The Deep Convective Clouds and Chemistry (DC3) Field Campaign

Barth, M. C.; Cantrell, C. A.; Brune, William H.; Rutledge, Steven A.; Crawford, J. H.; Huntrieser, H.; Carey, Lawrence D.; MacGorman, Donald R.; Weisman, Morris L.; Pickering, Kenneth; Bruning, Eric C.; Anderson, B. E.; Apel, E. C.; Biggerstaff, Michael I.; Campos, T.; Campuzano‐Jost, P.; Cohen, R. C.; Crounse, J. D.; Day, Douglas A.; Diskin, G. S.; Flocke, Frank; Fried, Alan; Garland, C.; Heikes, Brian G.; Honomichl, Shawn; Hornbrook, R. S.; Huey, L. G.; Jimenez, José L.; Lang, Timothy J.; Lichtenstern, Michael; Mikoviny, Tomáš; Nault, Benjamin A.; O’Sullivan, Daniel W.; Pan, Laura L.; Peischl, J.; Pollack, I. B.; Richter, Dirk; Riemer, D. D.; Ryerson, Thomas B.; Schläger, Hans; Walega, J.; Weibring, Petter; Weinheimer, A. J.; Wennberg, P. O.; Wisthaler, Armin; Wooldridge, P. J.; Ziegler, Conrad L.

doi:10.1175/bams-d-13-00290.1

Cited by 194 publications

(258 citation statements)

References 74 publications

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“…Iyer et al (2016) reported a binding enthalpy of −70.5 kJ mol −1 for I − (HAc) and −106.8 kJ mol −1 for I − (HFo). The binding enthalpies are reported here as negative values, indicating an exothermic process and opposite to the NIST nomenclature for ion-molecule reactions (Bartmess, 2017). They correlated the sensitivities of Lee et al (2014) to binding energy and theorized the binding enthalpy for an analyte in an I − cluster could be used to predict its sensitivity.…”

Section: Resultsmentioning

confidence: 67%

Measurement of formic acid, acetic acid and hydroxyacetaldehyde, hydrogen peroxide, and methyl peroxide in air by chemical ionization mass spectrometry: airborne method development

et al. 2018

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Abstract. A chemical ionization mass spectrometry (CIMS) method utilizing a reagent gas mixture of O2, CO2, and CH3I in N2 is described and optimized for quantitative gas-phase measurements of hydrogen peroxide (H2O2), methyl peroxide (CH3OOH), formic acid (HCOOH), and the sum of acetic acid (CH3COOH) and hydroxyacetaldehyde (HOCH2CHO; also known as glycolaldehyde). The instrumentation and methodology were designed for airborne in situ field measurements. The CIMS quantification of formic acid, acetic acid, and hydroxyacetaldehyde used I− cluster formation to produce and detect the ion clusters I−(HCOOH), I−(CH3COOH), and I−(HOCH2CHO), respectively. The CIMS also produced and detected I− clusters with hydrogen peroxide and methyl peroxide, I−(H2O2) and I−(CH3OOH), though the sensitivity was lower than with the O2− (CO2) and O2− ion clusters, respectively. For that reason, while the I− peroxide clusters are presented, the focus is on the organic acids. Acetic acid and hydroxyacetaldehyde were found to yield equivalent CIMS responses. They are exact isobaric compounds and indistinguishable in the CIMS used. Consequently, their combined signal is referred to as the acetic acid equivalent sum. Within the resolution of the quadrupole used in the CIMS (1 m∕z), ethanol and 1- and 2-propanol were potential isobaric interferences to the measurement of formic acid and the acetic acid equivalent sum, respectively. The CIMS response to ethanol was 3.3 % that of formic acid and the response to either 1- or 2-propanol was 1 % of the acetic acid response; therefore, the alcohols were not considered to be significant interferences to formic acid or the acetic acid equivalent sum. The multi-reagent ion system was successfully deployed during the Front Range Air Pollution and Photochemistry Éxperiment (FRAPPÉ) in 2014. The combination of FRAPPÉ and laboratory calibrations allowed for the post-mission quantification of formic acid and the acetic acid equivalent sum observed during the Deep Convective Clouds and Chemistry Experiment in 2012.

