| |
Records |
Links |
|
Author |
Debayle, E.; Sambridge, M. |
|
| |
Title |
Inversion of massive surface wave data sets: Model construction and resolution assessment |
Type |
Journal Article |
| |
Year |
2004 |
Publication |
Journal of geophysical research-atmospheres |
Abbreviated Journal |
J. Geophys. Res. |
|
| |
Volume |
109 |
Issue |
|
Pages |
B02316 |
|
| |
Keywords |
7218 Seismology: Lithosphere and upper mantle; 7255 Seismology: Surface waves and free oscillations; 7260 Seismology: Theory and modeling; 8180 Tectonophysics: Tomography |
|
| |
Abstract |
A new scheme is proposed for the inversion of surface waves using a continuous formulation of the inverse problem and the least squares criterion. Like some earlier schemes a Gaussian a priori covariance function controls the horizontal degree of smoothing in the inverted model, which minimizes some artifacts observed with spherical harmonic parameterizations. Unlike earlier schemes the new approach incorporates some sophisticated geometrical algorithms which dramatically increase computational efficiency and render possible the inversion of several tens of thousands of seismograms in few hours on a typical workstation. The new algorithm is also highly suited to parallelization which makes practical the inversion of data sets with more than 50,000 ray paths. The constraint on structural and anisotropic parameters is assessed using a new geometric approach based on Voronoi diagrams, polygonal cells covering the Earth's surface. The size of the Voronoi cells is used to give an indication of the length scale of the structures that can be resolved, while their shape provides information on the variation of azimuthal resolution. The efficiency of the scheme is illustrated with realistic uneven ray path configurations. A preliminary global tomographic model has been built for SV wave heterogeneities and azimuthal variations through the inversion of 24,124 fundamental and higher-mode Rayleigh waveforms. Our results suggest that the use of relatively short paths (<10,000 km) in a global inversion should minimize multipathing, or focusing/defocusing effects and provide lateral resolution of a few hundred kilometers across the globe. |
|
| |
Programme |
133;906 |
|
| |
Campaign |
|
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
American Geophysical Union |
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Summary Language |
|
Original Title |
|
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0148-0227 |
ISBN |
|
Medium |
|
|
| |
Area |
|
Expedition |
|
Conference |
|
|
| |
Notes |
|
Approved |
yes |
|
| |
Call Number  |
IPEV @ Thierry.Lemaire @ |
Serial |
5607 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Le Bohec, C.; Durant, J.M.; Gauthier-Clerc, M.; Stenseth, N.C.; Park, Y.-H.; Pradel, R.; Grémillet, D.; Gendner, J.-P.; Le Maho, Y. |
|
| |
Title |
King penguin population threatened by Southern Ocean warming |
Type |
Journal Article |
| |
Year |
2008 |
Publication |
Proceedings of the National Academy of Sciences |
Abbreviated Journal |
|
|
| |
Volume |
105 |
Issue |
7 |
Pages |
2493-2497 |
|
| |
Keywords |
|
|
| |
Abstract |
Seabirds are sensitive indicators of changes in marine ecosystems and might integrate and/or amplify the effects of climate forcing on lower levels in food chains. Current knowledge on the impact of climate changes on penguins is primarily based on Antarctic birds identified by using flipper bands. Although flipper bands have helped to answer many questions about penguin biology, they were shown in some penguin species to have a detrimental effect. Here, we present for a Subantarctic species, king penguin (), reliable results on the effect of climate on survival and breeding based on unbanded birds but instead marked by subcutaneous electronic tags. We show that warm events negatively affect both breeding success and adult survival of this seabird. However, the observed effect is complex because it affects penguins at several spatio/temporal levels. Breeding reveals an immediate response to forcing during warm phases of El Niño Southern Oscillation affecting food availability close to the colony. Conversely, adult survival decreases with a remote sea-surface temperature forcing (i.e., a 2-year lag warming taking place at the northern boundary of pack ice, their winter foraging place). We suggest that this time lag may be explained by the delay between the recruitment and abundance of their prey, adjusted to the particular 1-year breeding cycle of the king penguin. The derived population dynamic model suggests a 9% decline in adult survival for a 0.26°C warming. Our findings suggest that king penguin populations are at heavy extinction risk under the current global warming predictions. |
|
| |
Programme |
109;137 |
|
| |
Campaign |
|
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
Bachelor's thesis |
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Summary Language |
|
Original Title |
|
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0027-8424 |
ISBN |
|
Medium |
|
|
| |
Area |
|
