Acid ions at triple junction of Antarctic ice observed by Raman scattering

Fukazawa, Hiroshi; Sugiyama, Ken-ichiro; Mae, Shinji; Narita, Hirokazu; Hondoh, Takeo

doi:10.1029/98gl02178

Cited by 91 publications

(98 citation statements)

References 10 publications

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“…3 Maruyama et al, 1992͒, x-ray ͑Kouchi et al, 1987Furukawa and Ishikawa, 1993;Dosch et al, 1995Dosch et al, , 1996Engemann et al, 2004͒, and helium-atom scattering ͑Braun et al, 1998͒. Most have found that interfacial melting begins at much lower temperatures than in surface melting; instead of a range of a few K, the span of interfacial melting may be several tens of degrees.…”

Section: B Interfaces With Solid Substrates: Interfacial Meltingmentioning

confidence: 99%

The physics of premelted ice and its geophysical consequences

2006

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The surface of ice exhibits the swath of phase-transition phenomena common to all materials and as such it acts as an ideal test bed of both theory and experiment. It is readily available, transparent, optically birefringent, and probing it in the laboratory does not require cryogenics or ultrahigh vacuum apparatus. Systematic study reveals the range of critical phenomena, equilibrium and nonequilibrium phase-transitions, and, most relevant to this review, premelting, that are traditionally studied in more simply bound solids. While this makes investigation of ice as a material appealing from the perspective of the physicist, its ubiquity and importance in the natural environment also make ice compelling to a broad range of disciplines in the Earth and planetary sciences. In this review we describe the physics of the premelting of ice and its relationship with the behavior of other materials more familiar to the condensed-matter community. A number of the many tendrils of the basic phenomena as they play out on land, in the oceans, and throughout the atmosphere and biosphere are developed.

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Section: B Interfaces With Solid Substrates: Interfacial Meltingmentioning

confidence: 99%

The physics of premelted ice and its geophysical consequences

2006

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“…The liquid nature of sulphuric acid solutions in triple junctions of Antarctic ice has been shown using Raman microscopy by Fukazawa et al (1998). Koop et al (2000) concluded that sea salt particles remain liquid under environmentally relevant temperatures both as aerosol in the boundfor argon [1] were obtained in a calorimetric study of multilayer adsorption on graphite where the melting temperature is measured as a function of layer thickness.…”

Section: Chemical Impurities In Multiphase Snowmentioning

confidence: 99%

A review of air–ice chemical and physical interactions (AICI): liquids, quasi-liquids, and solids in snow

et al. 2014

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Abstract. Snow in the environment acts as a host to rich chemistry and provides a matrix for physical exchange of contaminants within the ecosystem. The goal of this review is to summarise the current state of knowledge of physical processes and chemical reactivity in surface snow with relevance to polar regions. It focuses on a description of impurities in distinct compartments present in surface snow, such as snow crystals, grain boundaries, crystal surfaces, and liquid parts. It emphasises the microscopic description of the ice surface and its link with the environment. Distinct differences between the disordered air–ice interface, often termed quasi-liquid layer, and a liquid phase are highlighted. The reactivity in these different compartments of surface snow is discussed using many experimental studies, simulations, and selected snow models from the molecular to the macro-scale. Although new experimental techniques have extended our knowledge of the surface properties of ice and their impact on some single reactions and processes, others occurring on, at or within snow grains remain unquantified. The presence of liquid or liquid-like compartments either due to the formation of brine or disorder at surfaces of snow crystals below the freezing point may strongly modify reaction rates. Therefore, future experiments should include a detailed characterisation of the surface properties of the ice matrices. A further point that remains largely unresolved is the distribution of impurities between the different domains of the condensed phase inside the snowpack, i.e. in the bulk solid, in liquid at the surface or trapped in confined pockets within or between grains, or at the surface. While surface-sensitive laboratory techniques may in the future help to resolve this point for equilibrium conditions, additional uncertainty for the environmental snowpack may be caused by the highly dynamic nature of the snowpack due to the fast metamorphism occurring under certain environmental conditions. Due to these gaps in knowledge the first snow chemistry models have attempted to reproduce certain processes like the long-term incorporation of volatile compounds in snow and firn or the release of reactive species from the snowpack. Although so far none of the models offers a coupled approach of physical and chemical processes or a detailed representation of the different compartments, they have successfully been used to reproduce some field experiments. A fully coupled snow chemistry and physics model remains to be developed.

