Organics in environmental ices: sources, chemistry, and impacts

McNeill, V. Faye; Grannas, A. M.; Abbatt, Jonathan P. D.; Ammann, Markus; Ariya, Parisa A.; Bartels-Rausch, Thorsten; Dominé, Florent; Donaldson, D. J.; Guzmán, Marcelo I.; Heger, Dominik; Kahan, Tara F.; Klán, Petr; Masclin, S.; Toubin, Céline; Voisin, Didier

doi:10.5194/acp-12-9653-2012

Cited by 123 publications

(157 citation statements)

References 235 publications

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“…The onset and thickness of the DI not only depend on temperature, but also on the speciation and concentration of impurities present within the snow grain (McNeill et al, 2012;Dash et al, 2006). Different impurities have different impacts on the hydrogen bonding network at the ice surface and hence have a different impact on the thickness of the DI, leading in general to a thickening compared to pure ice (Bartels-Rausch et al, 2014).…”

Section: Disordered Interface -Model 1 (T > T O = 238 K)mentioning

confidence: 99%

Modelling the physical multiphase interactions of HNO3 between snow and air on the Antarctic Plateau (Dome C) and coast (Halley)

2018

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Abstract. Emissions of nitrogen oxide (NO x = NO + NO 2 ) from the photolysis of nitrate (NO − 3 ) in snow affect the oxidising capacity of the lower troposphere especially in remote regions of high latitudes with little pollution. Current air-snow exchange models are limited by poor understanding of processes and often require unphysical tuning parameters. Here, two multiphase models were developed from physically based parameterisations to describe the interaction of nitrate between the surface layer of the snowpack and the overlying atmosphere. The first model is similar to previous approaches and assumes that below a threshold temperature, T o , the air-snow grain interface is pure ice and above T o a disordered interface (DI) emerges covering the entire grain surface. The second model assumes that air-ice interactions dominate over all temperatures below melting of ice and that any liquid present above the eutectic temperature is concentrated in micropockets. The models are used to predict the nitrate in surface snow constrained by year-round observations of mixing ratios of nitric acid in air at a cold site on the Antarctic Plateau (Dome C; 75 • 06 S, 123 • 33 E; 3233 m a.s.l.) and at a relatively warm site on the Antarctic coast (Halley; 75 • 35 S, 26 • 39 E; 35 m a.s.l). The first model agrees reasonably well with observations at Dome C (C v (RMSE) = 1.34) but performs poorly at Halley (C v (RMSE) = 89.28) while the second model reproduces with good agreement observations at both sites (C v (RMSE) = 0.84 at both sites). It is therefore suggested that in winter air-snow interactions of nitrate are determined by non-equilibrium surface adsorption and cocondensation on ice coupled with solid-state diffusion inside the grain, similar to Bock et al. (2016). In summer, however, the air-snow exchange of nitrate is mainly driven by solvation into liquid micropockets following Henry's law with contributions to total surface snow NO − 3 concentrations of 75 and 80 % at Dome C and Halley, respectively. It is also found that the liquid volume of the snow grain and airmicropocket partitioning of HNO 3 are sensitive to both the total solute concentration of mineral ions within the snow and pH of the snow. The second model provides an alternative method to predict nitrate concentration in the surface snow layer which is applicable over the entire range of environmental conditions typical for Antarctica and forms a basis for a future full 1-D snowpack model as well as parameterisations in regional or global atmospheric chemistry models.

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Section: Disordered Interface -Model 1 (T > T O = 238 K)mentioning

confidence: 99%

Modelling the physical multiphase interactions of HNO3 between snow and air on the Antarctic Plateau (Dome C) and coast (Halley)

2018

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“…In the presence of oxygen, formation of the OH radical may create a radical-initiated oxidising medium allowing oxidation of organic chemicals to emit species such as formaldehyde, acetaldehyde or organic halogens to the lower atmosphere (McNeill et al, 2012). Another source of OH radicals in the snowpack is photolysis of hydrogen peroxide (H 2 O 2 ) Anastasio, 2005, 2007):…”

Section: (Z λ)mentioning

confidence: 99%

The impact of parameterising light penetration into snow on the photochemical production of NOx and OH radicals in snow

