62 results match your criteria Atmospheric Measurement Techniques[Journal]

Development and Application of a United States wide correction for PM data collected with the PurpleAir sensor.

Atmos Meas Tech 2021 Jun;4(6)

Office of Research and Development, U.S. Environmental Protection Agency 109 T.W. Alexander Drive Research Triangle Park, NC 27711.

PurpleAir sensors, which measure particulate matter (PM), are widely used by individuals, community groups, and other organizations including state and local air monitoring agencies. PurpleAir sensors comprise a massive global network of more than 10,000 sensors. Previous performance evaluations have typically studied a limited number of PurpleAir sensors in small geographic areas or laboratory environments. Read More

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Use of an unmanned aircraft system to quantify NO emissions from a natural gas boiler.

Atmos Meas Tech 2021 Feb;14(2):975-981

The Dow Chemical Company, Midland, Michigan 48667, USA.

Aerial emission sampling of four natural gas boiler stack plumes was conducted using an unmanned aerial system (UAS) equipped with a lightweight sensor-sampling system (the "Kolibri") for measurement of nitrogen oxide (NO), and nitrogen dioxide (NO), carbon dioxide (CO), and carbon monoxide (CO). Flights (=22) ranged from 11 to 24min in duration at two different sites. The UAS was maneuvered into the plumes with the aid of real-time CO telemetry to the ground operators and, at one location, a second UAS equipped with an infrared-visible camera. Read More

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February 2021

Evaluating Sentinel-5P TROPOMI tropospheric NO column densities with airborne and Pandora spectrometers near New York City and Long Island Sound.

Atmos Meas Tech 2020 Nov;13(11):6113-6140

Office of Research and Development, United States Environmental Protection Agency, Triangle Research Park, NC 27709, USA.

Airborne and ground-based Pandora spectrometer NO column measurements were collected during the 2018 Long Island Sound Tropospheric Ozone Study (LISTOS) in the New York City/Long Island Sound region, which coincided with early observations from the Sentinel-5P TROPOspheric Monitoring Instrument (TROPOMI) instrument. Both airborne- and ground-based measurements are used to evaluate the TROPOMI NO Tropospheric Vertical Column (TrVC) product v1.2 in this region, which has high spatial and temporal heterogeneity in NO. Read More

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November 2020

Comparison of ozone measurement methods in biomass burning smoke: an evaluation under field and laboratory conditions.

Atmos Meas Tech 2021 Mar;14(3):1783-1800

Center for Environmental Measurement and Modeling, Office of Research and Development, United States Environmental Protection Agency, Research Triangle Park, North Carolina, United States of America.

In recent years wildland fires in the United States have had significant impacts on local and regional air quality and negative human health outcomes. Although the primary health concerns from wildland fires come from fine particulate matter (PM), large increases in ozone (O) have been observed downwind of wildland fire plumes (DeBell et al., 2004; Bytnerowicz et al. Read More

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Effect of Polyoxymethylene (POM-H Delrin) offgassing within Pandora head sensor on direct sun and multi-axis formaldehyde column measurements in 2016 - 2019.

Atmos Meas Tech 2021 ;14(1):647-663

NASA Goddard Space Flight Center, Greenbelt, MD, USA.

Analysis of formaldehyde measurements by the Pandora spectrometer systems between 2016 and 2019 suggested that there was a temperature dependent process inside Pandora head sensor that emitted formaldehyde. Some parts in the head sensor were manufactured from thermal plastic polyoxymethylene homopolimer (E.I. Read More

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January 2021

Stationary and portable multipollutant monitors for high-spatiotemporal-resolution air quality studies including online calibration.

Atmos Meas Tech 2021 Feb 9;14(2):995-1013. Epub 2021 Feb 9.

Department of Chemical & Environmental Engineering, Yale University, School of Engineering and Applied Science, New Haven, Connecticut 06511, USA.

The distribution and dynamics of atmospheric pollutants are spatiotemporally heterogeneous due to variability in emissions, transport, chemistry, and deposition. To understand these processes at high spatiotemporal resolution and their implications for air quality and personal exposure, we present custom, low-cost air quality monitors that measure concentrations of contaminants relevant to human health and climate, including gases (e.g. Read More

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February 2021

Gradient boosting machine learning to improve satellite-derived column water vapor measurement error.

Atmos Meas Tech 2020 2;13(9):4669-4681. Epub 2020 Sep 2.

