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Third workshop on Air-Ice Chemical Interactions (AICI)

6–8 Jun 2011
Columbia University
US/Eastern timezone
AICI (June 6-7, 2011) and Snow Chemistry Modeling (June 8, 2011) workshops

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Session

Modeling Workshop

8 Jun 2011, 09:00
Columbia University

Columbia University

New York, NY, USA

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  1. 52. Introduction
    08/06/2011, 09:00
  2. 13. Microstructural Modeling of Snow- and Firn Processes
    Dr Thomas Kaempfer (AF Colenco Ltd / CRREL)
    08/06/2011, 09:15
    The micro-structure of a sintered and porous material impacts its chemical and physical properties. In particular, sintering ice-crystals evolving from snow to firn alter the characteristics of the snowpack. We study the link between micro-structure and properties by numerical modeling based on experimental X-ray micro-tomography data or using discrete element model (DEM) snow as geometrical...
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  3. 10. Comparative molecular dynamics study of vapor-exposed basal, prismatic and pyramidal surfaces of ice
    Dr Martina Roeselova (Institute of Organic Chemistry and Biochemistry ASCR Prague)
    08/06/2011, 09:45
    We present the results of molecular dynamics simulations in which ice Ih slabs with free basal, prismatic, 28 degrees pyramidal, and 14 degrees pyramidal facets are exposed to vapor. All simulations were carried out at 250 K using a six-site intermolecular potential. Characteristics common to all facets include spontaneous development of a quasi-liquid layer (QLL) within ~10 ns, and QLL...
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  4. 64. Parameterizing Trace Gas - Ice Interactions: A look into laboratories
    Thorsten Bartels-Rausch (Paul Scherrer Institut)
    08/06/2011, 10:00
    Recent laboratory experiments that investigated the interaction of atmospheric trace gases with ice surfaces under tropospheric conditions are presented. Key-Questions are a) the importance of surface versus bulk uptake of trace gases b) the effect of trace gas adsorption on the quasiliquid layer c) the influence of the presence of an additional, coadsorbing trace gas on the...
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  5. 53. Discussion: Representing physical and chemical processes on the micro scale in models
    08/06/2011, 10:15
  6. 38. Photolysis rates of nitrate, hydrogen peroxide and nitrite in Arctic and Antarctic snows: A field and modelling study
    Dr Martin King (Royal Holloway University of London)
    08/06/2011, 11:30
    Photolysis of chemicals within snowpacks can produce radical species that initiate oxidation reactions within the snowpack and may be responsible for chemical fluxes from the snowpack. Photolysis rate coefficients as a function of solar zenith angle, snowpack depth and snowpack layer structure are reported using a radiative-transfer model constrained by field measurements of the solar...
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  7. 1. Investigating the Impact of Snowpack Photodenitrification on Antarctic Atmospheric Chemistry Utilizing Results from a Snowpack Radiative Transfer Model in a Global Chemical Transport Model
    Ms Maria Zatko (University of Washington)
    08/06/2011, 11:45
    The photolysis of nitrate (NO3-) in snowpack is a source of NOx to the overlying atmosphere, with implications for the oxidizing capacity of polar atmospheres and the preservation of chemicals in the ice core record. A snowpack radiative transfer model with updated optical properties in the UV [Warren and Clarke, 2008] leads to an e-folding depth of actinic flux in snowpack of 60 cm...
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  8. 54. Discussion: Radiative transfer and photolysis rates in snow
    08/06/2011, 12:00
  9. 66. Development of a mechanistic representation of snow-atmosphere exchange of reactive compounds for implementation in large-scale models
    Laurens Ganzeveld (1Earth System Sciences - Climate Change group, department of Environmental Sciences, Wageningen University and Research Centre, Wageningen, Netherlands)
    08/06/2011, 13:30
    Research on snowpack processes and atmosphere-snow gas exchange has demonstrated that chemical and physical interactions between the snowpack and the overlaying atmosphere have a substantial impact on the composition of the lower troposphere. These observations also imply that deposition, e.g. of ozone to the snowpack and the potential release of reactive oxidized nitrogen, NOx, possibly...
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  10. 36. Reactive halogen release from the polar snowpack and the depletion of ozone and mercury in the air: Insights from 1-D (mechanistic) and 3-D (chemical transport) models
    Dr Kenjiro Toyota (York University / Environment Canada)
    08/06/2011, 14:00
    Reactive halogens, especially bromine, are known to play a major role in the rapid loss of both ozone and gaseous elemental mercury (GEM) in the polar boundary layer during the spring. Measurements of relevant chemical species in the field and from satellites have shown that reactive bromine is released to the high-latitude atmosphere extensively and most notably from the ice-covered ocean....
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  11. 2. How different would tropospheric oxidation be over an ice-free Arctic?
    Dr Apostolos Voulgarakis (NASA Goddard Institute for Space Studies at Columbia University, New York, USA)
    08/06/2011, 14:15
    Climate projections suggest that a complete Arctic sea-ice retreat is likely in the future during summer. Less ice will cause less light reflection and slower tropospheric photolysis. We use a tropospheric chemistry model to examine how oxidation may differ over an ice-free Arctic. We find that late-summer OH concentrations can decrease by 30–60% at polar latitudes, while effects on local...
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  12. 56. Discussion: representing processes in the snow in global models
    08/06/2011, 14:30
  13. 57. Summary + Outlook
    08/06/2011, 16:00
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