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Author |
Friedt J-M, Retornaz T, Alzuaga S, Baron T, Martin G, Laroche T, Ballandras S, Griselin M, Simonnet J-P, |
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Title |
Surface acoustic wave devices as passive buried sensors
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Type |
Journal Article |
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Year |
2011 |
Publication |
Journal of Applied Physics |
Abbreviated Journal |
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Volume |
109 |
Issue |
3 |
Pages |
034905-9 |
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Keywords |
delay lines, electrical conductivity, ground penetrating radar, moisture, permittivity, surface acoustic wave sensors, temperature measurement, wireless sensor networks, |
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304 |
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Bachelor's thesis |
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AIP |
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0021-8979 |
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yes |
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3116 |
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Author |
Berthier E., Le Bris R., Mabileau L., Testut L. & Rémy F. |
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Title |
Ice wastage on the Kerguelen Islands (49°S, 69°E) between 1963 and 2006 |
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Journal Article |
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Year |
2009 |
Publication |
Journal of Geophysical Research |
Abbreviated Journal |
J. Geophys. Res. |
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Volume |
114 |
Issue |
F3 |
Pages |
F03005 |
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Keywords |
ice caps, climate change, remote sensing, Kerguelen Islands, Southern Ocean, mass balance. |
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Abstract |
Ce travail qui n'est pas issu du programme 136 utilise des données climatologiques enregistrées Plaine Ampère et fournies par le 136 |
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136 |
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AGU |
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0148-0227 |
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Approved |
yes |
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Call Number |
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Serial |
5933 |
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Author |
Priyadarshi, A.; Dominguez, G.; Savarino, J.; Thiemens, M. |
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Title |
Cosmogenic 35S: A unique tracer to Antarctic atmospheric chemistry and the polar vortex |
Type |
Journal Article |
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Year |
2011 |
Publication |
Geophys. Res. Lett. |
Abbreviated Journal |
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Volume |
38 |
Issue |
13 |
Pages |
L13808 |
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Keywords |
Antarctica; cosmogenic radionuclide; stratosphere-troposphere mixing; 3307 Atmospheric Processes: Boundary layer processes; 3362 Atmospheric Processes: Stratosphere/troposphere interactions; 3363 Atmospheric Processes: Stratospheric dynamics |
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Abstract |
The cosmogenic radionuclide 35S (half life ∼87 d) exists in both 35SO2 gas and 35SO42− aerosol phase in the atmosphere. Cosmogenic 35S fulfils a unique niche in that it has an ideal half-life for use as a tracer of atmospheric processes, possesses a gas phase precursor and undergoes gas to particle conversion, providing a chronometer that complements other measurements of radiogenic isotopes of different half lives and chemical properties. Based on radiogenic 35S measurements and concomitant model calculations, we demonstrate that 35S is a unique tracer to understand stratospheric-tropospheric air mass transport dynamics and the atmospheric oxidation capacity on a short time scale. Reported are the first measurements of 35S contained in SO42− aerosols (bulk and size aggregated) at Antarctica. 35SO42− concentrations at Dome C and Dumont D'Urville exhibit summer maxima and winter minima with a secondary winter peak. Higher oxidative capacity of the atmosphere and long range transport of mid latitude air increases 35SO42− activity in summer whereas a lack of air mass mixing coupled with low oxidant concentration in winter significantly decreases 35SO42− activity. A 3% contribution from stratospheric 35SO42− into the free troposphere during stratosphere-troposphere air mass mixing accounts for the secondary winter 35SO42− peak. In the future, this work will be extended to 35S activity measurements of both gas and aerosol phases to further understand gas to particle conversion, vortex dynamics and trace polar stratospheric cloud sedimentation frequency. |
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1011 |
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AGU |
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0094-8276 |
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yes |
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Call Number |
IPEV @ Thierry.Lemaire @ |
Serial |
6064 |
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Author |
Domine Florent, Gallet Jean-Charles, Barret Manuel, Houdier Stphan, Voisin Didier, Douglas Thomas A, Blum Joel D, Beine Harry J, Anastasio Cort, Bron Franois-Marie, |
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Title |
The specific surface area and chemical composition of diamond dust near Barrow, Alaska
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Type |
Journal Article |
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Year |
2011 |
Publication |
J. Geophys. Res. |
Abbreviated Journal |
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Volume |
116 |
Issue |
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Pages |
D00R06- |
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Keywords |
absorption spectra, aldehydes, dissolved organic carbon, ionic composition, mercury, specific surface area, 0305 Atmospheric Composition and Structure: Aerosols and particles (0345, 4801, 4906), 0317 Atmospheric Composition and Structure: Chemical kinetic and photochemical properties, 0330 Atmospheric Composition and Structure: Geochemical cycles (1030), 0365 Atmospheric Composition and Structure: Troposphere: composition and chemistry, 0736 Cryosphere: Snow (1827, 1863), |
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Abstract |
Diamond dust (DD) refers to tiny ice crystals that form frequently in the Polar troposphere under clear sky conditions. They provide surfaces for chemical reactions and scatter light. We have measured the specific surface area (SSA) of DD at Barrow in March–April 2009. We have also measured its chemical composition in mineral and organic ions, dissolved organic carbon (DOC), aldehydes, H2O2, and the absorption spectra of water-soluble chromophores. Mercury concentrations were also measured in spring 2006, when conditions were similar. The SSA of DD ranges from 79.9 to 223 m2 kg-1. The calculated ice surface area in the atmosphere reaches 11000 (70%) μm2 cm-3, much higher than the aerosol surface area. However, the impact of DD on the downwelling and upwelling light fluxes in the UV and visible is negligible. The composition of DD is markedly different from that of snow on the surface. Its concentrations in mineral ions are much lower, and its overall composition is acidic. Its concentrations in aldehydes, DOC, H2O2 and mercury are much higher than in surface snows. Our interpretation is that DOC from the oceanic surface microlayer, coming from open leads in the ice off of Barrow, is taken up by DD. Active chemistry in the atmosphere takes place on DD crystal surfaces, explaining its high concentrations in aldehydes and mercury. After deposition, active photochemistry modifies DD composition, as seen from the modifications in its absorption spectra and aldehyde and H2O2 content. This probably leads to the emissions of reactive species to the atmosphere.
