Technical note: Determination of binary gas-phase diffusion coefficients of unstable and adsorbing atmospheric trace gases at low temperature – arrested flow and twin tube method

Langenberg, Stefan; Carstens, Torsten; Hupperich, Dirk; Schweighoefer, Silke; Schurath, U.

doi:10.5194/acp-20-3669-2020

Cited by 22 publications

(13 citation statements)

References 43 publications

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“…Literature measurements: symbols as listed below, bath gas, authors, and year are indicated parenthetically. CH 4 : plus symbols (air, Coward and Georgeson, 1937); x symbols (N 2 , Wakeham and Slater, 1973); Y symbols (N 2 , Engel and Knapp, 1973); fully-filled hexagons (N 2 , Mueller and Cahill, 1964); bottom-filled hexagon (N 2 , review, Massman, 1998); left-filled hexagons (air, Langenberg et al , 2020); right-filled hexagon (air, Cowie and Watts, 1971) (obstructed by solid hexagon at 298 K); top-filled hexagons (air, 1961). CH 2 F 2 : filled circles (air, Matsunaga et al , 2002).…”

Section: Resultsmentioning

confidence: 99%

Binary Diffusion Coefficients for Methane and Fluoromethanes in Nitrogen

McGivern

Manion

2021

J. Chem. Eng. Data

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Binary gas-phase diffusion coefficients, of interest in physical models of atmospheric and combustion chemistry, have been measured in N2 for the homologous series of refrigerant-related (fluoro)methanes: methane (CH4), fluoromethane (CH3F), difluoromethane (CH2F2), and trifluoromethane (CHF3). Values have been determined by reverse-flow gas chromatography, which has been previously demonstrated to provide accurate results over a wide range of temperatures. Coefficients were measured at temperatures of (300–550) K for all species and extending up to 650 and 723 K for CH2F2 and CHF3, respectively, and down to 250 K for CH4. We also performed measurements for CH4 in air at temperatures of (250–350) K, obtaining values the same as in N2 within 0.3%, well within our experimental uncertainty. We report the first measurements for CH3F and compare with the limited literature data for the other compounds. Our results agree broadly with earlier measurements in both N2 and air. The greater temperature ranges reported in this work lead to temperature dependences that differ from most previous experiments, although they are consistent with several literature estimates and are similar to temperature exponents found for small hydrocarbons in N2. Comparison of the present work with a recent study that found different diffusion coefficients for methane when determined in a typical arrested flow apparatus and a novel “twin tube” method unaffected by sample adsorption shows a much better agreement with the arrested flow results over all common temperatures.

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Section: Resultsmentioning

confidence: 99%

Binary Diffusion Coefficients for Methane and Fluoromethanes in Nitrogen

McGivern

Manion

2021

J. Chem. Eng. Data

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“…Because the O 3 was added through a side port of the tube, a mixing time of 1.5 ms was applied in the model. This was estimated as the time taken for O 3 to diffuse 1 cm across the tube with D (O 3 ‐N 2 = 134 cm 2 s −1 ) at 1 Torr (Langenberg et al, 2020). The model fit through the experimental points yields k 6 (294 K) = (2.5 ± 1.2) × 10 −11 cm −3 molecule s −1 .…”