Department of Geography and Environmental Development, Ben-Gurion University of the Negev, Beersheba, Israel.

The atmospheric products of the Multi-Angle Implementation of Atmospheric Correction (MAIAC) algorithm include column water vapor (CWV) at a 1 km resolution, derived from daily overpasses of NASA's Moderate Resolution Imaging Spectroradiometer (MODIS) instruments aboard the Aqua and Terra satellites. We have recently shown that machine learning using extreme gradient boosting (XGBoost) can improve the estimation of MAIAC aerosol optical depth (AOD). Although MAIAC CWV is generally well validated (Pearson's >0. Read More

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September 2020

Evaluating the impact of spatial resolution on tropospheric NO column comparisons within urban areas using high-resolution airborne data.

Atmos Meas Tech 2019 Nov 22;12(11):6091-6111. Epub 2019 Nov 22.

United States Environmental Protection Agency Office of Research and Development, Triangle Research Park, NC, 27709, United States.

NASA deployed the GeoTASO airborne UV-Visible spectrometer in May-June 2017 to produce high resolution (approximately 250 × 250 m) gapless NO datasets over the western shore of Lake Michigan and over the Los Angeles Basin. The results collected show that the airborne tropospheric vertical column retrievals compare well with ground-based Pandora spectrometer column NO observations (r=0.91 and slope of 1. Read More

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November 2019

Assessment of NO observations during DISCOVER-AQ and KORUS-AQ field campaigns.

Atmos Meas Tech 2020 May;13(5)

NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA.

NASA's Deriving Information on Surface Conditions from Column and Vertically Resolved Observations Relevant to Air Quality (DISCOVER-AQ, conducted in 2011-2014) campaign in the United States and the joint NASA and National Institute of Environmental Research (NIER) Korea-United States Air Quality Study (KORUS-AQ, conducted in 2016) in South Korea were two field study programs that provided comprehensive, integrated datasets of airborne and surface observations of atmospheric constituents, including nitrogen dioxide (NO), with the goal of improving the interpretation of spaceborne remote sensing data. Various types of NO measurements were made, including in situ concentrations and column amounts of NO using ground- and aircraft-based instruments, while NO column amounts were being derived from the Ozone Monitoring Instrument (OMI) on the Aura satellite. This study takes advantage of these unique datasets by first evaluating in situ data taken from two different instruments on the same aircraft platform, comparing coincidently sampled profile-integrated columns from aircraft spirals with remotely sensed column observations from ground-based Pandora spectrometers, intercomparing column observations from the ground (Pandora), aircraft (in situ vertical spirals), and space (OMI), and evaluating NO simulations from coarse Global Modeling Initiative (GMI) and high-resolution regional models. Read More

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A new laser-based and ultra-portable gas sensor for indoor and outdoor formaldehyde (HCHO) monitoring.

Atmos Meas Tech 2019 Nov 22;12(11):6079-6089. Epub 2019 Nov 22.

Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA.

In this work, a new commercially available, laser-based, and ultra-portable formaldehyde (HCHO) gas sensor is characterized, and its usefulness for monitoring HCHO mixing ratios in both indoor and outdoor environments is assessed. Stepped calibrations and intercomparison with well-established laser-induced fluorescence (LIF) instrumentation allow a performance evaluation of the absorption-based, mid-infrared HCHO sensor from Aeris Technologies, Inc. The Aeris sensor displays linear behavior (R > 0. Read More

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November 2019

Cloud Products from the Earth Polychromatic Imaging Camera (EPIC): Algorithms and Initial Evaluation.

Atmos Meas Tech 2019 29;12(3):2019-2031. Epub 2019 Mar 29.

NASA Langley Research Center, Hampton, VA.

This paper presents the physical basis of the EPIC cloud product algorithms and an initial evaluation of their performance. Since June 2015, EPIC has been providing observations of the sunlit side of the Earth with its 10 spectral channels ranging from the UV to the near-IR. A suite of algorithms has been developed to generate the standard EPIC Level 2 Cloud Products that include cloud mask, cloud effective pressure/height, and cloud optical thickness. Read More

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Mobile-Platform Measurement of Air Pollutant Concentrations in California: Performance Assessment, Statistical Methods for Evaluating Spatial Variations, and Spatial Representativeness.

Atmos Meas Tech 2020 ;13(6)

Electric Power Research Institute, 3420 Hillview Ave, Palo Alto, CA, 94304, USA.

