| Records |
| Author |
Philip Bertrand, Joël Bêty, Nigel G. Yoccoz, Marie-Josée Fortin, Hallvard Strøm, Harald Steen, Jack Kohler, Stephanie M. Harris, Samantha C. Patrick, Olivier Chastel, P. Blévin, Haakon Hop, Geir Moholdt, Joséphine Maton, Sébastien Descamps |
| Title |
Fine-scale spatial segregation in a pelagic seabird driven by differential use of tidewater glacier fronts |
Type |
Journal |
| Year |
2021 |
Publication |
Scientific Reports |
Abbreviated Journal |
|
| Volume |
11 |
Issue |
1 |
Pages |
22109 |
| Keywords |
Behavioural ecology Biogeography |
| Abstract |
In colonially breeding marine predators, individual movements and colonial segregation are influenced by seascape characteristics. Tidewater glacier fronts are important features of the Arctic seascape and are often described as foraging hotspots. Albeit their documented importance for wildlife, little is known about their structuring effect on Arctic predator movements and space use. In this study, we tested the hypothesis that tidewater glacier fronts can influence marine bird foraging patterns and drive spatial segregation among adjacent colonies. We analysed movements of black-legged kittiwakes (Rissa tridactyla) in a glacial fjord by tracking breeding individuals from five colonies. Although breeding kittiwakes were observed to travel up to ca. 280 km from the colony, individuals were more likely to use glacier fronts located closer to their colony and rarely used glacier fronts located farther away than 18 km. Such variation in the use of glacier fronts created fine-scale spatial segregation among the four closest (ca. 7 km distance on average) kittiwake colonies. Overall, our results support the hypothesis that spatially predictable foraging patches like glacier fronts can have strong structuring effects on predator movements and can modulate the magnitude of intercolonial spatial segregation in central-place foragers. |
| Programme |
330 |
| 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 |
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| ISSN |
2045-2322 |
ISBN |
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Medium |
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| Area |
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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 |
8309 |
| Permanent link to this record |
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| Author |
Karine Sellegri, Alessia Nicosia, Evelyn Freney, Julia Uitz, Melilotus Thyssen, Gérald Grégori, Anja Engel, Birthe Zäncker, Nils Haëntjens, Sébastien Mas, David Picard, Alexia Saint-Macary, Maija Peltola, Clémence Rose, Jonathan Trueblood, Dominique Lefevre, Barbara D’Anna, Karine Desboeufs, Nicholas Meskhidze, Cécile Guieu, Cliff S. Law |
| Title |
Surface ocean microbiota determine cloud precursors |
Type |
Journal |
| Year |
2021 |
Publication |
Scientific Reports |
Abbreviated Journal |
|
| Volume |
11 |
Issue |
1 |
Pages |
281 |
| Keywords |
Atmospheric science Marine biology |
| Abstract |
One pathway by which the oceans influence climate is via the emission of sea spray that may subsequently influence cloud properties. Sea spray emissions are known to be dependent on atmospheric and oceanic physicochemical parameters, but the potential role of ocean biology on sea spray fluxes remains poorly characterized. Here we show a consistent significant relationship between seawater nanophytoplankton cell abundances and sea-spray derived Cloud Condensation Nuclei (CCN) number fluxes, generated using water from three different oceanic regions. This sensitivity of CCN number fluxes to ocean biology is currently unaccounted for in climate models yet our measurements indicate that it influences fluxes by more than one order of magnitude over the range of phytoplankton investigated. |
| Programme |
1187 |
| 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 |
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| ISSN |
2045-2322 |
ISBN |
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Medium |
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| Area |
|
Expedition |
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Conference |
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| Notes |
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Approved |
yes |
| Call Number |
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Serial |
7264 |
| Permanent link to this record |
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| Author |
Emilia Trudnowska, Léo Lacour, Mathieu Ardyna, Andreas Rogge, Jean Olivier Irisson, Anya M. Waite, Marcel Babin, Lars Stemmann |
| Title |
Marine snow morphology illuminates the evolution of phytoplankton blooms and determines their subsequent vertical export |
Type |
Journal |
| Year |
2021 |
Publication |
Nature Communications |
Abbreviated Journal |
|
| Volume |
12 |
Issue |
1 |
Pages |
2816 |
| Keywords |
Carbon cycle Marine biology |
| Abstract |
The organic carbon produced in the ocean’s surface by phytoplankton is either passed through the food web or exported to the ocean interior as marine snow. The rate and efficiency of such vertical export strongly depend on the size, structure and shape of individual particles, but apart from size, other morphological properties are still not quantitatively monitored. With the growing number of in situ imaging technologies, there is now a great possibility to analyze the morphology of individual marine snow. Thus, automated methods for their classification are urgently needed. Consequently, here we present a simple, objective categorization method of marine snow into a few ecologically meaningful functional morphotypes using field data from successive phases of the Arctic phytoplankton bloom. The proposed approach is a promising tool for future studies aiming to integrate the diversity, composition and morphology of marine snow into our understanding of the biological carbon pump. |