2015

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Abstract. Snow photochemical processes drive production of chemical trace gases in snowpacks, including nitrogen oxides (NO x = NO + NO 2 ) and hydrogen oxide radical (HO x = OH + HO 2 ), which are then released to the lower atmosphere. Coupled atmosphere-snow modelling of theses processes on global scales requires simple parameterisations of actinic flux in snow to reduce computational cost. The disagreement between a physical radiative-transfer (RT) method and a parameterisation based upon the e-folding depth of actinic flux in snow is evaluated. In particular, the photolysis of the nitrate anion (NO − 3 ), the nitrite anion (NO − 2 ) and hydrogen peroxide (H 2 O 2 ) in snow and nitrogen dioxide (NO 2 ) in the snowpack interstitial air are considered.The emission flux from the snowpack is estimated as the product of the depth-integrated photolysis rate coefficient, v, and the concentration of photolysis precursors in the snow. The depth-integrated photolysis rate coefficient is calculated (a) explicitly with an RT model (TUV), v TUV , and (b) with a simple parameterisation based on e-folding depth, v z e . The metric for the evaluation is based upon the deviation of the ratio of the depth-integrated photolysis rate coefficient determined by the two methods,, from unity. The ratio depends primarily on the position of the peak in the photolysis action spectrum of chemical species, solar zenith angle and physical properties of the snowpack, i.e. strong dependence on the light-scattering cross section and the mass ratio of light-absorbing impurity (i.e. black carbon and HULIS) with a weak dependence on density. For the photolysis of NO 2 , the NO

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“…Voisin et al (2012) measured HULIS optical properties and reported them to be consistent with aged biomass burning or a possible marine source. McNeill et al (2012) discussed the adsorption and desorption of organic species to and from snow and ice surfaces, and how these processes influence the transport of organic trace gases through snowpack. Moreover, according to Bond et al (2013), a large fraction of particulate light absorption in Arctic snow (about 30 to 50 %) is due to non-BC constituents and most of the absorption would be due to light-absorbing organic carbon from biofuel and agricultural or boreal forest burning.…”

Section: Impurities In Snowmentioning

confidence: 99%

“…The scientific understanding of the snow organic carbon absorption has started to develop only recently (e.g., McNeill et al, 2012;X. Wang et al, 2013).…”

Section: Impurities In Snowmentioning

confidence: 99%

Spectral albedo of seasonal snow during intensive melt period at Sodankylä, beyond the Arctic Circle

et al. 2013

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Abstract. We have measured spectral albedo, as well as ancillary parameters, of seasonal European Arctic snow at Sodankylä, Finland (67°22' N, 26°39' E). The springtime intensive melt period was observed during the Snow Reflectance Transition Experiment (SNORTEX) in April 2009. The upwelling and downwelling spectral irradiance, measured at 290–550 nm with a double monochromator spectroradiometer, revealed albedo values of ~0.5–0.7 for the ultraviolet and visible range, both under clear sky and variable cloudiness. During the most intensive snowmelt period of four days, albedo decreased from 0.65 to 0.45 at 330 nm, and from 0.72 to 0.53 at 450 nm. In the literature, the UV and VIS albedo for clean snow are ~0.97–0.99, consistent with the extremely small absorption coefficient of ice in this spectral region. Our low albedo values were supported by two independent simultaneous broadband albedo measurements, and simulated albedo data. We explain the low albedo values to be due to (i) large snow grain sizes up to ~3 mm in diameter; (ii) meltwater surrounding the grains and increasing the effective grain size; (iii) absorption caused by impurities in the snow, with concentration of elemental carbon (black carbon) in snow of 87 ppb, and organic carbon 2894 ppb, at the time of albedo measurements. The high concentrations of carbon, detected by the thermal–optical method, were due to air masses originating from the Kola Peninsula, Russia, where mining and refining industries are located.

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Organics in environmental ices: sources, chemistry, and impacts

Cited by 123 publications

References 235 publications

Modelling the physical multiphase interactions of HNO<sub>3</sub> between snow and air on the Antarctic Plateau (Dome C) and coast (Halley)

Modelling the physical multiphase interactions of HNO<sub>3</sub> between snow and air on the Antarctic Plateau (Dome C) and coast (Halley)

The impact of parameterising light penetration into snow on the photochemical production of NO<sub><i>x</i></sub> and OH radicals in snow

Spectral albedo of seasonal snow during intensive melt period at Sodankylä, beyond the Arctic Circle

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Organics in environmental ices: sources, chemistry, and impacts

Cited by 123 publications

References 235 publications

Modelling the physical multiphase interactions of HNO&lt;sub&gt;3&lt;/sub&gt; between snow and air on the Antarctic Plateau (Dome C) and coast (Halley)

Modelling the physical multiphase interactions of HNO&lt;sub&gt;3&lt;/sub&gt; between snow and air on the Antarctic Plateau (Dome C) and coast (Halley)

The impact of parameterising light penetration into snow on the photochemical production of NO&lt;sub&gt;&lt;i&gt;x&lt;/i&gt;&lt;/sub&gt; and OH radicals in snow

Spectral albedo of seasonal snow during intensive melt period at Sodankylä, beyond the Arctic Circle

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Modelling the physical multiphase interactions of HNO<sub>3</sub> between snow and air on the Antarctic Plateau (Dome C) and coast (Halley)

Modelling the physical multiphase interactions of HNO<sub>3</sub> between snow and air on the Antarctic Plateau (Dome C) and coast (Halley)

The impact of parameterising light penetration into snow on the photochemical production of NO<sub><i>x</i></sub> and OH radicals in snow