1-D Air-snowpack modeling of atmospheric nitrous acid at South Pole during ANTCI 2003

Liao, Wei; Tan, D.

doi:10.5194/acp-8-7087-2008

Cited by 34 publications

(35 citation statements)

References 43 publications

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“…Treatment of photochemistry in surface snow and ice has focused on halogens and nitrate, because laboratory and field studies have clearly shown that both reactive halogens and nitrogen oxides are emitted from irradiated snow and ice. Liao and Tan (2008) integrated simplified chemistry in a 1-D snow model aiming to simulate the formation of HONO in the snow during a 6-day period at the South Pole using prescribed and constant concentrations of nitrate and nitrite. The chemical reactions included the photolysis of NO − 3 assumed to form directly HONO and the photolysis of HONO as its only sink.…”

Section: Chemical Processes In Modelsmentioning

confidence: 99%

“…A similar approach was used to reproduce laboratory experiments investigating the photolysis of nitrate in snow (Honrath et al, 2000;Dubowski et al, 2002;Jacobi and Hilker, 2007;Bock and Jacobi, 2010;Jacobi, 2011). Over time the applied chemical mechanisms were upgraded from very simplified mechanisms as presented by Liao and Tan (2008) to the most advanced model to date presented by Thomas et al (2011). The most advanced model extended an existing atmospheric 1-D chemistry model including gas-phase, aqueous-phase, and heterogeneous chemistry using additional layers to represent chemical processes in the snow.…”

Section: Conclusion About Chemistrymentioning

confidence: 99%

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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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Section: Chemical Processes In Modelsmentioning

confidence: 99%

Section: Conclusion About Chemistrymentioning

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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“…Testing this theory requires the building of a numerical model which represents nitrate recycling at the airsnow interface and describes the evolution of the nitrogen and oxygen stable isotopic composition of nitrate with various constraints from key environmental variables such as the solar zenith angle and the available UV radiation. Various models have been developed to investigate the physical and chemical processes involving nitrate in snow and their impact on the atmospheric chemistry in Antarctica (Wang et al, 2007;Liao and Tan, 2008;Boxe and Saiz-Lopez, 2008) and in Greenland (Jarvis et al, , 2009Kunasek et al, 2008;Thomas et al, 2011;Zatko et al, 2013). Those models are adapted to short time periods (hours to days, typically) and focus on processes at play in the atmosphere and in the nearsurface snowpack.…”

Section: Introductionmentioning

confidence: 99%

Air–snow transfer of nitrate on the East Antarctic Plateau – Part 2: An isotopic model for the interpretation of deep ice-core records

et al. 2015

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Abstract. Unraveling the modern budget of reactive nitrogen on the Antarctic Plateau is critical for the interpretation of ice-core records of nitrate. This requires accounting for nitrate recycling processes occurring in near-surface snow and the overlying atmospheric boundary layer. Not only concentration measurements but also isotopic ratios of nitrogen and oxygen in nitrate provide constraints on the processes at play. However, due to the large number of intertwined chemical and physical phenomena involved, numerical modeling is required to test hypotheses in a quantitative manner. Here we introduce the model TRANSITS (TRansfer of Atmospheric Nitrate Stable Isotopes To the Snow), a novel conceptual, multi-layer and one-dimensional model representing the impact of processes operating on nitrate at the air-snow interface on the East Antarctic Plateau, in terms of concentrations (mass fraction) and nitrogen (δ 15 N) and oxygen isotopic composition ( 17 O excess, 17 O) in nitrate. At the airsnow interface at Dome C (DC; 75• 06 S, 123• 19 E), the model reproduces well the values of δ 15 N in atmospheric and surface snow (skin layer) nitrate as well as in the δ 15 N profile in DC snow, including the observed extraordinary high positive values (around +300 ‰) below 2 cm. The model also captures the observed variability in nitrate mass fraction in the snow. While oxygen data are qualitatively reproduced at the air-snow interface at DC and in East Antarctica, the simulated 17 O values underestimate the observed 17 O values by several per mill. This is explained by the simplifications made in the description of the atmospheric cycling and oxidation of NO 2 as well as by our lack of understanding of the NO x chemistry at Dome C. The model reproduces well the sensitivity of δ 15 N, 17 O and the apparent fractionation constants ( 15 ε app , 17 E app ) to the snow accumulation rate. Building on this development, we propose a framework for the interpretation of nitrate records measured from ice cores. Measurement of nitrate mass fractions and δ 15 N in the nitrate archived in an ice core may be used to derive information about past variations in the total ozone column and/or the primary inputs of nitrate above Antarctica as well as in nitrate trapping efficiency (defined as the ratio between the archived nitrate flux and the primary nitrate input flux). The 17 O of nitrate could then be corrected from the impact of cage recombination effects associated with the photolysis of nitrate in snow. Past changes in the relative contributions of the 17 O in the primary inputs of nitrate and the 17 O in the locally cycled NO 2 and that inherited from the additional O atom in the oxidation of NO 2 could then be determined. Therefore, information about the past variations in the local and long-range processes operating on reactive nitrogen species could be obtained from ice cores collected in lowaccumulation regions such as the Antarctic Plateau.

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“…9 Perhaps because of evidence such as this, the freezing-point depression model is widely used in numerical models of ice and snow (photo)chemistry to describe solute concentrations in the LLRs of ice. [12][13][14][15][16][17] Understanding the composition of LLRs is essential, in part, because values of the freeze-concentration factor can significantly influence the (photo)chemistry of trace species on ice and snow. 2,18 For some reactions the chemical behavior in LLRs is similar to liquid-phase chemistry.…”

Section: Introductionmentioning

confidence: 99%

Using Singlet Molecular Oxygen to Probe the Solute and Temperature Dependence of Liquid-Like Regions in/on Ice

Bower

Anastasio

2013

J. Phys. Chem. A

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TitleUsing singlet molecular oxygen to probe the solute and temperature dependence of liquidlike regions in/on ice freezing-point depression. For ice below its eutectic temperature, the influence of freezingpoint depression on F is damped; the extreme case is with Na 2 SO 4 as the solute, where F shows essentially no agreement with freezing-point depression. In contrast, for ice containing 3 mmol/kg NaCl, measured values of F agree well with freezing-point depression over a range of temperatures, including below the eutectic. Our experiments also reveal that the photon flux in LLRs increases in the presence of salts, which has implications for ice photochemistry in the lab and, perhaps, in the environment.

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1-D Air-snowpack modeling of atmospheric nitrous acid at South Pole during ANTCI 2003

Cited by 34 publications

References 43 publications

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

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

Air–snow transfer of nitrate on the East Antarctic Plateau – Part 2: An isotopic model for the interpretation of deep ice-core records

Using Singlet Molecular Oxygen to Probe the Solute and Temperature Dependence of Liquid-Like Regions in/on Ice

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