Mobile platform measurements provide new opportunities for characterizing spatial variations of air pollution within urban areas, identifying emission sources, and enhancing knowledge of atmospheric processes. The Aclima, Inc. mobile measurement and data acquisition platform was used to equip four Google Street View cars with research-grade instruments, two of which were available for the duration of this study. Read More

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January 2020

Assessing the accuracy of low-cost optical particle sensors using a physics-based approach.

Atmos Meas Tech 2020 26;13(11):6343-6355. Epub 2020 Nov 26.

Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.

Low-cost sensors for measuring particulate matter (PM) offer the ability to understand human exposure to air pollution at spatiotemporal scales that have previously been impractical. However, such low-cost PM sensors tend to be poorly characterized, and their measurements of mass concentration can be subject to considerable error. Recent studies have investigated how individual factors can contribute to this error, but these studies are largely based on empirical comparisons and generally do not examine the role of multiple factors simultaneously. Read More

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November 2020

Cloud Aerosol Transport System (CATS) 1064 nm Calibration and Validation.

Atmos Meas Tech 2019 Nov;12(11):6241-6258

National Observatory of Athens, Institute for Astronomy, Astrophysics, Space Application and Remote Sensing, Athens, Greece.

The Cloud-Aerosol Transport System (CATS) lidar on board the International Space Station (ISS) operated from 10 February 2015 to 30 October 2017 providing range-resolved vertical backscatter profiles of Earth's atmosphere at 1064 and 532 nm. The CATS instrument design and ISS orbit lead to a higher 1064 nm signal-to-noise ratio than previous space-based lidars, allowing for direct atmospheric calibration of the 1064 nm signals. Nighttime CATS Version 3-00 data were calibrated by scaling the measured data to a model of the expected atmospheric backscatter between 22 and 26 km above mean sea level (AMSL). Read More

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November 2019

Using a Speed-Dependent Voigt Line Shape to Retrieve O from Total Carbon Column Observing Network Solar Spectra to Improve Measurements of XCO.

Atmos Meas Tech 2019 ;12

Harvard John A. Paulson School of Engineering and Applied Sciences, Cambridge, MA, USA.

High-resolution, laboratory, absorption spectra of the oxygen (O) band measured using cavity ring-down spectroscopy were fitted using the Voigt and speed-dependent Voigt line shapes. We found that the speed-dependent Voigt line shape was better able to model the measured absorption coefficients than the Voigt line shape. We used these line shape models to calculate absorption coefficients to retrieve atmospheric total columns abundances of O from ground-based spectra from four Fourier transform spectrometers that are apart of the Total Carbon Column Observing Network (TCCON) Lower O total columns were retrieved with the speed-dependent Voigt line shape, and the difference between the total columns retrieved using the Voigt and speed-dependent Voigt line shapes increased as a function of solar zenith angle. Read More

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January 2019

Characterising low-cost sensors in highly portable platforms to quantify personal exposure in diverse environments.

Atmos Meas Tech 2019 30;12(8):4643-4657. Epub 2019 Aug 30.

Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK.

The inaccurate quantification of personal exposure to air pollution introduces error and bias in health estimations, severely limiting causal inference in epidemiological research worldwide. Rapid advancements in affordable, miniaturised air pollution sensor technologies offer the potential to address this limitation by capturing the high variability of personal exposure during daily life in large-scale studies with unprecedented spatial and temporal resolution. However, concerns remain regarding the suitability of novel sensing technologies for scientific and policy purposes. Read More

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Using collision-induced dissociation to constrain sensitivity of ammonia chemical ionization mass spectrometry ( CIMS) to oxygenated volatile organic compounds.

Atmos Meas Tech 2019 20;12(3):1861-1870. Epub 2019 Mar 20.

John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA.

Chemical ionization mass spectrometry (CIMS) instruments routinely detect hundreds of oxidized organic compounds in the atmosphere. A major limitation of these instruments is the uncertainty in their sensitivity to many of the detected ions. We describe the development of a new high-resolution time-of-flight chemical ionization mass spectrometer that operates in one of two ionization modes: using either ammonium ion ligand-switching reactions such as for CIMS or proton transfer reactions such as for protontransfer-reaction mass spectrometer (PTR-MS). Read More

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Improvement of stratospheric aerosol extinction retrieval from OMPS/LP using a new aerosol model.