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1017 |
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AGU |
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ISSN |
0148-0227 |
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Approved |
yes |
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Call Number |
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Serial |
1623 |
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Author |
Baroni, Mlanie; Savarino, Jol; Cole-Dai, J.; Rai, V.K.; Thiemens, M.H. |
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Title |
Anomalous sulfur isotope compositions of volcanic sulfate over the last millennium in Antarctic ice cores |
Type |
Journal Article |
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Year |
2008 |
Publication |
J. Geophys. Res. |
Abbreviated Journal |
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Volume |
113 |
Issue |
D20 |
Pages |
D20112 |
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Keywords |
sulfur isotope anomaly; volcanic eruption; ice cores; 0370 Atmospheric Composition and Structure: Volcanic effects; 0454 Biogeosciences: Isotopic composition and chemistry; 0473 Biogeosciences: Paleoclimatology and paleoceanography; 0724 Cryosphere: Ice cores; 1041 Geochemistry: Stable isotope geochemistry |
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Abstract |
The reconstruction of past volcanism from glaciological archives is based on the measurement of sulfate concentrations in ice. This method does not allow a proper evaluation of the climatic impact of an eruption owing to the uncertainty in classifying an event between stratospheric or tropospheric. This work develops a new method, using anomalous sulfur isotope composition of volcanic sulfate in order to identify stratospheric eruptions over the last millennium. The advantages and limits of this new method are established with the examination of the 10 largest volcanic signals in ice cores from Dome C and South Pole, Antarctica. Of the 10, seven are identified as stratospheric eruptions. Among them, three have been known to be stratospheric (Tambora, Kuwae, the 1259 Unknown Event) and they exhibit anomalous sulfur isotope compositions. Three unknown events (circa 1277, 1230, 1170 A.D.) and the Serua eruption have been identified as stratospheric eruptions, which suggests for the first time that they could have had significant climatic impact. However, the Kuwae and the 1259 Unknown Event stratospheric eruptions exhibit different anomalous sulfur isotope compositions between South Pole and Dome C samples. Differences in sulfate deposition and preservation patterns between the two sites can help explain these discrepancies. This study shows that the presence of an anomalous sulfur isotope composition of volcanic sulfate in ice core indicates a stratospheric eruption, but the absence of such composition does not necessarily lead to the conclusion of a tropospheric process because of differences in the sulfate deposition on the ice sheet. |
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Programme |
1011 |
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AGU |
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Abbreviated Series Title |
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ISSN |
0148-0227 |
ISBN |
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Approved |
yes |
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Call Number |
IPEV @ Thierry.Lemaire @ |
Serial |
6048 |
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Author |
Barret Manuel, Domine Florent, Houdier Stephan, Gallet Jean-Charles, Weibring Petter, Walega James, Fried Alan, Richter Dirk, |
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Title |
Formaldehyde in the Alaskan Arctic snowpack: Partitioning and physical processes involved in air-snow exchanges
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Type |
Journal Article |
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Year |
2011 |
Publication |
J. Geophys. Res. |
Abbreviated Journal |
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Volume |
116 |
Issue |
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Pages |
D00R03- |
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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), |
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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.
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Programme |
1017 |
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Publisher |
AGU |
Place of Publication |
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ISSN |
0148-0227 |
ISBN |
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Notes |
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Approved |
yes |
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Call Number |
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Serial |
1029 |
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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, |
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Title |
Carbonaceous species and humic like substances (HULIS) in Arctic snowpack during OASIS field campaign in Barrow
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Type |
Journal Article |
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Year |
2012 |
Publication |
J. Geophys. Res. |
Abbreviated Journal |
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Volume |
117 |
Issue |
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Pages |
D00R19- |
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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), |
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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.
