| Records |
| 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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| Publisher |
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Place of Publication |
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| 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 |
|
Expedition |
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Conference |
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| Notes |
|
Approved |
yes |
| Call Number |
|
Serial |
8313 |
| Permanent link to this record |
| |
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| |
| Author |
Weisen Shen, Douglas A. Wiens, Andrew J. Lloyd, Andrew A. Nyblade |
| Title |
A Geothermal Heat Flux Map of Antarctica Empirically Constrained by Seismic Structure |
Type |
Journal |
| Year |
2020 |
Publication |
Geophysical Research Letters |
Abbreviated Journal |
|
| Volume |
47 |
Issue |
14 |
Pages |
e2020GL086955 |
| Keywords |
Antarctica crust and uppermost mantle geothermal heat flux ice sheet modeling |
| Abstract |
The geothermal heat flux (GHF) is an important boundary condition for modeling the movement of the Antarctic ice sheet but is difficult to measure systematically at a continental scale. Earlier GHF maps suffer from low resolution and possibly biased assumptions in tectonism and crustal heat generation, resulting in significant uncertainty. We present a new GHF map for Antarctica constructed by empirically relating the upper mantle structure to known GHF in the continental United States. The new map, compared with previously seismologically determined one, has improved resolution and lower uncertainties. New features in this map include high GHF in the southern Transantarctic Mountains where warmer uppermost mantle is introduced by lithospheric removal and in the Thwaites Glacier region. Additionally, a modest GHF in the central West Antarctic Rift system near the Siple Coast and an absence of large-scale regions with GHF greater than 90 mW/m2 are found. |
| 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 |
|
| Area |
|
Expedition |
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Conference |
|
| Notes |
|
Approved |
yes |
| Call Number |
|
Serial |
7887 |
| 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 |
|
Expedition |
|
Conference |
|
| Notes |
|
Approved |
yes |
| Call Number |
|
Serial |
8252 |
| Permanent link to this record |
| |
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| |
| Author |
Anais J. Orsi, Kenji Kawamura, Valerie Masson-Delmotte, Xavier Fettweis, Jason E. Box, Dorthe Dahl-Jensen, Gary D. Clow, Amaelle Landais, Jeffrey P. Severinghaus |
| Title |
The recent warming trend in North Greenland |
Type |
Journal |
| Year |
2017 |
Publication |
Geophysical Research Letters |
Abbreviated Journal |
|
| Volume |
44 |
Issue |
12 |
Pages |
6235-6243 |
| Keywords |
borehole temperature Greenland ice sheet surface warming |
| Abstract |
|
| Programme |
458 |
| Campaign |
|
| Address |
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| Corporate Author |
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Thesis |
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| Publisher |
|
Place of Publication |
|
Editor |
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| Language |
|
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 |
1944-8007 |
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
|
Approved |
yes |
| Call Number |
|
Serial |
8273 |
| Permanent link to this record |
| |
|
| |
| Author |
|
| 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 |
|
Edition |
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| ISSN |
1944-8007 |
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
|
Approved |
yes |
| Call Number |
|
Serial |
8306 |
| Permanent link to this record |
| |
|
| |
| Author |
Piero Poli, Nikolai M. Shapiro |
| Title |
|
Type |
Journal |
| Year |
2022 |
Publication |
Geophysical Research Letters |
Abbreviated Journal |
|
| Volume |
49 |
Issue |
8 |
Pages |
e2022GL098123 |
| Keywords |
backprojection seismology source surface waves Tonga volcanology |
| Abstract |
|
| 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 |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
|
Approved |
yes |
| Call Number |
|
Serial |
8458 |
| Permanent link to this record |
| |
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| |
| Author |
Alison F. Banwell, Nander Wever, Devon Dunmire, Ghislain Picard |
| Title |
Quantifying Antarctic-Wide Ice-Shelf Surface Melt Volume Using Microwave and Firn Model Data: 1980 to 2021 |
Type |
Journal |
| Year |
2023 |
Publication |
Geophysical Research Letters |
Abbreviated Journal |
|
| Volume |
50 |
Issue |
12 |
Pages |
e2023GL102744 |
| Keywords |
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| Abstract |
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| 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 |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
|
Approved |
yes |
| Call Number |
|
Serial |
8637 |
| Permanent link to this record |
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| |
| Author |
O. I. Berngardt, J.-P. St- Maurice, J. M. Ruohoniemi, A. Marchaudon |
| Title |
|
Type |
Journal |
| Year |
2022 |
Publication |
Radio Science |
Abbreviated Journal |
|
| Volume |
57 |
Issue |
9 |
Pages |
e2021RS007338 |
| Keywords |
HF radars ionospheric absorption noise quiet-day curve radiowave propagation |
| Abstract |
