| Records |
| Author |
Simon Ducatez, Sébastien Dalloyau, Pierre Richard, Christophe Guinet, Yves Cherel |
| Title |
Stable isotopes document winter trophic ecology and maternal investment of adult female southern elephant seals (Mirounga leonina) breeding at the Kerguelen Islands |
Type |
Journal |
| Year |
2008 |
Publication |
Marine Biology |
Abbreviated Journal  |
|
| Volume |
155 |
Issue |
4 |
Pages |
413-420 |
| Keywords |
|
| Abstract |
Individual specialisation is widespread and can affect a population’s ecological and evolutionary dynamics. Whether intra-specific niche differences can influence reproductive investment was examined in a marine mammal, the southern elephant seal (Mirounga leonina), whose females were known to forage in two different areas during the austral winter. The study was conducted at Kerguelen Islands (49°21′S, 70°18′E), southern Indian Ocean, in late winter–early spring 2006. Pups were used as proxies of their mothers’ biology and combined information on their weaning mass (a proxy of females’ foraging success and short-term fitness) together with their blood δ13C value (a proxy of female foraging zone). First, the use of isotopic signature of pups was validated to study the female foraging ecology during their pre-breeding trip by demonstrating that δ13C and δ15N values of pups and their mothers were positively and linearly correlated. Then, blood samples were taken from a large number of newly-weaned pups, which were also weighed, to provide information at the population level. Estimated δ13C values of female seals encompassed a large range of values (from −23.7 to −19.1‰) with an unimodal frequency distribution, suggesting no contrasted foraging areas within the population. No significant relationship was found between pup weaning mass and their carbon signature, indicating no link between female foraging areas and maternal foraging success and investment. Finally, blood δ13C and δ15N values gave new insights into southern elephant seal ecology, suggesting that females mainly foraged north of the Polar Front where they preyed upon myctophid fish in late winter. |
| Programme |
109 |
| Campaign |
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| Address |
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| Corporate Author |
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Thesis |
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| Publisher |
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Place of Publication |
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Editor |
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| Language |
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Summary Language |
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Original Title |
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| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
|
Edition |
|
| ISSN |
1432-1793 |
ISBN |
|
Medium |
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| Area |
|
Expedition |
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Conference |
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| Notes |
|
Approved |
yes |
| Call Number |
|
Serial |
5697 |
| Permanent link to this record |
| |
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| |
| Author |
Barret Manuel, Domine Florent, Houdier Stephan, Gallet Jean-Charles, Weibring Petter, Walega James, Fried Alan, Richter Dirk, |
| Title |
Formaldehyde in the Alaskan Arctic snowpack: Partitioning and physical processes involved in air-snow exchanges
|
Type |
Journal Article |
| Year |
2011 |
Publication |
J. Geophys. Res. |
Abbreviated Journal |
|
| Volume |
116 |
Issue |
|
Pages |
D00R03- |
| Keywords |
adsorption, carbonyls, diffusion, halogen, solid-solution, 0322 Atmospheric Composition and Structure: Constituent sources and sinks, 0365 Atmospheric Composition and Structure: Troposphere: composition and chemistry, 0736 Cryosphere: Snow (1827, 1863), 3307 Atmospheric Processes: Boundary layer processes, 9315 Geographic Location: Arctic region (0718, 4207), |
| Abstract |
The snowpack is a photochemically active medium which produces numerous key reactive species involved in the atmospheric chemistry of polar regions. Formaldehyde (HCHO) is one such reactive species produced in the snow, and which can be released to the atmospheric boundary layer. Based on atmospheric and snow measurements, this study investigates the physical processes involved in the HCHO air-snow exchanges observed during the OASIS 2009 field campaign at Barrow, Alaska. HCHO concentration changes in a fresh diamond dust layer are quantitatively explained by the equilibration of a solid solution of HCHO in ice, through solid-state diffusion of HCHO within snow crystals. Because diffusion of HCHO in ice is slow, the size of snow crystals is a major variable in the kinetics of exchange and the knowledge of the snow specific surface area is therefore crucial. Air-snow exchanges of HCHO can thus be explained without having to consider processes taking place in the quasi-liquid layer present at the surface of ice crystals. A flux of HCHO to the atmosphere was observed simultaneously with an increase of HCHO concentration in snow, indicating photochemical production in surface snow. This study also suggests that the difference in bromine chemistry between Alert (Canadian Arctic) and Barrow leads to different snow composition and post-deposition evolutions. The highly active bromine chemistry at Barrow probably leads to low HCHO concentrations at the altitude where diamond dust formed. Precipitated diamond dust was subsequently undersaturated with respect to thermodynamic equilibrium, which contrasts to what was observed elsewhere in previous studies.