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“…There is however good support for our assumed NO 3 À distribution in ice from observations of its tendency to accumulate at ice grain boundaries and from laboratory measurements. [24,34,35] Future work seeking to address the oxidising capacity due to OH within the snowpack through either measurements of its production and losses, or by direct observation would add support to this work too. The next uncertainty that we discuss again relates to scenario 3 in part two and it is the speciation and abundance of the OM detected in the snowpack.…”

Section: Resultsmentioning

confidence: 99%

“…[32] Concentrations of acidic solutes were found to be present at concentrations of ,10 mM at the South Pole. [33] However, because of the tendency of solutes to migrate to the surface layer in ice, [34,35] concentrations may become locally enhanced up to the 100-mM range [33] in the surface region.…”

Section: Ch 3 Ooh As a Source Of Hchomentioning

confidence: 99%

“…Furthermore, observations of the distribution of acid solutes within ice grains show a tendency for NO 3 À to accumulate at ice grain Chemical production of HCHO in the South Pole snowpack boundaries. [34,35] We also assume that OH produced in the bulk can only penetrate through four monolayers to reach the surface [40] due to the effects of Eqn 6a. Note that the results in Table 1 showing effective OM concentrations for particles of acetophenone of 0.035 mm in diameter are relevant in this scenario.…”

Section: Scenariomentioning

confidence: 99%

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Investigating the photo-oxidative and heterogeneous chemical production of HCHO in the snowpack at the South Pole, Antarctica

et al. 2014

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Environmental context. Snowpacks present a surprisingly active environment for photochemistry, leading to sunlight-induced oxidation of deposited organic matter and the subsequent emission of a variety of photochemically active trace gases. We seek to address questions regarding the ultimate fate of organic matter deposited onto snow in the remote regions of the world. The work is relevant to atmospheric composition and climate change.Abstract. We investigate snowpack fluxes of formaldehyde (HCHO) into the South Pole boundary layer using steadystate photochemical models. We study two chemical sources of HCHO within the snowpack. First, we study chemical production of HCHO from the processing of methyl hydroperoxide (CH 3 OOH): photolysis, reaction with the hydroxyl radical (OH ), and by an acid catalysed rearrangement. Assuming surface layer concentration effects for acidic solutes, we show that the acid catalysed production of HCHO within ice could contribute a non-negligible source to the snowpack HCHO budget. This novel source of HCHO complements existing explanations of HCHO fluxes based on physical emission of HCHO from snow. Secondly, we investigate HCHO production from the oxidation of organic matter (OM) by OH within snow to explain observed fluxes of photochemical origin from the South Pole snowpack. This work shows that laboratory-derived photochemical production rates of HCHO and our standard model are inconsistent with field observations, which has implications for the distribution of OM relative to oxidants within ice particles. We resolve this inconsistency using new laboratory measurements of the molecular dynamics of the OH photofragment from hydrogen peroxide (H 2 O 2 ) and nitrate (NO 3 À ) photolysis, which show that only OH produced in the outermost monolayers can contribute to gas phase and surface layer chemistry. Using these new measurements in conjunction with realistic treatments of ice grain size, H 2 O 2 and NO 3 À distribution within ice grains, diffusion of gas species within solid ice, and observed OM particle size distributions yields snowpack HCHO photochemical production rates more consistent with observations.

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Acid ions at triple junction of Antarctic ice observed by Raman scattering

Cited by 91 publications

References 10 publications

The physics of premelted ice and its geophysical consequences

The physics of premelted ice and its geophysical consequences

A review of air–ice chemical and physical interactions (AICI): liquids, quasi-liquids, and solids in snow

Investigating the photo-oxidative and heterogeneous chemical production of HCHO in the snowpack at the South Pole, Antarctica

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