Based on ray tracing in a smooth ionosphere described by the IRI-2012 model we have inferred the seasonal-diurnal dynamics of radio noise observed by four mid-latitude high-frequency (HF) radars. In the calculations, noise is assumed to be homogeneous and stationary, but the main contribution comes from the radar skip zone boundary due to focusing radiowaves effect. Noise absorption along the ray path is simulated from the IRI-2012 electron density, and from the molecular nitrogen density and electron temperatures obtained from the NRLMSISE-00 model. Earth magnetic field is not taken into account both in the absorption and ray-tracing calculations due to insufficient accuracy of the ionospheric model. The model results are compared with experimental radar data, and good agreement between the two is demonstrated. It is shown that experimentally observed seasonal and diurnal dynamics of the noise correlates well with model predictions. We demonstrated saturation effect at low noise levels. The model makes it possible to estimate the amount of absorption in D- and E-layers using noise observations at SuperDARN and SuperDARN-like poleward-oriented radars, especially at mid-latitudes. This is important for the retrieval of long term variations in the electron density in the lower ionosphere, by using wide coverage provided by these radars' network. The model also makes it feasible to interpret vertical absorption by experimental noise observations, thereby significantly expanding the capability of HF radars to monitor the lower ionosphere, and to provide data for joint analysis with other data, obtained by these radars at E- and F-layer heights. |
| Programme |
312 |
| 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 |
|
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 |
1944-799X |
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
|
Approved |
yes |
| Call Number |
|
Serial |
8075 |
| Permanent link to this record |
| |
|
| |
| Author |
|
| Title |
Ethnoarchaeology of Fuel Use in Northern Forests: Towards a Better Characterization of Prehistoric Fire-Related Activities |
Type |
Journal |
| Year |
2018 |
Publication |
Ethnoarchaeology |
Abbreviated Journal |
|
| Volume |
10 |
Issue |
2 |
Pages |
99-120 |
| Keywords |
Ethnoarchaeology ethnobotany fuel use North America Siberia |
| Abstract |
Prehistoric fuel management and hearth functions are key research issues that have benefitted from the development of experimental and ethnoarchaeogical approaches aimed at providing interpretative models for archaeological fire and fuel studies.In this paper, we present a selection of ethnographic, ethnoarchaeological and ethnohistorical data mostly collected among Evenks and Athabascans of East Siberia and North America. Our aim is to question and discuss the relationship between fuel and hearth functions from an ethnoarchaeobotanical perspective: what are the criteria for selecting plant fuels? How archaeologically visible can these diverse fuel types be and what do they tell us about past fire-related activities?Our data shows that the contents of combustion structures result from multiple people-environment interactions at different levels, few of which are accessible to the archaeologist. Nevertheless, ethnoarchaeology, by fostering a reflection on taphonomy issues in the broad sense, actively contributes to methodological developments leading to a better understanding of complex technical fire-related processes. |
| Programme |
1140 |
| Campaign |
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| Address |
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| Corporate Author |
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Thesis |
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| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
|
Summary Language |
|
Original Title |
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| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
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| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
1944-2890 |
ISBN |
1944-2890 |
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
|
Approved |
yes |
| Call Number |
|
Serial |
7239 |
| Permanent link to this record |
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| |
| Author |
|
| Title |
Modeling the Dynamics of the Atmospheric Boundary Layer Over the Antarctic Plateau With a General Circulation Model |
Type |
Journal |
| Year |
2017 |
Publication |
Journal of Advances in Modeling Earth Systems |
Abbreviated Journal |
|
| Volume |
10 |
Issue |
1 |
Pages |
98-125 |
| Keywords |
Antarctic Plateau boundary-layer general circulation model LMDZ stable boundary-layer regimes |
| Abstract |
Abstract Observations evidence extremely stable boundary layers (SBL) over the Antarctic Plateau and sharp regime transitions between weakly and very stable conditions. Representing such features is a challenge for climate models. This study assesses the modeling of the dynamics of the boundary layer over the Antarctic Plateau in the LMDZ general circulation model. It uses 1 year simulations with a stretched-grid over Dome C. The model is nudged with reanalyses outside of the Dome C region such as simulations can be directly compared to in situ observations. We underline the critical role of the downward longwave radiation for modeling the surface temperature. LMDZ reasonably represents the near-surface seasonal profiles of wind and temperature but strong temperature inversions are degraded by enhanced turbulent mixing formulations. Unlike ERA-Interim reanalyses, LMDZ reproduces two SBL regimes and the regime transition, with a sudden increase in the near-surface inversion with decreasing wind speed. The sharpness of the transition depends on the stability function used for calculating the surface drag coefficient. Moreover, using a refined vertical grid leads to a better reversed ?S-shaped? relationship between the inversion and the wind. Sudden warming events associated to synoptic advections of warm and moist air are also well reproduced. Near-surface supersaturation with respect to ice is not allowed in LMDZ but the impact on the SBL structure is moderate. Finally, climate simulations with the free model show that the recommended configuration leads to stronger inversions and winds over the ice-sheet. However, the near-surface wind remains underestimated over the slopes of East-Antarctica. |
| Programme |
1013 |
| 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 |
|
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 |
1942-2466 |
ISBN |
1942-2466 |
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
|
Approved |
yes |
| Call Number |
|
Serial |
7195 |
| Permanent link to this record |