|
| Programme |
1017 |
| Campaign |
|
| Address |
|
| Corporate Author |
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Thesis |
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| Publisher |
AGU |
Place of Publication |
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Editor |
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| Language |
|
Summary Language |
|
Original Title |
|
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
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| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0148-0227 |
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
|
Approved |
yes |
| Call Number |
|
Serial |
1029 |
| Permanent link to this record |
| |
|
| |
| Author |
Voisin Didier, Jaffrezo Jean-Luc, Houdier Stphan, Barret Manuel, Cozic Julie, King Martin D, France James L, Reay Holly J, Grannas Amanda, Kos Gregor, Ariya Parisa A, Beine Harry J, Domine Florent, |
| Title |
Carbonaceous species and humic like substances (HULIS) in Arctic snowpack during OASIS field campaign in Barrow
|
Type |
Journal Article |
| Year |
2012 |
Publication |
J. Geophys. Res. |
Abbreviated Journal |
|
| Volume |
117 |
Issue |
|
Pages |
D00R19- |
| Keywords |
HULIS, OASIS, carbonaceous species, snow chemistry, snow metamorphism, 0305 Atmospheric Composition and Structure: Aerosols and particles (0345, 4801, 4906), 0706 Cryosphere: Active layer, 0736 Cryosphere: Snow (1827, 1863), |
| Abstract |
Snowpacks contain many carbonaceous species that can potentially impact on snow albedo and arctic atmospheric chemistry. During the OASIS field campaign, in March and April 2009, Elemental Carbon (EC), Water insoluble Organic Carbon (WinOC) and Dissolved Organic Carbon (DOC) were investigated in various types of snow: precipitating snows, remobilized snows, wind slabs and depth hoars. EC was found to represent less than 5% of the Total Carbon Content (TCC = EC + WinOC + DOC), whereas WinOC was found to represent an unusual 28 to 42% of TCC. Snow type was used to infer physical processes influencing the evolution of different fractions of DOC. DOC is highest in soil influenced indurated depth hoar layers due to specific wind related formation mechanisms in the early season. Apart from this specific snow type, DOC is found to decrease from precipitating snow to remobilized snow to regular depth hoar. This decrease is interpreted as due to cleaving photochemistry and physical equilibration of the most volatile fraction of DOC. Depending on the relative proportions of diamond dust and fresh snow in the deposition of the seasonal snowpack, we estimate that 31 to 76% of DOC deposited to the snowpack is reemitted back to the boundary layer. Under the assumption that this reemission is purely photochemical, we estimate an average flux of VOC out of the snowpack of 20 to 170 μgC m-2 h-1. Humic like substances (HULIS), short chain diacids and aldehydes are quantified, and showed to represent altogether a modest (<20%) proportion of DOC, and less than 10% of DOC + WinOC. HULIS optical properties are measured and could be consistent with aged biomass burning or a possible marine source.
