infrared limb-sounding satellite profiles using a cutoff zonal wavenumber of 6.
Combining low-cost, surface-based aerosol monitors with
size-resolved satellite data for air quality applications
Priyanka deSouza, Ralph A. Kahn, James A. Limbacher, Eloise A. Marais, Fábio Duarte, and Carlo Ratti
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2020-136,2020
Preprint under review for AMT (discussion: open, 0 comments)
This paper presents a novel method to calibrate satellite data using low-cost optical particle counters (OPCs) to develop higher quality particulate matter (PM) estimates. This method could enable cities that do not have access to expensive reference air quality monitors, many of which are in the global South, to develop locally calibrated PM estimates from satellite data. Such information can be crucial for the development of effective air quality management plans.
Combining low-cost, surface-based aerosol monitors with
size-resolved satellite data for air quality applications
Priyanka deSouza, Ralph A. Kahn, James A. Limbacher, Eloise A. Marais, Fábio Duarte, and Carlo Ratti
Atmos. Meas. Tech. Discuss., https//doi.org/10.5194/amt-2020-136,2020
Preprint under review for AMT (discussion: open, 0 comments)
This paper presents a novel method to calibrate satellite data using low-cost optical particle counters (OPCs) to develop higher quality particulate matter (PM) estimates. This method could enable cities that do not have access to expensive reference air quality monitors, many of which are in the global South, to develop locally calibrated PM estimates from satellite data. Such information can be crucial for the development of effective air quality management plans.
Removing spurious inertial instability signals from gravity wave
temperature perturbations using spectral filtering methods
Cornelia Strube, Manfred Ern, Peter Preusse, and Martin Riese
Atmos. Meas. Tech. Discuss., https//doi.org/10.5194/amt-2020-29,2020
Preprint under review for AMT (discussion: open, 1 comment)
We present how inertial instabilities affect gravity wave background removals on different temperature data sets. Vertical filtering has to remove a part of the gravity wave spectrum to eliminate inertial instability remnants, while horizontal filtering leaves typical gravity wave scales untouched. In addition, we show that it is possible to separate inertial instabilities from gravity wave perturbations for infrared limb-sounding satellite profiles using a cutoff zonal wavenumber of 6.
An improved TROPOMI tropospheric HCHO retrieval over China
Wenjing Su, Cheng Liu, Ka Lok Chan, Qihou Hu, Haoran Liu, Xiangguang Ji, Yizhi Zhu, Ting Liu, Chengxin Zhang, Yujia Chen, and Jianguo Liu
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2020-109,2020
Preprint under review for AMT (discussion: open, 0 comments)
The manuscript presents an improved retrieval of TROPOMI tropospheric HCHO column over China. The new retrieval optimized both slant column retrieval and air mass factor calculation for TROPOMI observations of HCHO over China. The improved TROPOMI HCHO is subsequently validated by MAX-DOAS observations. Compared to the operational product, the improved HCHO agrees better to the MAX-DOAS data and thus better suit for the analysis of regional and city scale pollution in China.
An improved TROPOMI tropospheric HCHO retrieval over China
Wenjing Su, Cheng Liu, Ka Lok Chan, Qihou Hu, Haoran Liu, Xiangguang Ji, Yizhi Zhu, Ting Liu, Chengxin Zhang, Yujia Chen, and Jianguo Liu
Atmos. Meas. Tech. Discuss., https//doi.org/10.5194/amt-2020-109,2020
Preprint under review for AMT (discussion: open, 0 comments)
The manuscript presents an improved retrieval of TROPOMI tropospheric HCHO column over China. The new retrieval optimized both slant column retrieval and air mass factor calculation for TROPOMI observations of HCHO over China. The improved TROPOMI HCHO is subsequently validated by MAX-DOAS observations. Compared to the operational product, the improved HCHO agrees better to the MAX-DOAS data and thus better suit for the analysis of regional and city scale pollution in China.
