06/06/2011, 09:00
What the meeting is for, presentation of the 3 review papers, info on local arragements
Dr
Amanda Grannas
(Villanova University)
06/06/2011, 09:20
It has become increasingly apparent that snow and ice are important media for both homogeneous and heterogeneous environmental chemical reactions. A variety of chemistry occurs in/on snow and ice, including photochemical, redox and biologically-mediated reactions. Organic components play an important role in many of these processes. Organics can be the reactive chromophore or a...
Prof.
Marcelo Guzman
(University of Kentucky)
06/06/2011, 09:50
D. Voisin
(UJF-grenoble / CNRS, LGGE, BP 96, 38402 St Martin d’Heres, France)
06/06/2011, 10:50
Carbonaceous species play critical roles in the interaction of snow with the overlying atmosphere. Elemental or Black Carbon strongly decreases snow albedo, therefore influencing the snow-climate feedback loop. Carbonyls and complex organic molecules such as Humic Like Substances also absorb UV and visible light, therefore influencing photochemistry and light penetration depths in the...
Prof.
Petr Klan
(Masaryk University, Brno, Czech republic)
06/06/2011, 11:10
The freezing of aqueous solutions of most of the organic (and inorganic) compounds causes ice and solute molecules to separate. It results in their increased local concentrations in a liquid (or quasi-liquid) phase covering the ice crystal surface or residing in a limited volume, referred to as micropockets, at the boundary of solid ice. Contrary to this, a shock freezing preparation technique...
Dr
Didier Voisin
(CNRS, Glaciology Laboratory), Dr
Florent Domine
(CNRS, Glaciology Laboratory)
06/06/2011, 11:30
Aldehydes are key reactive species produced by photochemical processes in the snow. They have the potential to be released to the atmosphere, affecting its oxidative capacity. We have performed measurements of formaldehyde, acetaldehyde, glyoxal and methylglyoxal in polar snow, and in particular at Barrow, Alaska, where atmospheric mixing ratios of formaldehyde were also measured. The...
Dr
Martin King
(Royal Holloway University of London)
06/06/2011, 12:05
Poster
Spectral BRDF visible measurements of the Antarctic sea-ice around Terra Nova bay, Antarctica are presented. The BRDF is compared to the physical structure and chemical content of the ice. Satellite observations allow for the synoptic observation of large areas of the globe. However, the reflectance of natural surfaces is not isotropic. The reflectance varies with the illumination and viewing...
Dr
Martin King
(Royal Holloway University of London)
06/06/2011, 12:05
Poster
The climatology and photochemistry of snowpack is dependent on the optical properties of snowpack. Nanogram quantities of light absorbing compounds in a single gram of snow can reduce the albedo, light penetration depth and photochemical production of chemicals such as hydroxyl radicals and nitrogen dioxide within the snowpack. We will present results from the Arctic (Barrow) and...
Hans-Werner Jacobi
(Laboratoire de Glaciologie et Géophysique de l’Environnement LGGE)
06/06/2011, 12:05
Poster
During the OASIS spring campaign 2009 at Barrow, AK, the chemical composition of the snowpack was investigated. More than 110 snow samples including all snow types normally encountered in the snowpack of Alaska’s Arctic Coastal Plain were collected and analyzed regarding major and minor sea salt components. For all species neither distinct temporal trends nor vertical profiles could be...
Mr
Zak Buys
(British Antarctic Survey)
06/06/2011, 12:05
Poster
Tropospheric Ozone Depletion Events (ODEs) have been known, for over 20 years, to occur in polar regions. During such events, ozone concentrations can fall from background amounts to below instrumental detection limits within a few minutes and remain suppressed for on the order of hours to days. The chemical destruction of ozone is driven by halogens (especially bromine radicals) that have a...
Mr
Daniel O'Sullivan
(University College Cork)
06/06/2011, 12:05
Poster
The presence of gaseous halogens in the polar troposphere is of considerable interest to researchers as it is known that these highly reactive species can alter the oxidative capacity of the Polar atmosphere. Perhaps the most well known Polar tropospheric phenomenon to which halogens have been linked are sudden ozone depletion events (ODEs), observed to occur within the boundary layer during...