| Programme |
1164 |
| 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 |
|
Series Issue |
|
Edition |
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| ISSN |
2041-1723 |
ISBN |
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Medium |
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| Area |
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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 |
8250 |
| Permanent link to this record |
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| Author |
Benjamin Pohl, Vincent Favier, Jonathan Wille, Danielle G Udy, Tessa R Vance, Julien Pergaud, Niels Dutrievoz, Juliette Blanchet, Christoph Kittel, Charles Amory, Gerhard Krinner, Francis Codron |
| Title |
Relationship Between Weather Regimes and Atmospheric Rivers in East Antarctica |
Type |
Journal |
| Year |
2021 |
Publication |
Journal of Geophysical Research: Atmospheres |
Abbreviated Journal |
|
| Volume |
126 |
Issue |
24 |
Pages |
e2021JD035294 |
| Keywords |
atmospheric rivers East Antarctica snowfall amounts temperature anomalies weather regimes |
| Abstract |
Here, we define weather regimes in the East Antarctica—Southern Ocean sector based on daily anomalies of 700 hPa geopotential height derived from ERA5 reanalysis during 1979–2018. Most regimes and their preferred transitions depict synoptic-scale disturbances propagating eastwards off the Antarctic coastline. While regime sequences are generally short, their interannual variability is strongly driven by the polarity of the Southern Annular Mode (SAM). Regime occurrences are then intersected with atmospheric rivers (ARs) detected over the same region and period. ARs are equiprobable throughout the year, but clearly concentrate during regimes associated with a strong atmospheric ridges/blockings on the eastern part of the domain, which act to channel meridional advection of heat and moisture from the lower latitudes towards Antarctica. Both regimes and ARs significantly shape climate variability in Antarctica. Regimes favorable to AR occurrences are associated with anomalously warm and humid conditions in coastal Antarctica and, to a lesser extent, the hinterland parts of the Antarctic plateau. These anomalies are strongly enhanced during AR events, with warmer anomalies and dramatically amplified snowfall amounts. Large-scale conditions favoring AR development are finally explored. They show weak dependency to the SAM, but particularly strong atmospheric ridges/blockings over the Southern Ocean appear as the most favorable pattern, in which ARs can be embedded, and to which they contribute. |
| Programme |
411 |
| 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 |
2169-8996 |
ISBN |
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Medium |
|
| Area |
|
Expedition |
|
Conference |
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| Notes |
|
Approved |
yes |
| Call Number |
|
Serial |
8430 |
| Permanent link to this record |
| |
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| |
| Author |
A. Barbero, J. Savarino, R. Grilli, C. Blouzon, G. Picard, M. M. Frey, Y. Huang, N. Caillon |
| Title |
New Estimation of the NOx Snow-Source on the Antarctic Plateau |
Type |
Journal |
| Year |
2021 |
Publication |
Journal of Geophysical Research: Atmospheres |
Abbreviated Journal |
|
| Volume |
126 |
Issue |
20 |
Pages |
e2021JD035062 |
| Keywords |
Antarctic Plateau flux chamber nitrate photolysis snowpack emissions |
| Abstract |
To fully decipher the role of nitrate photolysis on the atmospheric oxidative capacity in snow-covered regions, NOx flux must be determined with more precision than existing estimates. Here, we introduce a method based on dynamic flux chamber measurements for evaluating the NOx production by photolysis of snowpack nitrate in Antarctica. Flux chamber experiments were conducted for the first time in Antarctica, at the French-Italian station Concordia, Dome C (75°06'S, 123°20’E, 3233 m a.s.l) during the 2019–2020 summer campaign. Measurements were gathered with several snow samples of different ages ranging from newly formed drifted snow to 6-year-old firn. Contrary to existing literature expectations, the daily average photolysis rate coefficient, , did not significantly vary between differently aged snow samples, suggesting that the photolabile nitrate in snow behaves as a single-family source with common photochemical properties, where a = (2.37 0.35) × 10−8 s−1 (1) has been calculated from December 10th 2019 to January 7th 2020. At Dome C summer daily average NOx flux, , based on measured NOx production rates was estimated to be (4.3 1.2) × 108 molecules cm−2 s−1, which is 1.5–7 times less than the net NOx flux observed previously above snow at Dome C using the gradient flux method. Using these results, we extrapolated an annual continental snow sourced NOx budget of 0.017 0.003 TgN y−1, 2 times the nitrogen budget, (N-budget), of the stratospheric denitrification previously estimated for Antarctica. These quantifications of nitrate photolysis using flux chamber experiments provide a road-map toward a new parameterization of the product that can improve future global and regional models of atmospheric chemistry. |