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Section: Resultsmentioning

confidence: 67%

Measurement of formic acid, acetic acid and hydroxyacetaldehyde, hydrogen peroxide, and methyl peroxide in air by chemical ionization mass spectrometry: airborne method development

et al. 2018

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“…The first polarized imaging nephelometer used for field measurements employed a wide-angle lens and charge-coupled device (CCD) to record the scattering phase function under two orthogonal linear polarization conditions at three wavelengths (473, 532, and 671 nm) and derive both the phase function and degree of linear polarization across the visible spectral region (Dolgos and Martins, 2014;Espinosa et al, 2017). This instrument was deployed on the NASA DC8 aircraft for the Deep Convective Clouds and Chemistry (DC3) campaign in 2012 (Barth et al, 2015) and the Studies of Emissions and Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys (SEAC 4 RS) mission in 2014 (Toon et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

Investigating biomass burning aerosol morphology using a laser imaging nephelometer

et al. 2018

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Abstract. Particle morphology is an important parameter affecting aerosol optical properties that are relevant to climate and air quality, yet it is poorly constrained due to sparse in situ measurements. Biomass burning is a large source of aerosol that generates particles with different morphologies. Quantifying the optical contributions of non-spherical aerosol populations is critical for accurate radiative transfer models, and for correctly interpreting remote sensing data. We deployed a laser imaging nephelometer at the Missoula Fire Sciences Laboratory to sample biomass burning aerosol from controlled fires during the FIREX intensive laboratory study. The laser imaging nephelometer measures the unpolarized scattering phase function of an aerosol ensemble using diode lasers at 375 and 405 nm. Scattered light from the bulk aerosol in the instrument is imaged onto a chargecoupled device (CCD) using a wide-angle field-of-view lens, which allows for measurements at 4-175 • scattering angle with ∼ 0.5 • angular resolution. Along with a suite of other instruments, the laser imaging nephelometer sampled fresh smoke emissions both directly and after removal of volatile components with a thermodenuder at 250 • C. The total integrated aerosol scattering signal agreed with both a cavity ring-down photoacoustic spectrometer system and a traditional integrating nephelometer within instrumental uncertainties. We compare the measured scattering phase functions at 405 nm to theoretical models for spherical (Mie) and fractal (Rayleigh-Debye-Gans) particle morphologies based on the size distribution reported by an optical particle counter.Results from representative fires demonstrate that particle morphology can vary dramatically for different fuel types. In some cases, the measured phase function cannot be described using Mie theory. This study demonstrates the capabilities of the laser imaging nephelometer instrument to provide realtime, in situ information about dominant particle morphology, which is vital for understanding remote sensing data and accurately describing the aerosol population in radiative transfer calculations.

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“…In this paper, we report on observations of frozen-drop aggregates and frozen-drop chain aggregates made in the upper regions of several midlatitude thunderstorm anvils over the continental United States (US) during the Deep Convective Clouds and Chemistry (DC3; Barth et al, 2012) experiment. Our results suggest that these types of aggregates are common in the upper levels of these storms and, together with individual frozen droplets, can dominate the particle types in the upper anvil.…”

Section: Introductionmentioning

confidence: 99%

Ice particles in the upper anvil regions of midlatitude continental thunderstorms: the case for frozen-drop aggregates

et al. 2014

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Abstract. This study examines the occurrence and morphology of frozen-drop aggregates in thunderstorm anvils from the United States Midwest and describes the environmental conditions where they are found. In situ airborne data collected in anvils using several particle imaging and sizing probes and bulk total water instrumentation during the 2012 Deep Convective Clouds and Chemistry experiment are examined for the presence of frozen-drop aggregates. Chains of frozen drops have been only rarely reported before and are hypothesized to aggregate due to electrical forces in the clouds. They were identified in nine of the anvil cases examined to date, suggesting that they are common features in these Midwestern anvils. High concentrations of individual frozen droplets occurred on the tops and edges of one particular set of anvils, while regions closer to the center and bottom of these anvils exhibited fewer frozen drops and more frozen-drop aggregates. Bulk ice water content measurements across these anvils could only be explained by contributions from both small particles (frozen droplets) and large particles (large aggregates of frozen droplets). Dual Doppler radar analysis confirmed the presence of deep and strong (> 15 m s −1 ) updrafts in the parent cloud of one of the anvils. These features contrast with previous anvil measurements in tropical/maritime anvils that evidently do not exhibit the same frequency of frozen-drop aggregates.

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The Deep Convective Clouds and Chemistry (DC3) Field Campaign

Abstract: DC3 brought together simultaneous measurements of storm kinematics, structure, electrical activity, and chemistry to improve our knowledge of how thunderstorms affect the chemical composition of the troposphere.

Cited by 194 publications

References 74 publications

Measurement of formic acid, acetic acid and hydroxyacetaldehyde, hydrogen peroxide, and methyl peroxide in air by chemical ionization mass spectrometry: airborne method development

Measurement of formic acid, acetic acid and hydroxyacetaldehyde, hydrogen peroxide, and methyl peroxide in air by chemical ionization mass spectrometry: airborne method development

Investigating biomass burning aerosol morphology using a laser imaging nephelometer

Ice particles in the upper anvil regions of midlatitude continental thunderstorms: the case for frozen-drop aggregates

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