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...