| Records |
| Author |
Shaheen Robina, Abauanza Mariana, Jackson Teresa L, McCabe Justin, Savarino Joel, Thiemens Mark H, |
| Title |
Tales of volcanoes and El-NiƱo southern oscillations with the oxygen isotope anomaly of sulfate aerosol
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Type |
Journal Article |
| Year |
2013 |
Publication |
PROCEEDINGS OF THE AMERICAN ACADEMY OF ARTS AND SCIENCES |
Abbreviated Journal |
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| Volume |
110 |
Issue |
44 |
Pages |
17662-17667 |
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| Abstract |
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Programme  |
1011 |
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Thesis |
Bachelor's thesis |
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Edition |
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| ISSN |
0027-8424 |
ISBN |
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| Notes |
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Approved |
yes |
| Call Number |
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Serial |
4473 |
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| Author |
Savarino, J
Morin, S
Erbland, J
Patey, M.
Vicars, W.
Alexander, B
Achterberg, E. |
| Title |
Nitrate and its N and O isotopes in a tropical marine boundary layer, Goldschmidt Conference, Firenze, Italy |
Type |
Conference - International - Communication |
| Year |
2013 |
Publication |
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Abbreviated Journal |
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Issue |
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1011 |
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Conference |
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Approved |
yes |
| Call Number |
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Serial |
4701 |
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| Author |
Meusinger, C.
Berhanu, T. A.
Erbland, J
Savarino, J
Johnson, M. S. |
| Title |
Laboratory study of nitrate photolysis in Antarctic snow: Quantum yield, mechanism, isotope effects and wavelength dependence, Goldschmidt Conference, Firenze, Italy |
Type |
Conference - International - Communication |
| Year |
2013 |
Publication |
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Abbreviated Journal |
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| Volume |
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Issue |
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Pages |
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| Keywords |
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| Abstract |
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| Programme |
1011 |
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Approved |
yes |
| Call Number |
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Serial |
4705 |
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| Author |
Berhanu, Tesfaye A.
Meusinger, Carl
Erbland, Joseph
Jost, RĆ©my
Bhattacharya, S. K.
Johnson, Matthew S.
Savarino, Joƫl |
| Title |
Laboratory study of nitrate photolysis in Antarctic snow. II. Isotopic effects and wavelength dependence |
Type |
Journal Article |
| Year |
2014 |
Publication |
The Journal of Chemical Physics |
Abbreviated Journal |
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| Volume |
140 |
Issue |
244306 |
Pages |
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| Keywords |
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| Abstract |
Atmospheric nitrate is preserved in Antarctic snow firn and ice. However, at low snow accumulation sites, post-depositional processes induced by sunlight obscure its interpretation. The goal of these studies (see also Paper I by Meusinger et al. [āLaboratory study of nitrate photolysis in Antarctic snow. I. Observed quantum yield, domain of photolysis, and secondary chemistry,ā J. Chem. Phys. 140, 244305 (2014)]) is to characterize nitrate photochemistry and improve the interpretation of the nitrate ice core record. Naturally occurring stable isotopes in nitrate (15N, 17O, and 18O) provide ad- ditional information concerning post-depositional processes. Here, we present results from studies of the wavelength-dependent isotope effects from photolysis of nitrate in a matrix of natural snow. Snow from Dome C, Antarctica was irradiated in selected wavelength regions using a Xe UV lamp and filters. The irradiated snow was sampled and analyzed for nitrate concentration and isotopic composition (ĆĀ“15N, ĆĀ“18O, and Ć“ĀĀ°ā¬17O). From these measurements an average photolytic isotopic frac- tionation of 15ĆĀµ = (-15 Ā± 1.2)ā° was found for broadband Xe lamp photolysis. These results are due in part to excitation of the intense absorption band of nitrate around 200 nm in addition to the weaker band centered at 305 nm followed by photodissociation. An experiment with a filter blocking wave- lengths shorter than 320 nm, approximating the actinic flux spectrum at Dome C, yielded a photolytic isotopic fractionation of 15ĆĀµ = (-47.9 Ā± 6.8)ā°, in good agreement with fractionations determined by previous studies for the East Antarctic Plateau which range from -40 to -74.3ā°. We describe a new semi-empirical zero point energy shift model used to derive the absorption cross sections of 14NO3- and 15NO3- in snow at a chosen temperature. The nitrogen isotopic fractionations obtained by applying this model under the experimental temperature as well as considering the shift in width and center well reproduced the values obtained in the laboratory study. These cross sections can be used in isotopic models to reproduce the stable isotopic composition of nitrate found in Antarctic snow profiles. |
| Programme |
1011 |
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Series Title |
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Series Issue |
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Edition |
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| ISSN |
0021-9606 |
ISBN |
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Medium |
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Conference |
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| Notes |
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Approved |
yes |
| Call Number |
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Serial |
4917 |
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| Author |
Gallet J-C, Domine F, Savarino J, Dumont M, Brun E, |
| Title |
The growth of sublimation crystals and surface hoar on the Antarctic plateau
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Type |
Journal Article |
| Year |
2014 |
Publication |
The Cryosphere |
Abbreviated Journal |
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| Volume |
8 |
Issue |
4 |
Pages |
1205-1215 |
| Keywords |
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| Abstract |