Dr
Jennie Thomas
(LATMOS/UCLA)
06/06/2011, 12:05
Poster
Reactive halogens in Arctic regions and their impact on ozone levels have been a subject of extensive research since the mid 1980s. In particular, studies have focused on coastal regions close to first-year sea ice. Less is known about halogens in more remote regions, such as the Greenland ice sheet. Motivated by indirect evidence of halogen chemistry, two field campaigns have been conducted...
Dr
Amanda Grannas
(Villanova University)
06/06/2011, 12:05
Poster
Contamination and accumulation of persistent organic pollutants (POPs) in the Arctic, an area previously considered as pristine and removed from human influence, has become a growing concern. Volatile and semi-volatile contaminants from lower latitudes are transported to the Arctic through a process known as global distillation. The polar regions are unique in that they sit in darkness...
Tara Kahan
(University of Colorado Boulder)
06/06/2011, 12:05
Poster
Molecular dynamics (MD) simulations were used to investigate the behaviour of hydroxyl radicals at air-water and air-ice interfaces. Parameters such as orientation at the surface and duration of interactions with the surface varied in expected ways as a function of temperature. This is in contrast to compounds such as aromatic species which have been shown experimentally and theoretically to...
Peter Peterson
(Geophysical Institute and Department of Chemistry and Biochemistry, University of Alaska Fairbanks)
06/06/2011, 12:05
Poster
Because of the ubiquitous nature of ice, chemistry taking place on ice surfaces can have a substantial effect on the environment, particularly in the polar regions, through processes such as ozone depletion and mercury deposition. Frost flowers are an ice form found on newly formed sea ice that have the potential to play a role in halogen activation due to their high salinity. Current...
Mr
Sylvain M. Masclin
(University of California, Merced)
06/06/2011, 12:05
Poster
Interactions between the polar snowpack and the overlying troposphere impact boundary-layer photochemistry and preservation of deposited atmospheric chemical species in snow. The potential of the polar snowpack to act as an H2O2 reservoir and its potential to emit NOx (NO+NO2) from nitrate photolysis in the near-surface snowpack were recently suggested as important factors in altering the...
Min H. Kuo
(Department of Chemical Engineering, Columbia University, New York, NY USA 10027)
06/06/2011, 12:05
Poster
Liquid-like layers on ice significantly influence atmospheric chemistry in polar regions. In the absence of impurities a nanoscale region of surface disorder known as the “quasi-liquid layer” (QLL) may exist at temperatures well beow the bulk melting point (down to ~-30ºC). Surface and bulk impurities are known to modulate the QLL thickness. In aqueous systems containing ionic solutes a liquid...
Dr
Xin Yang
(University of Cambridge)
06/06/2011, 12:05
Poster
In the last several decades, significant depletion of boundary layer ozone (ODEs) has been observed in both Antarctic and Arctic, especially over sea ice zones. ODEs are attributed to catalytic destruction by bromine radicals (Br and BrO), especially during bromine explosion events (BEs), when high concentrations of BrO periodically occur. However, neither the exact source of the bromine nor...
Dr
Céline TOUBIN
(PHLAM)
06/06/2011, 12:05
Poster
The interaction between ice and halogenated species has received much attention in the past few years in the context of atmospheric chemistry and ozone depletion. Much theoretical and experimental work has been carried out in order to understand the HX (X=Cl, Br…) behaviour (adsorption or ionization) at the ice interface. Up to now, very few studies have been dedicated to photolytic processes...
Ms
Sumi Wren
(University of Toronto)
06/06/2011, 12:05
Poster
We used surface-sensitive spectroscopic methods to study the air-ice interface, with a focus on two species: nitrate (NO3ˉ) and protons (H+). Nitrate ions at the surface of frozen Mg(NO3)2(aq) samples were directly measured using glancing-angle Raman spectroscopy. Protons at the surface of frozen water samples, whose pH was adjusted using HNO3, HCl, NaOH or NH4OH, were indirectly measured...