Shallow cumuli cover and its uncertainties from ground-based lidar–radar data and sky images
Erin A. Riley, Jessica M. Kleiss, Laura D. Riihimaki, Charles N. Long, Larry K. Berg, and Evgueni Kassianov
Atmos. Meas. Tech., 13, 2099–2117, https://doi.org/10.5194/amt-13-2099-2020, 2020
Discrepancies in hourly shallow cumuli cover estimates can be substantial. Instrument detection differences contribute to long-term bias in shallow cumuli cover estimates, whereas narrow field-of-view configurations impact measurement uncertainty as averaging time decreases. A new tool is introduced to visually assess both impacts on sub-hourly cloud cover estimates. Accurate shallow cumuli cover estimation is needed for model–observation comparisons and studying cloud-surface interactions.
Shallow cumuli cover and its uncertainties from ground-based lidar–radar data and sky images
Erin A. Riley, Jessica M. Kleiss, Laura D. Riihimaki, Charles N. Long, Larry K. Berg, and Evgueni Kassianov
Atmos. Meas. Tech., 13, 2099–2117, https://doi.org/10.5194/amt-13-2099-2020, 2020
Discrepancies in hourly shallow cumuli cover estimates can be substantial. Instrument detection differences contribute to long-term bias in shallow cumuli cover estimates, whereas narrow field-of-view configurations impact measurement uncertainty as averaging time decreases. A new tool is introduced to visually assess both impacts on sub-hourly cloud cover estimates. Accurate shallow cumuli cover estimation is needed for model–observation comparisons and studying cloud-surface interactions.
Intercomparison of wind observations from the European Space Agency's Aeolus satellite mission and the ALADIN Airborne Demonstrator
Oliver Lux, Christian Lemmerz, Fabian Weiler, Uwe Marksteiner, Benjamin Witschas, Stephan Rahm, Alexander Geiß, and Oliver Reitebuch
Atmos. Meas. Tech., 13, 2075–2097, https://doi.org/10.5194/amt-13-2075-2020, 2020
This work reports on the first airborne validation campaign of ESA’s Earth Explorer mission Aeolus, conducted in central Europe during the commissioning phase in November 2018. After presenting the methodology used to compare the data sets from the satellite, the airborne wind lidar and the ECWMF model, the wind results from the underflights performed are analyzed and discussed, providing a first assessment of the accuracy and precision of the preliminary Aeolus wind data.
Implementation of an IBBCEAS technique in an atmospheric simulation chamber for in situ NO3 monitoring: characterization and validation for kinetic studies
Axel Fouqueau, Manuela Cirtog, Mathieu Cazaunau, Edouard Pangui, Pascal Zapf, Guillaume Siour, Xavier Landsheere, Guillaume Méjean, Daniele Romanini, and Bénédicte Picquet-Varrault
Atmos. Meas. Tech. Discuss., https//doi.org/10.5194/amt-2020-103,2020
Preprint under review for AMT (discussion: open, 0 comments)
An incoherent broadband cavity-enhanced absorption spectroscopy (IBBCEAS) technique has been developed for in situ monitoring of NO3 radicals in the CSA simulation chamber (at LISA). The optical cavity allows a high sensitivity for NO3 detection up to 6 ppt for an integration time of 10 seconds. The technique is now fully operational and can be used to determine rate constants for fast reactions involving complex volatile organic compounds (with rate constants up to 10-10 cm3 molecule-1 s-1).
Microwave single scattering properties of non-spheroidal rain drops
Robin Ekelund, Patrick Eriksson, and Michael Kahnert
Atmos. Meas. Tech. Discuss., https//doi.org/10.5194/amt-2020-85,2020
Preprint under review for AMT (discussion: open, 0 comments)
Rain drops become flattened due to aerodynamic drag, as they increase in mass and fall-speed. The shape of such rain drops was calculated, and the electromagnetic interaction between microwave radiation and the rain drops was calculated. The calculations are made publicly available to the scientific community, in order to promote accurate representations of rain drops in measurements. Tests show that the drop shape can indeed have a noticeable effect on microwave observations of heavy rainfall.