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| Programme |
1011 |
| Campaign |
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| Address |
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| Corporate Author |
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Thesis |
Bachelor's thesis |
| Publisher |
Copernicus Publications |
Place of Publication |
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Edition |
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| ISSN |
1994-0424 |
ISBN |
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Medium |
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Expedition |
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| Notes |
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Approved |
yes |
| Call Number |
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Serial |
4919 |
| Permanent link to this record |
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| Author |
Meusinger Carl, Berhanu Tesfaye A, Erbland Joseph, Savarino Joel, Johnson Matthew S, |
| Title |
Laboratory study of nitrate photolysis in Antarctic snow. I. Observed quantum yield, domain of photolysis, and secondary chemistry
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Type |
Journal Article |
| Year |
2014 |
Publication |
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Abbreviated Journal |
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| Volume |
140 |
Issue |
24 |
Pages |
244305 |
| Keywords |
ice, snow, geochemistry, |
| Abstract |
Post-depositional processes alter nitrate concentration and nitrate isotopic composition in the top lay- ers of snow at sites with low snow accumulation rates, such as Dome C, Antarctica. Available nitrate ice core records can provide input for studying past atmospheres and climate if such processes are understood. It has been shown that photolysis of nitrate in the snowpack plays a major role in nitrate loss and that the photolysis products have a significant influence on the local troposphere as well as on other species in the snow. Reported quantum yields for the main reaction spans orders of magni- tude ā apparently a result of whether nitrate is located at the air-ice interface or in the ice matrix ā constituting the largest uncertainty in models of snowpack NOx emissions. Here, a laboratory study is presented that uses snow from Dome C and minimizes effects of desorption and recombination by flushing the snow during irradiation with UV light. A selection of UV filters allowed examination of the effects of the 200 and 305 nm absorption bands of nitrate. Nitrate concentration and photon flux were measured in the snow. The quantum yield for loss of nitrate was observed to decrease from 0.44 to 0.003 within what corresponds to days of UV exposure in Antarctica. The superposi- tion of photolysis in two photochemical domains of nitrate in snow is proposed: one of photolabile nitrate, and one of buried nitrate. The difference lies in the ability of reaction products to escape the snow crystal, versus undergoing secondary (recombination) chemistry. Modeled NOx emissions may increase significantly above measured values due to the observed quantum yield in this study. The apparent quantum yield in the 200 nm band was found to be ~1%, much lower than reported for aqueous chemistry. A companion paper presents an analysis of the change in isotopic composition of snowpack nitrate based on the same samples as in this study. |
| Programme |
1011 |
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| Notes |
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Approved |
yes |
| Call Number |
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Serial |
4925 |
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| Author |
Geng Lei, Alexander Becky, Cole-Dai Jihong, Steig Eric J, Savarino Joƫl, Sofen Eric D, Schauer Andrew J, |
| Title |
Nitrogen isotopes in ice core nitrate linked to anthropogenic atmospheric acidity change
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Type |
Journal Article |
| Year |
2014 |
Publication |
Proceedings of the National Academy of Sciences |
Abbreviated Journal |
Proc. Natl. Acad. Sci. U.S.A. |
| Volume |
111 |
Issue |
16 |
Pages |
5808 -5812 |
| Keywords |
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| Abstract |
Nitrogen stable isotope ratio (δ15N) in Greenland snow nitrate and in North American remote lake sediments has decreased gradually beginning as early as ∼1850 Christian Era. This decrease was attributed to increasing atmospheric deposition of anthropogenic nitrate, reflecting an anthropogenic impact on the global nitrogen cycle, and the impact was thought to be amplified ∼1970. However, our subannually resolved ice core records of δ15N and major ions (e.g., Graphic, Graphic) over the last ∼200 y show that the decrease in δ15N is not always associated with increasing Graphic concentrations, and the decreasing trend actually leveled off ∼1970. Correlation of δ15N with H+, Graphic, and HNO3 concentrations, combined with nitrogen isotope fractionation models, suggests that the δ15N decrease from ∼1850ā1970 was mainly caused by an anthropogenic-driven increase in atmospheric acidity through alteration of the gas−particle partitioning of atmospheric nitrate. The concentrations of Graphic and Graphic also leveled off ∼1970, reflecting the effect of air pollution mitigation strategies in North America on anthropogenic NOx and SO2 emissions. The consequent atmospheric acidity change, as reflected in the ice core record of H+ concentrations, is likely responsible for the leveling off of δ15N ∼1970, which, together with the leveling off of Graphic concentrations, suggests a regional mitigation of anthropogenic impact on the nitrogen cycle. Our results highlight the importance of atmospheric processes in controlling δ15N of nitrate and should be considered when using δ15N as a source indicator to study atmospheric flux of nitrate to land surface/ecosystems. |
| Programme |
1011 |
| Campaign |
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| Address |
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| Corporate Author |
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Thesis |
Bachelor's thesis |
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Series Issue |
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Edition |
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| ISSN |
0027-8424 |
ISBN |
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Expedition |
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Conference |
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| Notes |
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Approved |
yes |
| Call Number |
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Serial |
4922 |
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| Author |
Vicars, William C.