Dr
Markus Frey
(British Antarctic Survey)
06/06/2011, 12:05
Poster
The interpretation of nitrate profiles recorded in deep ice cores is hindered by surface post depositional processes. Deciphering the atmospheric information embedded in these profiles should greatly enhance our understanding of the chemical state of paleo-atmospheres as nitrate potentially contains information about the NOx chemistry. Furthermore, there is now consensus that...
Dr
Markus Frey
(British Antarctic Survey)
06/06/2011, 12:05
Poster
It has been mooted that pernitric acid (HO2NO2) might play an important role in low altitude photochemistry of the polar regions. This potential arises from the intrinsic link between PNA and atmospheric NOx and HOx radicals. For example, gas-phase production and destruction reactions are, respectively, sinks and sources of NOx and HOx. Further, like HNO3, PNA can adsorb to ice/snow surfaces,...
Prof.
Marcelo Guzman
(University of Kentucky)
06/06/2011, 12:05
Poster
The organic matter present in ice and snow is composed of humic-like substances and the transported degradation products of anthropogenic and biogenic emissions. Our research explores the direct photochemistry and thermal reactions of model organic matter in ice and water. Pyruvic (PA) and benzoylformic acids (BA) are used as surrogates for the species present in the polar environment. Several...
Dr
Markus Frey
(British Antarctic Survey)
06/06/2011, 12:05
Poster
Recent studies on atmospheric particulate nitrate (NO3-) have shown that the nitrogen and triple oxygen stable isotopic composition of NO3- allows constraining atmospheric sources and sinks, in particular oxidation pathways of reactive nitrogen. However, extending this tool to past atmospheres using ice cores can be complicated by post-depositional mass loss and fractionation via...
Dr
Rebecca Michelsen
(Randolph-Macon College)
06/06/2011, 12:05
Poster
While the surfaces of ice, snow, and sea ice are known to act as chemical processors that perturb the local atmosphere, the morphology, dynamics, and reactivity of the surface and near-surface regions are not well known. We present a method for studying the near-surface region of frozen aqueous films in the laboratory. Attenuated total reflection infrared spectroscopy (ATR-IR) enables study...
Hans-Werner Jacobi
(Laboratoire de Glaciologie et Géophysique de l’Environnement LGGE)
06/06/2011, 12:05
Poster
It is well known that nitrate in snow is transformed into nitrogen oxides under the influence of solar radiation. However, this process involves multiple physico-chemical steps. One important reactive intermediate is nitrite. To investigate the transformation of nitrate in the snow, we collected surface snow samples every 2 hours for a 36-hour period during the OASIS spring campaign 2009 at...
Dr
Dorothy Durnford
(Independent researcher)
06/06/2011, 12:05
Poster
The fate of mercury deposited onto snow- and ice-covered surfaces is of critical importance for atmospheric mercury models. At high-latitudes, springtime Atmospheric Mercury Depletion Events (AMDEs) are accompanied by important deposition of oxidized mercury to the cryosphere. A significant portion of the deposited mercury may revolatilise from the cryosphere rapidly. However, a combination...
Thorsten Bartels-Rausch
(Paul Scherrer Institut)
06/06/2011, 12:05
Poster
Nitrogen peroxides, such as peroxynitric acid (HO2NO2) act as reservoir for atmospheric NOx and HOx species and thus impact the oxidative capacity of the atmosphere. Mixing ratios of HO2NO2 in the range of 76 pptV have been measured in the upper troposphere. The presence of ice in cirrus clouds there may represent a major sink for HO2NO2, yet little is known about the partitioning to ice...
Patrick Wright
(University of Houston)
06/06/2011, 12:05
Poster
The depth of illumination of UV light in snow is a critical measurement in the study of snow photochemistry. This depth defines the zone where chemical impurities in the snow can photolyze and release reactive trace gases into the atmosphere. Although numerous studies have measured the depth of UV illumination, the physical properties of snow that control snow optics and light extinction are...