| Programme |
1177 |
| 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 |
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| ISSN |
2169-8996 |
ISBN |
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Medium |
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| Area |
|
Expedition |
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Conference |
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| Notes |
|
Approved |
yes |
| Call Number |
|
Serial |
8393 |
| Permanent link to this record |
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| |
| Author |
Ryo Okuwaki, Stephen P. Hicks, Timothy J. Craig, Wenyuan Fan, Saskia Goes, Tim J. Wright, Yuji Yagi |
| Title |
Illuminating a Contorted Slab With a Complex Intraslab Rupture Evolution During the 2021 Mw 7.3 East Cape, New Zealand Earthquake |
Type |
Journal |
| Year |
2021 |
Publication |
Geophysical Research Letters |
Abbreviated Journal |
|
| Volume |
48 |
Issue |
24 |
Pages |
e2021GL095117 |
| Keywords |
earthquake rupture finite-fault inversion Hikurangi intraslab earthquakes slab geometry source imaging |
| Abstract |
The state-of-stress within subducting oceanic plates controls rupture processes of deep intraslab earthquakes. However, little is known about how the large-scale plate geometry and the stress regime relate to the physical nature of the deep intraslab earthquakes. Here we find, by using globally and locally observed seismic records, that the moment magnitude 7.3 2021 East Cape, New Zealand earthquake was driven by a combination of shallow trench-normal extension and unexpectedly, deep trench-parallel compression. We find multiple rupture episodes comprising a mixture of reverse, strike-slip, and normal faulting. Reverse faulting due to the trench-parallel compression is unexpected given the apparent subduction direction, so we require a differential buoyancy-driven stress rotation, which contorts the slab near the edge of the Hikurangi plateau. Our finding highlights that buoyant features in subducting plates may cause diverse rupture behavior of intraslab earthquakes due to the resulting heterogeneous stress state within slabs. |
| Programme |
133 |
| 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 |
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| ISSN |
1944-8007 |
ISBN |
|
Medium |
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| Area |
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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 |
8313 |
| Permanent link to this record |
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| Author |
Mathieu Casado, Amaelle Landais, Ghislain Picard, Laurent Arnaud, Giuliano Dreossi, Barbara Stenni, Frederic Prié |
| Title |
Water Isotopic Signature of Surface Snow Metamorphism in Antarctica |
Type |
Journal |
| Year |
2021 |
Publication |
Geophysical Research Letters |
Abbreviated Journal |
|
| Volume |
48 |
Issue |
17 |
Pages |
e2021GL093382 |
| Keywords |
excess Ice cores metamorhism Paleoclimate water isotopes |
| Abstract |
Water isotope ratios of ice cores are a key source of information on past temperatures. Through fractionation within the hydrological cycle, temperature is imprinted in the water isotopic composition of snowfalls. However, this signal of climatic interest is modified after deposition when snow remains at the surface exposed to the atmosphere. Comparing time series of surface snow isotopic composition at Dome C with satellite observations of surface snow metamorphism, we found that long summer periods without precipitation favor surface snow metamorphism altering the surface snow isotopic composition. Using excess parameters (combining D,17O, and 18O fractions) allow the identification of this alteration caused by sublimation and condensation of surface hoar. The combined measurement of all three isotopic compositions could help identifying ice core sections influenced by snow metamorphism in sites with very low snow accumulation. |
| Programme |
1110 |
| 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 |
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| ISSN |
1944-8007 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
|
Approved |
yes |
| Call Number |
|
Serial |
8306 |
| Permanent link to this record |
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| Author |
M. Legrand, R. Weller, S. Preunkert, B. Jourdain |
| Title |
Ammonium in Antarctic Aerosol: Marine Biological Activity Versus Long-Range Transport of Biomass Burning |
Type |
Journal |
| Year |
2021 |
Publication |
Geophysical Research Letters |
Abbreviated Journal |
|
| Volume |
48 |
Issue |
11 |
Pages |
e2021GL092826 |
| Keywords |
aerosol black carbon ammonium Antarctic biomass burning et marine biota oxalate potassium |
| Abstract |
Year-round records of the ionic composition of Antarctic aerosol were obtained at the inland Dome C (DC) and coastal Neumayer (NM) sites, with additional observations of black carbon (BC) at NM. Discussions focus on the origin of ammonium in Antarctica. This first Antarctic atmospheric study of several species emitted by biomass burning (BB) indicates that BC and oxalate reach a maximum in October in relation to BB activity in the southern hemisphere. Ammonium reaches a maximum 2 months later, suggesting that BB remains a minor ammonium source there. The ammonium maximum in December coincides with the occurrence of diatom blooms in the austral ocean, suggesting that oceanic ammonia emissions are the main source of ammonium in Antarctica. The ammonium to sulfur-derived biogenic species molar ratio of 0.15 in summer suggests far lower ammonia emissions from the Antarctic oceans than midlatitude southern oceans. |