|
| Programme |
1017 |
| Campaign |
|
| Address |
|
| Corporate Author |
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Thesis |
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| Publisher |
AGU |
Place of Publication |
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Editor |
|
| Language |
|
Summary Language |
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Original Title |
|
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
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| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0148-0227 |
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
|
Approved |
yes |
| Call Number |
|
Serial |
841 |
| Permanent link to this record |
| |
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| |
| Author |
Morin S, Erbland J, Savarino J, Domine F, Bock J, Friess U, Jacobi H-W, Sihler H, Martins J M F, |
| Title |
An isotopic view on the connection between photolytic emissions of NOx from the Arctic snowpack and its oxidation by reactive halogens
|
Type |
Journal Article |
| Year |
2012 |
Publication |
J. Geophys. Res. |
Abbreviated Journal |
|
| Volume |
117 |
Issue |
|
Pages |
D00R08- |
| Keywords |
halogen, isotopes, nitrate, ozone, 0305 Atmospheric Composition and Structure: Aerosols and particles (0345, 4801, 4906), 0365 Atmospheric Composition and Structure: Troposphere: composition and chemistry, 0454 Biogeosciences: Isotopic composition and chemistry (1041, 4870), 0736 Cryosphere: Snow (1827, 1863), 9315 Geographic Location: Arctic region (0718, 4207), |
| Abstract |
We report on dual isotopic analyses (δ15N and Δ17O) of atmospheric nitrate at daily time-resolution during the OASIS intensive field campaign at Barrow, Alaska, in March–April 2009. Such measurements allow for the examination of the coupling between snowpack emissions of nitrogen oxides (NOx = NO + NO2) and their involvement in reactive halogen-mediated chemical reactions in the Arctic atmosphere. The measurements reveal that during the spring, low δ15N values in atmospheric nitrate, indicative of snowpack emissions of NOx, are almost systematically associated with local oxidation of NOx by reactive halogens such as BrO, as indicated by 17O-excess measurements (Δ17O). The high time-resolution data from the intensive field campaign were complemented by weekly aerosol sampling between April 2009 and February 2010. The dual isotopic composition of nitrate (δ15N and Δ17O) obtained throughout this nearly full seasonal cycle is presented and compared to other seasonal-scale measurements carried out in the Arctic and in non-polar locations. In particular, the data allow for the investigation of the seasonal variations of reactive halogen chemistry and photochemical snowpack NOx emissions in the Arctic. In addition to the well characterized peak of snowpack NOx emissions during springtime in the Arctic (April to May), the data reveal that photochemical NOx emissions from the snowpack may also occur in other seasons as long as snow is present and there is sufficient UV radiation reaching the Earth's surface.
|
| Programme |
1017 |
| Campaign |
|
| Address |
|
| Corporate Author |
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Thesis |
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| Publisher |
AGU |
Place of Publication |
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Editor |
|
| Language |
|
Summary Language |
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Original Title |
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| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
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| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0148-0227 |
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
|
Approved |
yes |
| Call Number |
|
Serial |
1881 |
| Permanent link to this record |
| |
|
| |
| Author |
Gouttevin I, Menegoz M, Domin F, Krinner G, Koven C, Ciais P, Tarnocai C, Boike J, |
| Title |
How the insulating properties of snow affect soil carbon distribution in the continental pan-Arctic area
|
Type |
Journal Article |
| Year |
2012 |
Publication |
J. Geophys. Res. |
Abbreviated Journal |
|
| Volume |
117 |
Issue |
G2 |
Pages |
G02020- |
| Keywords |
Arctic, land-surface model, permafrost, snow, snow insulation, soil carbon, 0414 Biogeosciences: Biogeochemical cycles, processes, and modeling (0412, 0793, 1615, 4805, 4912), 0475 Biogeosciences: Permafrost, cryosphere, and high-latitude processes (0702, 0716), 1622 Global Change: Earth system modeling (1225, 4316), |
| Abstract |
We demonstrate the effect of an ecosystem differentiated insulation by snow on the soil thermal regime and on the terrestrial soil carbon distribution in the pan-Arctic area. This is done by means of a sensitivity study performed with the land surface model ORCHIDEE, which furthermore provides a first quantification of this effect. Based on field campaigns reporting higher thermal conductivities and densities for the tundra snowpack than for taiga snow, two distributions of near-equilibrium soil carbon stocks are computed, one relying on uniform snow thermal properties and the other using ecosystem-differentiated snow thermal properties. Those modeled distributions strongly depend on soil temperature through decomposition processes. Considering higher insulation by snow in taiga areas induces warmer soil temperatures by up to 12 K in winter at 50 cm depth. This warmer soil signal persists over summer with a temperature difference of up to 4 K at 50 cm depth, especially in areas exhibiting a thick, enduring snow cover. These thermal changes have implications on the modeled soil carbon stocks, which are reduced by 8% in the pan-Arctic continental area when the vegetation-induced variations of snow thermal properties are accounted for. This is the result of diverse and spatially heterogeneous ecosystem processes: where higher soil temperatures lift nitrogen limitation on plant productivity, tree plant functional types thrive whereas light limitation and enhanced water stress are the new constrains on lower vegetation, resulting in a reduced net productivity at the pan-Arctic scale. Concomitantly, higher soil temperatures yield increased respiration rates (+22% over the study area) and result in reduced permafrost extent and deeper active layers which expose greater volumes of soil to microbial decomposition. The three effects combine to produce lower soil carbon stocks in the pan-Arctic terrestrial area. Our study highlights the role of snow in combination with vegetation in shaping the distribution of soil carbon and permafrost at high latitudes.