Dr
Samar Moussa
(Columbia University)
06/06/2011, 12:05
Poster
The “quasi-liquid layer” (QLL) is a nanoscale region of surface disorder that exists near the melting point of ice (~-30ºC). The presence of this layer is believed to affect gas-ice interactions, uptake coefficients and heterogeneous chemistry in the polar regions. It is also believed that gas-ice interactions can modulate the QLL thickness and induce its formation at temperatures below...
Dr
Christopher Boxe
(NASA-JPL)
06/06/2011, 12:05
Poster
It is well established that the reaction of HO2 with NO plays a central role in atmospheric chemistry by way of OH/HO2 recycling and reduction of ozone depletion by HOx cycles in the stratosphere and in ozone production in the troposphere. In the stratosphere this reaction moderates the effectiveness of the cycle involving HOx radicals, which is an important removal mechanism of ozone. In the...
Prof.
John Sodeau
(University College Cork)
06/06/2011, 13:45
Snow-packs, cirrus clouds, polar stratospheric clouds, frost flowers and sea-ices can all be viewed as part of the Earth’s Cryosphere. Not mere spectactors on chemistry in the atmosphere, ices often play an active role due to the presence of their surfaces, triple points and internal pores. The effects manifest as rate changes for known chemical processes as well as the promotion of...
Mrs
Anna Granfors
(University of Gothenburg, Sweden), Prof.
Katarina Abrahamsson
(University of Gothenburg, Sweden)
06/06/2011, 14:15
Sea ice is thought of as being a barrier for the transportation of dissolved gases between the ocean and the atmosphere. However, sea ice as a source of gases has not been considered to any larger extent. The gaseous fluxes of halocarbons and mercury in polar waters are poorly known, particularly in regards to the role of sea ice. The fluxes are predicted to change in accordance with changes...
Dr
Jennie Thomas
(LATMOS/UCLA)
06/06/2011, 14:35
Motivated by observations of reactive halogens and NOx at Summit, Greenland in the center of the Greenland ice sheet we have developed a 1D model for snow physics and chemistry. This model has been coupled to the boundary layer model MISTRA, which includes detailed multiphase chemistry in the atmosphere and snow. We have developed the model with the goal of understanding how chemical species...
Dr
Markus Frey
(British Antarctic Survey)
07/06/2011, 09:00
The nitrogen oxides NO and NO2 (NOx) play a key role in determining the oxidizing capacity of the boundary layer in high latitudes. Previous Arctic and Antarctic field campaigns have demonstrated that the polar snow pack can release significant amounts of NOx and that one of the major driving mechanisms is UV-photolysis of snow nitrate (NO3-). Unusually high levels of NO observed at South...
Prof.
James DONALDSON
(Department of Chemistry, University of Torontro)
07/06/2011, 09:20
Chemical reactions of importance to the atmosphere are generally assumed to take place at the air-ice interface, where a combination of atmospheric deposition and solute exclusion are thought to give rise to high reagent concentrations. Using glancing-angle fluorescence and Raman spectroscopies we have made direct measurements of photochemical and bimolecular kinetics at this interface, and...
Markus Ammann
(Paul Scherrer Institut)
07/06/2011, 09:50
Ice is a high temperature material in the sense that under environmental conditions it is close to its melting temperature. This leads to peculiarities that determine the physical and chemical properties of the ice - air interface but also the larger scale snow structure. While this is reasonably well understood for pure ice, contaminants present in environmental snow interact with the...
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...
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...
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...
08/06/2011, 10:15
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...
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...
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...
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....
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...
08/06/2011, 14:30
Dr
John Newberg
(Lawrence Berkeley National Laboratory)
Poster
We present results of gas phase and adsorbed phase XPS and NEXAFS spectra of 1-propanol, 2-propanol, acetone, and 1-propanal on ice at -45°C using synchrotron based, ambient pressure X-ray photoemission spectroscopy. Uptake experiments give rise to Langmuirian isotherms. The two alcohols and acetone show little difference in the photoemission spectra between the gas phase and adsorbed phase,...