Atmos Meas Tech 2018 Dec 6;11(12):6495-6509. Epub 2018 Dec 6.

Science Systems and Applications, Inc., Lanham, Maryland, 20706, USA.

The Ozone Mapping and Profiler Suite Limb Profiler (OMPS/LP) has been flying on the Suomi NPP satellite since October 2011. It is designed to produce ozone and aerosol vertical profiles at ~2 km vertical resolution over the entire sunlit globe. Aerosol extinction profiles are computed with Mie theory using radiances measured at 675 nm. Read More

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December 2018

Assessing snow extent data sets over North America to inform and improve trace gas retrievals from solar backscatter.

Atmos Meas Tech 2018 22;11(5):2983-2994. Epub 2018 May 22.

Air Quality Research Division, Environment and Climate Change Canada, Toronto, Ontario, Canada.

Accurate representation of surface reflectivity is essential to tropospheric trace gas retrievals from solar backscatter observations. Surface snow cover presents a significant challenge due to its variability and thus snow-covered scenes are often omitted from retrieval data sets; however, the high reflectance of snow is potentially advantageous for trace gas retrievals. We first examine the implications of surface snow on retrievals from the upcoming TEMPO geostationary instrument for North America. Read More

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Chromatography related performance of the Monitor for AeRosols and GAses in ambient air (MARGA): laboratory and field-based evaluation.

Atmos Meas Tech 2017 Oct;10(10):3893-3908

National Risk Management Research Laboratory, Office of Research and Development, US Environmental Protection Agency, Research Triangle Park, North Carolina, 27711, USA.

Evaluation of the semi-continuous Monitor for AeRosols and GAses in ambient air (MARGA, Metrohm Ap-plikon B.V.) was conducted with an emphasis on examination of accuracy and precision associated with processing of chromatograms. Read More

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October 2017

Development and characterization of a high-efficiency, aircraft-based axial cyclone cloud water collector.

Atmos Meas Tech 2018 Aug 5;11(9):5025-5048. Epub 2018 Sep 5.

NASA Langley Research Center, Hampton, VA 23666, USA.

A new aircraft-mounted probe for collecting samples of cloud water has been designed, fabricated, and extensively tested. Following previous designs, the probe uses inertial separation to remove cloud droplets from the airstream, which are subsequently collected and stored for offline analysis. We report details of the design, operation, and modelled and measured probe performance. Read More

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CALIPSO lidar level 3 aerosol profile product: version 3 algorithm design.

Atmos Meas Tech 2018 Jul 17;11(7):4129-4152. Epub 2018 Jul 17.

Science Systems and Applications, Inc., Hampton, VA, USA.

The CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations) level 3 aerosol profile product reports globally gridded, quality-screened, monthly mean aerosol extinction profiles retrieved by CALIOP (the Cloud-Aerosol Lidar with Orthogonal Polarization). This paper describes the quality screening and averaging methods used to generate the version 3 product. The fundamental input data are CALIOP level 2 aerosol extinction profiles and layer classification information (aerosol, cloud, and clear-air). Read More

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Remote sensing of aerosols with small satellites in formation flight.

Atmos Meas Tech 2018 Jul 6;11(7):3935-3954. Epub 2018 Jul 6.

Bay Area Environmental Research Institute, Petaluma, CA, USA.

Determination of aerosol optical properties with orbital passive remote sensing is a difficult task, as observations often have limited information. Multi-angle instruments, such as the Multi-angle Imaging SpectroRadiometer (MISR) and the POlarization and Directionality of the Earth's Reflectances (POLDER), seek to address this by making information rich multi-angle observations, which can be used to better retrieve aerosol optical properties. The paradigm for such instruments is that each angle view is made from one platform, with, for example, a gimbaled sensor or multiple fixed view angle sensors. Read More

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Exploring systematic offsets between aerosol products from the two MODIS sensors.

Atmos Meas Tech 2018 Jul 13;11(7):4073-4092. Epub 2018 Jul 13.

University of Maryland-Baltimore County (UMBC), Baltimore, Maryland, USA.

Long-term measurements of global aerosol loading and optical properties are essential for assessing climate-related questions. Using observations of spectral reflectance and radiance, the dark-target (DT) aerosol retrieval algorithm is applied to Moderate-resolution Imaging Spectroradiometer sensors on both Terra (MODIS-T) and Aqua (MODIS-A) satellites, deriving products (known as MOD04 and MYD04, respectively) of global aerosol optical depth (AOD at 0.55 μm) over both land and ocean, and Angstrom Exponent (AE derived from 0. Read More

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Laser pulse bidirectional reflectance from CALIPSO mission.