Uncertainty Quantification for Atmospheric Motion Vectors with Machine Learning
Joaquim V. Teixeira, Hai Nguyen, Derek J. Posselt, Hui Su, and Longtao Wu
Atmos. Meas. Tech. Discuss., https//doi.org/10.5194/amt-2020-95,2020
Preprint under review for AMT (discussion: open, 0 comments)
Wind-tracking algorithms produce atmospheric motion vectors (AMVs) by tracking satellite observations. Accurately characterizing the uncertainties in AMVs is essential in assimilating them into data assimilation models. We develop a machine learning based approach for error characterization which involves gaussian mixture model clustering and random forest using a simulation dataset of water vapor, AMVs, and true winds. We show that our method improves on existing AMV error characterizations.
Intercomparison of wind observations from the European Space Agency's Aeolus satellite mission and the ALADIN Airborne Demonstrator
Oliver Lux, Christian Lemmerz, Fabian Weiler, Uwe Marksteiner, Benjamin Witschas, Stephan Rahm, Alexander Geiß, and Oliver Reitebuch
Atmos. Meas. Tech., 13, 2075–2097, https://doi.org/10.5194/amt-13-2075-2020, 2020
This work reports on the first airborne validation campaign of ESA’s Earth Explorer mission Aeolus, conducted in central Europe during the commissioning phase in November 2018. After presenting the methodology used to compare the data sets from the satellite, the airborne wind lidar and the ECWMF model, the wind results from the underflights performed are analyzed and discussed, providing a first assessment of the accuracy and precision of the preliminary Aeolus wind data.
Implementation of an IBBCEAS technique in an atmospheric simulation chamber for in situ NO3 monitoring: characterization and validation for kinetic studies
Axel Fouqueau, Manuela Cirtog, Mathieu Cazaunau, Edouard Pangui, Pascal Zapf, Guillaume Siour, Xavier Landsheere, Guillaume Méjean, Daniele Romanini, and Bénédicte Picquet-Varrault
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2020-103,2020
Preprint under review for AMT (discussion: open, 0 comments)
An incoherent broadband cavity-enhanced absorption spectroscopy (IBBCEAS) technique has been developed for in situ monitoring of NO3 radicals in the CSA simulation chamber (at LISA). The optical cavity allows a high sensitivity for NO3 detection up to 6 ppt for an integration time of 10 seconds. The technique is now fully operational and can be used to determine rate constants for fast reactions involving complex volatile organic compounds (with rate constants up to 10-10 cm3 molecule-1 s-1).
Microwave single scattering properties of non-spheroidal rain drops
Robin Ekelund, Patrick Eriksson, and Michael Kahnert
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2020-85,2020
Preprint under review for AMT (discussion: open, 0 comments)
Rain drops become flattened due to aerodynamic drag, as they increase in mass and fall-speed. The shape of such rain drops was calculated, and the electromagnetic interaction between microwave radiation and the rain drops was calculated. The calculations are made publicly available to the scientific community, in order to promote accurate representations of rain drops in measurements. Tests show that the drop shape can indeed have a noticeable effect on microwave observations of heavy rainfall.
Uncertainty Quantification for Atmospheric Motion Vectors with Machine Learning
Joaquim V. Teixeira, Hai Nguyen, Derek J. Posselt, Hui Su, and Longtao Wu
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2020-95,2020
Preprint under review for AMT (discussion: open, 0 comments)
Wind-tracking algorithms produce atmospheric motion vectors (AMVs) by tracking satellite observations. Accurately characterizing the uncertainties in AMVs is essential in assimilating them into data assimilation models. We develop a machine learning based approach for error characterization which involves gaussian mixture model clustering and random forest using a simulation dataset of water vapor, AMVs, and true winds. We show that our method improves on existing AMV error characterizations.