Savarino, Joƫl |
| Title |
Quantitative constraints on the 17O-excess (Δ17O) signature of surface ozone: Ambient measurements from 50Ā°N to 50Ā°S using the nitrite-coated filter technique |
Type |
Journal Article |
| Year |
2014 |
Publication |
GEOCHIMICA ET COSMOCHIMICA ACTA |
Abbreviated Journal |
Geochim. Cosmochim. Acta |
| Volume |
135 |
Issue |
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Pages |
270-287 |
| Keywords |
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| Abstract |
The unique and distinctive 17O-excess (D17O) of ozone (O3) provides a conservative tracer for oxidative processes in both modern and paleo-atmospheres and has acted as the primary driver of theoretical and experimental research into non-mass-dependent fractionation (NMDF) for over three decades. However, due to the inherent complexity of extracting O3 from ambient air, the existing observational dataset for tropospheric O3 isotopic composition remains quite small. Recent analytical developments have provided a robust and reliable means for determining D17O(O3)trans., the transferrable D17O signature of ozone in the troposphere (Vicars et al., 2012). We have employed this new methodology in a systematic investigation of the spatial and seasonal features of D17O(O3)trans. in two separate field campaigns: a weekly sampling effort at our laboratory in Grenoble, France (45Ā°N) throughout 2012 (n = 47) and a four-week campaign onboard the Research Vessel (R/V) Polarstern along a latitudinal transect from 50Ā°S to 50Ā°N in the Atlantic Ocean (n = 30). The bulk 17O-excess of ozone, denoted D17O(O3)bulk, exhibited mean (Ā±1r) values of 26.2 Ā± 1.3& (D17O(O3)trans. = 39.3 Ā± 2.0&) and 25.9 Ā± 1.1& (D17O(O3)trans. = 38.8 Ā± 1.6&) for the Grenoble and R/V Polarstern collections, respectively. This range of values is in excellent quantitative agreement with the two previous studies of ozone triple-isotope composition, which have yielded mean (Ā±1r) D17O(O3)bulk values of 25.4 Ā± 9.0& (n = 89). However, the magnitude of variability detected in the present study is much smaller than that formerly reported. In fact, the standard deviation of D17O(O3)bulk in each new dataset is lower than the uncertainty previously estimated for the filter technique (Ā±1.7&), indicating a low level of natural spatial and temporal variation in the 17O-excess of surface ozone. For instance, no clear temporal pattern in D17O(O3) is evident in the annual record from Grenoble despite dramatic seasonal variations in ozone and atmospheric reactive nitrogen (NOx = NO + NO2) concentrations. However, a small but statistically significant difference is distinguishable in the R/V Polarstern record when comparing samples collected in the Southern and Northern Hemispheres, which possessed average D17O(O3)bulk values of 25.2 Ā± 1.0& and 26.5 Ā± 0.7&, respectively. The implications of these results are discussed in the context of the tropospheric ozone budget and the use of oxygen isotope ratios of secondary atmospheric species to derive information regarding oxidation pathways from modern and paleo-atmospheres. |
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1011 |
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| ISSN |
0016-7037 |
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Approved |
yes |
| Call Number |
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Serial |
4926 |
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| Author |
Gautier, E
Savarino, J
Farquhar, J
Erbland, J |
| Title |
A reconstruction of terrestrial volcanism over the last 2500 years using sulfur isotopes in ice-cores, Goldschmidt Conference, Sacramento, USA |
Type |
Conference - International - Poster |
| Year |
2014 |
Publication |
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Abbreviated Journal |
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1011 |
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Approved |
yes |
| Call Number |
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Serial |
4927 |
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| Author |
Vicars William |
| Title |
Constraining the propagation of the 17Oexcess (cap17O) of ozone in the troposphere: Towards a quantitative interpretation of the oxygen isotopic composition of atmospheric nitrate |
Type |
Thesis |
| Year |
2013 |
Publication |
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1011 |
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yes |
| Call Number |
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Serial |
5731 |
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