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| Programme |
1017 |
| Campaign |
|
| Address |
|
| Corporate Author |
|
Thesis |
|
| Publisher |
AGU |
Place of Publication |
|
Editor |
|
| Language |
|
Summary Language |
|
Original Title |
|
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
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| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0148-0227 |
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
|
Approved |
yes |
| Call Number |
|
Serial |
776 |
| Permanent link to this record |
| |
|
| |
| Author |
Gusmeroli Alessio, Pettit Erin C, Kennedy Joseph H, Ritz Catherine, |
| Title |
The crystal fabric of ice from full-waveform borehole sonic logging
|
Type |
Journal Article |
| Year |
2012 |
Publication |
J. Geophys. Res. |
Abbreviated Journal |
|
| Volume |
117 |
Issue |
F3 |
Pages |
F03021- |
| Keywords |
Ice anisotropy, borehole sonic logging, ice crystal fabric, 0726 Cryosphere: Ice sheets, 0915 Exploration Geophysics: Downhole methods, 0935 Exploration Geophysics: Seismic methods (3025, 7294), |
| Abstract |
In an ice sheet, a preferred crystal orientation fabric affects deformation rates because ice crystals are strongly anisotropic: shear along the basal plane is significantly easier than shear perpendicular to the basal plane. The effect of fabric can be as important as temperature in defining deformation rates. Fabric is typically measured using analysis of thin sections under the microscope with co-polarized light. Due to the time-consuming and destructive nature of these measurements, however, it is difficult to capture the spatial variation in fabric necessary for evincing ice sheet flow patterns. Because an ice crystal is similarly elastically anisotropic, the speed of elastic waves through ice can be used as a proxy for quantify anisotropy. We use borehole sonic logging measurements and thin section data from Dome C, East Antarctica to define the relations between apparent fabric and borehole measured elastic speeds (compressional VP and vertically polarized shear VSV). These relations, valid for single maximum fabrics, allow in-situ, depth-continuous fabric estimates of unimodal fabric strength from borehole sonic logging. We describe the single maximum fabric using a1: the largest eigenvalue of the second-order orientation tensor. For ice at -16C and a1 in the 0.7-1 range the relations are VP = 248 a13.7 + 3755 m s-1 and VSV = -210a17.3 + 1968 m s-1.
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| Programme |
902 |
| Campaign |
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| Address |
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| Corporate Author |
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Thesis |
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| Publisher |
AGU |
Place of Publication |
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Editor |
|
| Language |
|
Summary Language |
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Original Title |
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| Series Editor |
|
Series Title |
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Abbreviated Series Title |
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| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0148-0227 |
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
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| Notes |
|
Approved |
yes |
| Call Number |
|
Serial |
505 |
| Permanent link to this record |
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| |
| Author |
N. Crouzet, T. Guillot, A. Agabi, Y. Fanteï-Caujolle, F. Fressin, J.-P. Rivet, E. Bondoux, Z. Challita, L. Abe, A. Blazit, S. Bonhomme, J.-B. Daban, C. Gouvret, D. Mékarnia, F.-X. Schmider, F. Valbousquet |
| Title |
Photometric quality of Dome C for the winter 2008 from ASTEP South |
Type |
Journal |
| Year |
2010 |
Publication |
EAS Publications Series |
Abbreviated Journal |
|
| Volume |
40 |
Issue |
|
Pages |
367-373 |
| Keywords |
|
| Abstract |
ASTEP South is an Antarctic Search for Transiting ExoPlanets in the South pole field, from the Concordia station, Dome C, Antarctica. The instrument consists of a thermalized 10 cm refractor observing a fixed 3.88° × 3.88° field of view to perform photometry of several thousand stars at visible wavelengths (700–900 nm). The first winter campaign in 2008 led to the retrieval of nearly 1600 hours of data. We derive the fraction of photometric nights by measuring the number of detectable stars in the field. The method is sensitive to the presence of small cirrus clouds which are invisible to the naked eye. The fraction of night-time for which at least 50% of the stars are detected is 74% from June to September 2008. Most of the lost time (18.5% out of 26%) is due to periods of bad weather conditions lasting for a few days (“white outs”). Extended periods of clear weather exist. For example, between July 10 and August 10, 2008, the total fraction of time (day+night) for which photometric observations were possible was 60%. This confirms the very high quality of Dome C for nearly continuous photometric observations during the Antarctic winter. |
| Programme |
1066 |
| Campaign |
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| Address |
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| Corporate Author |
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Thesis |
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| Publisher |
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Place of Publication |
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Editor |