Expedition |
|
Conference |
|
|
| |
Notes |
10.1073/pnas.0712031105 |
Approved |
yes |
|
| |
Call Number |
IPEV @ Thierry.Lemaire @ |
Serial |
5573 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Whinam, J.; Copson, G.; Chapuis, J.-L. |
|
| |
Title |
Subantarctic Terrestrial Conservation and Management |
Type |
Book Chapter |
| |
Year |
2006 |
Publication |
Trends in Antarctic Terrestrial and Limnetic Ecosystems |
Abbreviated Journal |
|
|
| |
Volume |
|
Issue |
|
Pages |
297-316 |
|
| |
Keywords |
|
|
| |
Abstract |
|
|
| |
Programme |
136 |
|
| |
Campaign |
|
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Summary Language |
|
Original Title |
|
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
|
ISBN |
|
Medium |
|
|
| |
Area |
|
Expedition |
|
Conference |
|
|
| |
Notes |
|
Approved |
yes |
|
| |
Call Number |
IPEV @ Thierry.Lemaire @ |
Serial |
5564 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Rousseau, D.-D.; Duzer, D.; Etienne, J.-L.; Cambon, G.; Jolly, D.; Ferrier, J.; Schevin, P. |
|
| |
Title |
Pollen record of rapidly changing air trajectories to the North Pole |
Type |
Journal Article |
| |
Year |
2004 |
Publication |
Journal of geophysical research-atmospheres |
Abbreviated Journal |
J. Geophys. Res. |
|
| |
Volume |
109 |
Issue |
|
Pages |
|
|
| |
Keywords |
0305 Atmospheric Composition and Structure: Aerosols and particles; 0315 Atmospheric Composition and Structure: Biosphere/atmosphere interactions; 1620 Global Change: Climate dynamics; 3322 Meteorology and Atmospheric Dynamics: Land/atmosphere interactions |
|
| |
Abstract |
Tracing modern atmospheric dynamics is important for constraining models used in past climate reconstruction. However, these models must be verified by modern observations. We present the rapid changeover of two different air trajectories to the North Pole determined by studying the long distance transport of pollen. Samples were collected on a manned floating capsule drifting southward on the sea ice from the North Pole in 2002. It was observed that an air mass at 3000 m altitude transported birch and pine pollen released in Western Europe during week 22 (May 27). Two weeks later, during week 24 (June 10), alder, birch and willow pollen from eastern Siberia reached the drifting station with an air mass at 1000 m altitude. These particular patterns support independent investigations of air trajectories in the Arctic, especially the transport of anthropogenic pollutants such as sulfate and nitrate. |
|
| |
Programme |
349 |
|
| |
Campaign |
|
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
American Geophysical Union |
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Summary Language |
|
Original Title |
|
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0148-0227 |
ISBN |
|
Medium |
|
|
| |
Area |
|
Expedition |
|
Conference |
|
|
| |
Notes |
|
Approved |
yes |
|
| |
Call Number |
IPEV @ Thierry.Lemaire @ |
Serial |
5621 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Magand, O.; Picard, G.; Brucker, L.; Fily, M.; Genthon, C. |
|
| |
Title |
Snow melting bias in microwave mapping of Antarctic snow accumulation |
Type |
Journal Article |
| |
Year |
2008 |
Publication |
The Cryosphere Discuss. |
Abbreviated Journal |
TCD |
|
| |
Volume |
2 |
Issue |
2 |
Pages |
255-273 |
|
| |
Keywords |
|
|
| |
Abstract |
|
|
| |
Programme |
454 |
|
| |
Campaign |
|
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
Copernicus Publications |
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Summary Language |
|
Original Title |
|
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
1994-0432 |
ISBN |
|
Medium |
|
|
| |
Area |
|
Expedition |
|
Conference |
|
|
| |
Notes |
|
Approved |
yes |
|
| |
Call Number |
IPEV @ Thierry.Lemaire @ |
Serial |
5505 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Genthon, C.; Cosme, E. |
|
| |
Title |
Intermittent signature of ENSO in west-Antarctic precipitation |
Type |
Journal Article |
| |
Year |
2003 |
Publication |
Geophysical research letters |
Abbreviated Journal |
|
|
| |
Volume |
30 |
Issue |
|
Pages |
|
|
| |
Keywords |
3349 Meteorology and Atmospheric Dynamics: Polar meteorology; 3354 Meteorology and Atmospheric Dynamics: Precipitation; 1620 Global Change: Climate dynamics; 1655 Global Change: Water cycles; 9310 Information Related to Geographic Region: Antarctica |
|
| |
Abstract |
Precipitation data from the new ERA40 reanalyses and from a 200-year simulation confirm a robust main mode of precipitation variability in west Antarctica. An intermittently strong ENSO signature is found in this mode. However, high correlation with ENSO indices appears infrequent. Thus, the high correlation found in ERA40, and previously in other chronologically realistic data, in the late 1980s and the 1990s may not be expected to last. Unlike previously suggested by others, the sign of the correlation between ENSO indices and west Antarctic precipitation, when significant, does not appear to change in time: Precipitation variability at the ENSO pace in the Bellingshausen-Weddell (Ross-Amunsden) region is consistently in phase (phase opposition, respectively) with the Southern Oscillation Index. This is consistent with a tropospheric wave train connecting the tropical Pacific and west Antarctic regions, which modulates in phase opposition the advection of air and moisture in the 2 regions. |