Section: Underpinning Laboratory and Theoretical Workmentioning

confidence: 99%

The Meteoric Ni Layer in the Upper Atmosphere

et al. 2020

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The first global atmospheric model of Ni (WACCM‐Ni) has been developed to understand recent observations of the mesospheric Ni layer by ground‐based resonance lidars. The three components of the model are: the Whole Atmospheric Community Climate Model (WACCM6); a meteoric input function derived by coupling an astronomical model of dust sources in the solar system with a chemical meteoric ablation model; and a comprehensive set of neutral, ion‐molecule, and photochemical reactions pertinent to the chemistry of Ni in the upper atmosphere. In order to achieve closure on the chemistry, the reaction kinetics of three important reactions were first studied using a fast flow tube with pulsed laser ablation of a Ni target, yielding k(NiO + O) = (4.6 ± 1.4) × 10−11, k(NiO + CO) = (3.0 ± 0.5) × 10−11, and k(NiO2 + O) = (2.5 ± 1.2) × 10−11 cm3 molecule−1 s−1 at 294 K. The photodissociation rate of NiOH was computed to be J(NiOH) = 0.02 s−1. WACCM‐Ni simulates satisfactorily the observed neutral Ni layer peak height and width, and Ni+ measurements from rocket‐borne mass spectrometry. The Ni layer is predicted to have a similar seasonal and latitudinal variation as the Fe layer, and its unusually broad bottom‐side compared with Fe is caused by the relatively fast NiO + CO reaction. The quantum yield for photon emission from the Ni + O3 reaction, observed in the nightglow, is estimated to be between 6% and 40%.

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“…This factor is recommended by the guideline from the International Cooperative Programme on Effects of Air Pollution on Natural Vegetation and Crops (ICP Vegetation) [18]. Recently, the ozone molecular diffusivities to air were experimentally measured for the first time [42], and the uncertainty of this quantity was reduced substantially. The conversion factor should be updated in the future according to the results [42] to the value of 0.704 with 8% uncertainty.…”

Section: Field Measurements Of Stomatal Conductancementioning

confidence: 99%

“…Recently, the ozone molecular diffusivities to air were experimentally measured for the first time [42], and the uncertainty of this quantity was reduced substantially. The conversion factor should be updated in the future according to the results [42] to the value of 0.704 with 8% uncertainty. This new factor is in accordance with the currently used recommended value within the uncertainties.…”

Section: Field Measurements Of Stomatal Conductancementioning

confidence: 99%

Specification of Modified Jarvis Model Parameterization for Pinus cembra

et al. 2021

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The high ambient ozone concentrations cause impairing effects on vegetation leading to plant injuries. The potential ozone uptake to vegetation through open stomata can be quantified using stomatal conductance measurements under the local environmental conditions. This study compares the ozone stomatal conductance to vegetation obtained with a modified Jarvis formula adopted from the Vegetation Manual of United Nations Economic Commission for Europe, and experimental field measurements’ data. The stomatal conductance was measured by a portable photosynthesis and gas exchange analyzer system LiCOR6400. The measurements were performed in the submontane environment of the High Tatra Mountains in Slovakia on Swiss pine (Pinus cembra), as a native species of the local flora. According to previous studies, Swiss pine is considered as an ozone-sensitive species. The modified Jarvis model for the ozone stomatal conductance is compared with the field measurements. The suitable parameterization of the modified Jarvis model for Swiss pine is obtained. The parameterization of stomatal conductance for Swiss pine in the local environment would help understand its specificity and similarity to other conifer species. In the case of using parameterization for a boreal coniferous from the Vegetation Manual of the International Cooperative Programme on Effects of Air Pollution on Natural Vegetation and Crops, validation of the model with the measurements without temperature adjustment of the conifer chamber achieved a coefficient of determination of R2=0.75. This result is not in contradiction with the previous researches. With the optimal set of parameters, obtained in this paper, the Jarvis model reaches R2=0.85. The data suggest that Jarvis-type models with appropriate parameterization are applicable for stomatal conductance estimation for Pinus cembra when the measurements do not modify the temperature regime.

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Technical note: Determination of binary gas-phase diffusion coefficients of unstable and adsorbing atmospheric trace gases at low temperature – arrested flow and twin tube method

Cited by 22 publications

References 43 publications

Binary Diffusion Coefficients for Methane and Fluoromethanes in Nitrogen

Binary Diffusion Coefficients for Methane and Fluoromethanes in Nitrogen

The Meteoric Ni Layer in the Upper Atmosphere

Specification of Modified Jarvis Model Parameterization for Pinus cembra

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