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| Language |
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Summary Language |
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Original Title |
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| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
|
| ISSN |
1633-4760, 1638-1963 |
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
|
Approved |
yes |
| Call Number |
|
Serial |
5514 |
| Permanent link to this record |
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| |
| Author |
Beine Harry, Anastasio Cort, Esposito Giulio, Patten Kelley, Wilkening Elizabeth, Domine Florent, Voisin Didier, Barret Manuel, Houdier Stephan, Hall Sam, |
| Title |
Soluble, light-absorbing species in snow at Barrow, Alaska
|
Type |
Journal Article |
| Year |
2011 |
Publication |
J. Geophys. Res. |
Abbreviated Journal |
|
| Volume |
116 |
Issue |
|
Pages |
D00R05- |
| Keywords |
HULIS, OASIS, chromophores, light absorption, snow pack, 0317 Atmospheric Composition and Structure: Chemical kinetic and photochemical properties, 0322 Atmospheric Composition and Structure: Constituent sources and sinks, 0365 Atmospheric Composition and Structure: Troposphere: composition and chemistry, 0736 Cryosphere: Snow (1827, 1863), |
| Abstract |
As part of the international multidisciplinary Ocean – Atmosphere – Sea Ice – Snowpack (OASIS) program we analyzed more than 500 terrestrial (melted) snow samples near Barrow, AK between February and April 2009 for light absorption, as well as H2O2 and inorganic anion concentrations. For light absorption in the photochemically active region (300–450 nm) of surface snows, H2O2 and NO3- make minor contributions (combined < 9% typically), while HUmic LIke Substances (HULIS) and unknown chromophores each account for approximately half of the total absorption. We have identified four main sources for our residual chromophores (i.e., species other than H2O2 or NO3-): (1) vegetation and organic debris impact mostly the lowest 20 cm of the snowpack, (2) marine inputs, which are identified by high Cl- and SO42- contents, (3) deposition of diamond dust to surface snow, and (4) gas-phase exchange between the atmosphere and surface snow layers. The snow surfaces, and accompanying chromophore concentrations, are strongly modulated by winds and snowfall at Barrow. However, even with these physical controls on light absorption, we see an overall decline of light absorption in near-surface snow during the 7 weeks of our campaign, likely due to photo-bleaching of chromophores. While HULIS and unknown chromophores dominate light absorption by soluble species in Barrow snow, we know little about the photochemistry of these species, and thus we as a community are probably overlooking many snowpack photochemical reactions.
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| Programme |
1017 |
| Campaign |
|
| Address |
|
| Corporate Author |
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Thesis |
|
| Publisher |
AGU |
Place of Publication |
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Editor |
|
| Language |
|
Summary Language |
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Original Title |
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| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
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| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0148-0227 |
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
|
Approved |
yes |
| Call Number |
|
Serial |
1145 |
| Permanent link to this record |
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| |
| Author |
Domine Florent, Bock Josu, Morin Samuel, Giraud Grald, |
| Title |
Linking the effective thermal conductivity of snow to its shear strength and density
|
Type |
Journal Article |
| Year |
2011 |
Publication |
J. Geophys. Res. |
Abbreviated Journal |
|
| Volume |
116 |
Issue |
F4 |
Pages |
F04027- |
| Keywords |
avalanche, shear strength, snow, thermal conductivity, 0736 Cryosphere: Snow (1827, 1863), 0742 Cryosphere: Avalanches (4302), 0770 Cryosphere: Properties, 0776 Cryosphere: Glaciology (1621, 1827, 1863), |
| Abstract |
The effective thermal conductivity of snow, keff, is a crucial climatic and environmental variable. Here, we test the intuition that keff is linked to microstructural and mechanical properties by attempting to relate keff to density ρsnow, and to shear strength σ measured with a handheld shear vane. We performed 106 combined measurements of keff, ρsnow and σ in the Alps, Svalbard, Arctic Alaska, and near the North Pole, covering essentially all snow types. We find a good correlation between keff and ρsnow which is not significantly different from that of Sturm et al. (1997). The correlation between keff and a combination of σ and ρsnow is stronger than with density alone. We propose an equation linking keff, (W m-1 K-1) ρsnow (kg m-3) and σ (Pa): keff = 7.114 10-5 ρsnow σ0.333 + 2.367 10-2. This equation places constraints on the calculation of keff, ρsnow and σ in avalanche warning models where σ is a key variable. For our samples, we calculate σ from measured values of keff and ρsnow using our equation and compare the value to that predicted by the French MEPRA avalanche warning model, which uses density and grain type as input data. MEPRA and the prediction of σ based on keff and ρsnow agree within 8%. MEPRA agrees with observations within 11%. Calculating σ from density only yields values 55% lower than measured, showing the interest of using additional data to predict σ.