Atmos Meas Tech 2018 Jun 8;11(6):3281-3296. Epub 2018 Jun 8.

NASA Langley Research Center, Hampton, VA, 23681, USA.

This paper presents an innovative retrieval method that translate the CALIOP land surface laser pulse returns into the surface bidirectional reflectance. To better analyze the surface returns, the CALIOP receiver impulse response and the downlinked samples' distribution at 30 m resolution are discussed. The saturated laser pulse returns from snow and ice surfaces are recovered based on surface tail information. Read More

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Assessing a low-cost methane sensor quantification system for use in complex rural and urban environments.

Atmos Meas Tech 2018 Jun 20;11(6):3569-3594. Epub 2018 Jun 20.

Department of Mechanical Engineering, University of Colorado Boulder, Boulder, CO, 80309, USA.

Low-cost sensors have the potential to facilitate the exploration of air quality issues on new temporal and spatial scales. Here we evaluate a low-cost sensor quantification system for methane through its use in two different deployments. The first was a one-month deployment along the Colorado Front Range and included sites near active oil and gas operations in the Denver-Julesberg basin. Read More

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CALIPSO IIR Version 2 Level 1b calibrated radiances: analysis and reduction of residual biases in the Northern Hemisphere.

Atmos Meas Tech 2018 Apr;11(4):2485-2500

Laboratoire de Météorologie Dynamique, Ecole Polytechnique-CNRS, Palaiseau, 91128, France.

Version 2 of the Level 1b calibrated radiances of the Imaging Infrared Radiometer (IIR) on board the Cloud-Aerosol Lidar and Infrared Satellite Observation (CALIPSO) satellite has been released recently. This new version incorporates corrections of small but systematic seasonal calibration biases previously revealed in Version 1 data products mostly north of 30° N. These biases of different amplitudes in the three IIR channels 8. Read More

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Characterization of smoke and dust episode over West Africa: comparison of MERRA-2 modeling with multiwavelength Mie-Raman lidar observations.

Atmos Meas Tech 2018 Mar 16;11(2):949-969. Epub 2018 Feb 16.

Physics Instrumentation Center of GPI, Troitsk, Moscow, Russia.

Observations of multiwavelength Mie-Raman lidar taken during the SHADOW field campaign are used to analyze a smoke-dust episode over West Africa on 24-27 December 2015. For the case considered, the dust layer extended from the ground up to approximately 2000 m while the elevated smoke layer occurred in the 2500-4000 m range. The profiles of lidar measured backscattering, extinction coefficients, and depolarization ratios are compared with the vertical distribution of aerosol parameters provided by the Modern-Era Retrospective Analysis for Research and Applications, version 2 (MERRA-2). Read More

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CALIPSO Lidar Calibration at 532 nm: Version 4 Nighttime Algorithm.

Atmos Meas Tech 2018 Mar 14;11(3):1459-1479. Epub 2018 Mar 14.

Science Systems and Applications Inc., Hampton, VA, USA.

Data products from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) on board Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) were recently updated following the implementation of new (version 4) calibration algorithms for all of the level 1 attenuated backscatter measurements. In this work we present the motivation for and the implementation of the version 4 nighttime 532 nm parallel channel calibration. The nighttime 532 nm calibration is the most fundamental calibration of CALIOP data, since all of CALIOP's other radiometric calibration procedures - i. Read More

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A Prototype Method for Diagnosing High Ice Water Content Probability Using Satellite Imager Data.

Atmos Meas Tech 2018 Mar;11(3):1615-1637

Laboratoire Atmosphere, Milieux, et Observations Spatiales, Guyancourt, France.

Recent studies have found that flight through deep convective storms and ingestion of high mass concentrations of ice crystals, also known as high ice water content (HIWC), into aircraft engines can adversely impact aircraft engine performance. These aircraft engine icing events caused by HIWC have been documented during flight in weak reflectivity regions near convective updraft regions that do not appear threatening in onboard weather radar data. Three airborne field campaigns were conducted in 2014 and 2015 to better understand how HIWC is distributed in deep convection, both as a function of altitude and proximity to convective updraft regions, and to facilitate development of new methods for detecting HIWC conditions, in addition to many other research and regulatory goals. Read More

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