| Programme |
903 |
| 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 |
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| ISSN |
1944-8007 |
ISBN |
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Medium |
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| Area |
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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 |
8252 |
| Permanent link to this record |
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| Author |
G. Hubert, S. Aubry |
| Title |
Study of the Impact of Past Extreme Solar Events on the Modern Air Traffic |
Type |
Journal |
| Year |
2021 |
Publication |
Space Weather |
Abbreviated Journal |
|
| Volume |
19 |
Issue |
4 |
Pages |
e2020SW002665 |
| Keywords |
|
| Abstract |
The ancient solar energetic particle (SEP) events of 774/775 CE and 993/994 CE were characterized thanks to radionuclide productions stored in environmental archives as ice cores or tree rings. Primary cosmic ray spectra deduced from these cosmogenic isotope data indicate that the impact of these extreme SEP events would have been much more significant than any of the ones observed during the modern era. However, the impact of these should be studied more accurately in the framework of the ambient dose equivalent impacting aircrew and passengers in the air traffic context by considering physical parameters such as time profile or anisotropy properties. In this study, the impact that 774/775 CE and 993/994 CE past extreme SEP events could have had on modern air traffic is discussed. Possible event spectra for these ancient events are derived from the spectra ground-level enhancement (GLE) 5 and GLE 69, which have been observed during the modern era and have been widely studied/characterized using measurements. The investigations include the impact of the SEP activity on ambient dose equivalent, including detailed analyses considering route, airplane characteristics (departure, arrival, continent, airplane type), and the time occurrence of the SEP event. Statistical analyses show that additional dose levels can reach values on the order of 70 mSv, which is absolutely significant considering the current air traffic recommendations. The orders of magnitude of the ambient dose equivalent induced during past extreme SEP events raises a number of issues, both for aircrews and for avionics hardware. This study demonstrates that simulations can be useful for the evaluation of risks in case of extreme SEP events. |
| Programme |
1112 |
| 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 |
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| ISSN |
1542-7390 |
ISBN |
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Medium |
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| Area |
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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 |
7934 |
| Permanent link to this record |
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| Author |
Steven Franke, Daniela Jansen, Sebastian Beyer, Niklas Neckel, Tobias Binder, John Paden, Olaf Eisen |
| Title |
Complex Basal Conditions and Their Influence on Ice Flow at the Onset of the Northeast Greenland Ice Stream |
Type |
Journal |
| Year |
2021 |
Publication |
Journal of Geophysical Research: Earth Surface |
Abbreviated Journal |
|
| Volume |
126 |
Issue |
3 |
Pages |
e2020JF005689 |
| Keywords |
basal roughness bed conditions Greenland Ice Sheet ice stream Northeast Greenland Ice Stream radio-echo sounding |
| Abstract |
Abstract The ice stream geometry and large ice surface velocities at the onset region of the Northeast Greenland Ice Stream (NEGIS) are not yet well reproduced by ice sheet models. The quantification of basal sliding and a parametrization of basal conditions remains a major gap. In this study, we assess the basal conditions of the onset region of the NEGIS in a systematic analysis of airborne ultra-wideband radar data. We evaluate basal roughness and basal return echoes in the context of the current ice stream geometry and ice surface velocity. We observe a change from a smooth to a rougher bed where the ice stream widens, and a distinct roughness anisotropy, indicating a preferred orientation of subglacial structures. In the upstream region, the excess ice mass flux through the shear margins is evacuated by ice flow acceleration and along-flow stretching of the ice. At the downstream part, the generally rougher bed topography correlates with a decrease in flow acceleration and lateral variations in ice surface velocity. Together with basal water routing pathways, this hints to two different zones in this part of the NEGIS: the upstream region collecting water, with a reduced basal traction, and downstream, where the ice stream is slowing down and is widening on a rougher bed, with a distribution of basal water toward the shear margins. Our findings support the hypothesis that the NEGIS is strongly interconnected to the subglacial water system in its onset region, but also to the subglacial substrate and morphology. |
| Programme |
1180 |
| 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 |
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| ISSN |
2169-9003 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
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Approved |
yes |
| Call Number |
|
Serial |
7272 |
| Permanent link to this record |