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1017 |
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AGU |
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ISSN |
0148-0227 |
ISBN |
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Approved |
yes |
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Call Number |
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Serial |
841 |
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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, |
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Title |
An isotopic view on the connection between photolytic emissions of NOx from the Arctic snowpack and its oxidation by reactive halogens
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Type |
Journal Article |
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Year |
2012 |
Publication |
J. Geophys. Res. |
Abbreviated Journal |
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Volume |
117 |
Issue |
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Pages |
D00R08- |
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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), |
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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.
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Programme |
1017 |
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Thesis |
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Publisher |
AGU |
Place of Publication |
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Summary Language |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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ISSN |
0148-0227 |
ISBN |
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Medium |
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Expedition |
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Conference |
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Notes |
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Approved |
yes |
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Call Number |
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Serial |
1881 |
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Author |
Homberg, C.; Bergerat, F.; Angelier, J.; Garcia, S. |
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Title |
Fault interaction and stresses along broad oceanic transform zone: Tjrnes Fracture Zone, north Iceland |
Type |
Journal Article |
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Year |
2010 |
Publication |
Tectonics |
Abbreviated Journal |
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Volume |
29 |
Issue |
1 |
Pages |
TC1002 |
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Keywords |
oceanic transform; fault interaction; stresses; Iceland; slip transfer; 8150 Tectonophysics: Plate boundary: general; 8164 Tectonophysics: Stresses: crust and lithosphere; 8020 Structural Geology: Mechanics, theory, and modeling |
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Abstract |
Transform motion along oceanic transforms generally occurs along narrow faults zones. Another class of oceanic transforms exists where the plate boundary is quite large (∼100 km) and includes several subparallel faults. Using a 2-D numerical modeling, we simulate the slip distribution and the crustal stress field geometry within such broad oceanic transforms (BOTs). We examine the possible configurations and evolution of such BOTs, where the plate boundary includes one, two, or three faults. Our experiments show that at any time during the development of the plate boundary, the plate motion is not distributed along each of the plate boundary faults but mainly occurs along a single master fault. The finite width of a BOT results from slip transfer through time with locking of early faults, not from a permanent distribution of deformation over a wide area. Because of fault interaction, the stress field geometry within the BOTs is more complex than that along classical oceanic transforms and includes stress deflections close to but also away from the major faults. Application of this modeling to the 100 km wide Tjrnes Fracture Zone (TFZ) in North Iceland, a major BOT of the Mid-Atlantic Ridge that includes three main faults, suggests that the Dalvik Fault and the Husavik-Flatey Fault developed first, the Grismsey Fault being the latest active structure. Since initiation of the TFZ, the Husavik-Flatey Fault accommodated most of the plate motion and probably persists until now as the main plate structure. |
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Programme |
316 |
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AGU |
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ISSN |
0278-7407 |
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Notes |
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Approved |
yes |
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Call Number |
IPEV @ Thierry.Lemaire @ |
Serial |
6062 |
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Author |
Gros V, Poisson N, Martin D, Kanakidou M, Bonsang B, |
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Title |
Observations and modeling of the seasonal variation of surface ozone at Amsterdam Island: 1994–1996 |
Type |
Journal Article |
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Year |
1998 |
Publication |
J. Geophys. Res. |
Abbreviated Journal |
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Volume |
103 |
Issue |
D21 |
Pages |
28103 -28109 |
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Keywords |
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Abstract |
Since January 1994, continuous surface O3 measurements have been carried out at Amsterdam Island (37°S, 77°E) in the southern Indian Ocean using a UV absorption analyzer. Mean O3 concentrations and standard deviations are recorded every 5 min. This paper shows and discusses the O3 time series for a 3-year period (1994–1996). During this period, O3 shows a seasonal variation with maxima around 30 ppbv during winter (July – September) and minima around 13 ppbv during summer (December – February). O3 levels at Amsterdam Island are close to those observed at Cape Grim (Tasmania, 41°S, 145°E) for the period of 1991 to 1995. In order to improve the understanding of the mechanisms controlling the O3 seasonal variation at Amsterdam Island, our observations have been analyzed by using the global three-dimensional climatological Model of the Global Universal Tracer Transport in the Atmosphere (MOGUNTIA). The model reproduces well the observed O3 mixing ratios and their seasonal cycle. The seasonal variation of stratospheric origin O3 calculated by MOGUNTIA shows a maximum of 18 ppbv in September and a minimum of 13 ppbv in April. The oxidation of continentally emitted O3 precursors during their transport to Amsterdam Island contributes to the photochemical production of O3 by up to 12 ppbv during austral summer. From this amount, 3–7 ppbv are directly linked to nonmethane hydrocarbon oxidation chemistry under relatively high NOx conditions. In particular, biomass burning emissions contribute up to 5.5 ppbv to the observed O3 levels in September. Both photochemical production by biomass burning and stratospheric influx of O3 lead to a maximum in O3 mixing ratios during late winter to early spring in agreement with the observations. Minimum O3 mixing ratios observed during austral summer are related to photochemical O3 depletion. |
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AGU |
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0148-0227 |
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28 |
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