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| Programme |
1017 |
| Campaign |
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| Address |
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| Corporate Author |
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Thesis |
|
| Publisher |
AGU |
Place of Publication |
|
Editor |
|
| Language |
|
Summary Language |
|
Original Title |
|
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0148-0227 |
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
|
Approved |
yes |
| Call Number |
|
Serial |
1171 |
| Permanent link to this record |
| |
|
| |
| Author |
Beine Harry, Anastasio Cort, Domine Florent, Douglas Thomas, Barret Manuel, France James, King Martin, Hall Sam, Ullmann Kirk, |
| Title |
Soluble chromophores in marine snow, seawater, sea ice and frost flowers near Barrow, Alaska
|
Type |
Journal Article |
| Year |
2012 |
Publication |
J. Geophys. Res. |
Abbreviated Journal |
|
| Volume |
117 |
Issue |
|
Pages |
D00R15- |
| Keywords |
OASIS, chromophores, colored dissolved organic matter (CDOM), frost flowers, light absorption, marine, 0317 Atmospheric Composition and Structure: Chemical kinetic and photochemical properties, 0322 Atmospheric Composition and Structure: Constituent sources and sinks, 0736 Cryosphere: Snow (1827, 1863), 0750 Cryosphere: Sea ice (4540), 4807 Oceanography: Biological and Chemical: Chemical speciation and complexation, |
| Abstract |
We measured light absorption in 42 marine snow, sea ice, seawater, brine, and frost flower samples collected during the OASIS field campaign between February 27 and April 15, 2009. Samples represented multiple sites between landfast ice and open pack ice in coastal areas approximately 5 km west of Barrow, Alaska. The chromophores that are most commonly measured in snow, H2O2, NO3-, and NO2-, on average account for less than 1% of sunlight absorption in our samples. Instead, light absorption is dominated by unidentified “residual” species, likely organic compounds. Light absorption coefficients for the frost flowers on first-year sea ice are, on average, 40 times larger than values for terrestrial snow samples at Barrow, suggesting very large rates of photochemical reactions in frost flowers. For our marine samples the calculated rates of sunlight absorption and OH production from known chromophores are (0.1–1.4) 1014 (photons cm-3 s-1) and (5–70) 10-12 (mol L-1 s-1), respectively. Our residual spectra are similar to spectra of marine chromophoric dissolved organic matter (CDOM), suggesting that CDOM is the dominant chromophore in our samples. Based on our light absorption measurements we estimate dissolved organic carbon (DOC) concentrations in Barrow seawater and frost flowers as approximately 130 and 360 μM C, respectively. We expect that CDOM is a major source of OH in our marine samples, and it is likely to have other significant photochemistry as well.
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| Programme |
1017 |
| Campaign |
|
| Address |
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| Corporate Author |
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Thesis |
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| Publisher |
AGU |
Place of Publication |
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Editor |
|
| Language |
|
Summary Language |
|
Original Title |
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| Series Editor |
|
Series Title |
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Abbreviated Series Title |
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| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0148-0227 |
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
|
Approved |
yes |
| Call Number |
|
Serial |
989 |
| Permanent link to this record |