|
| |
Programme |
411 |
|
| |
Campaign |
|
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
American Geophysical Union |
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Summary Language |
|
Original Title |
|
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0094-8276 |
ISBN |
|
Medium |
|
|
| |
Area |
|
Expedition |
|
Conference |
|
|
| |
Notes |
|
Approved |
yes |
|
| |
Call Number |
IPEV @ Thierry.Lemaire @ |
Serial |
5605 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Domine, F.; Taillandier, A.S.; Simpson, W.R.; Severin, K. |
|
| |
Title |
Specific surface area, density and microstructure of frost flowers |
Type |
Journal Article |
| |
Year |
2005 |
Publication |
Geophysical research letters |
Abbreviated Journal |
|
|
| |
Volume |
32 |
Issue |
|
Pages |
|
|
| |
Keywords |
0736 Cryosphere: Snow; 0750 Cryosphere: Sea ice; 0754 Cryosphere: Leads |
|
| |
Abstract |
Frost flowers often grow on new sea ice. They are thought to have a high specific surface area (SSA) that provides sites for heterogeneous reactions. We have measured the SSA of frost flowers using CH4 adsorption at 77 K and obtained a value of 185 (+80 ?50) cm2/g, much lower than inferred by others. Their density is 0.02 g/cm3. We calculate that the total surface area of frost flowers is 1.4 m2 per m2 of ice surface, so that they do not increase the ice surface area significantly. Their role as sites for enhanced heterogeneous reactions should be reconsidered. Frost flowers also commonly grow on fresh water and the saline brine seen on young sea ice is not necessary for their growth. Photo- and electro-micrographs reveal hollow and concave structures, typical of very fast growing crystals. The brine that wicks up frost flowers considerably perturbs their growth. |
|
| |
Programme |
437 |
|
| |
Campaign |
|
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
American Geophysical Union |
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Summary Language |
|
Original Title |
|
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0094-8276 |
ISBN |
|
Medium |
|
|
| |
Area |
|
Expedition |
|
Conference |
|
|
| |
Notes |
|
Approved |
yes |
|
| |
Call Number |
IPEV @ Thierry.Lemaire @ |
Serial |
5633 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Reijmer, C.H.; Oerlemans, J. |
|
| |
Title |
Temporal and spatial variability of the surface energy balance in Dronning Maud Land, East Antarctica |
Type |
Journal Article |
| |
Year |
2002 |
Publication |
Journal of geophysical research-atmospheres |
Abbreviated Journal |
J. Geophys. Res. |
|
| |
Volume |
107 |
Issue |
|
Pages |
|
|
| |
Keywords |
1827 Hydrology: Glaciology; 1863 Hydrology: Snow and ice; 3307 Meteorology and Atmospheric Dynamics: Boundary layer processes; 3349 Meteorology and Atmospheric Dynamics: Polar meteorology; 9310 Information Related to Geographic Region: Antarctica |
|
| |
Abstract |
We present data of nine Automatic Weather Stations (AWS), which are located in Dronning Maud Land (DML), East Antarctica, since the austral summer of 1997. Potential temperature and wind speed are maximum at the sites with the steepest surface slope, i.e., at the edge of the Antarctic plateau. Specific humidity and accumulation decrease with elevation and distance from the coast. The annual average energy gain at the surface from the downward sensible heat flux varies between ?3 W m?2 and ?25 W m?2, with the highest values at the sites with the largest surface inclination and wind speeds. The net radiative flux is negative and largely balances this sensible heat flux and ranges from ??2 W m?2 to ??28 W m?2; maximum values can be linked to maxima in surface slope and wind speed, and suggest a strong connection between the heat budget and the katabatic flow in DML. The average latent heat flux is generally small and negative (??1 W m?2) indicating a slight net mass loss through sublimation. |
|
| |
Programme |
960 |
|
| |
Campaign |
|
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
American Geophysical Union |
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Summary Language |
|
Original Title |
|
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0148-0227 |
ISBN |
|
Medium |
|
|
| |
Area |
|
Expedition |
|
Conference |
|
|
| |
Notes |
|
Approved |
yes |
|
| |
Call Number |
IPEV @ Thierry.Lemaire @ |
Serial |
5638 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Priestley, K.; Debayle, E. |
|
| |
Title |
Seismic evidence for a moderately thick lithosphere beneath the Siberian Platform |
Type |
Journal Article |
| |
Year |
2003 |
Publication |
Geophysical research letters |
Abbreviated Journal |
|
|
| |
Volume |
30 |
Issue |
|
Pages |
|
|
| |
Keywords |
7207 Seismology: Core and mantle; 7218 Seismology: Lithosphere and upper mantle; 7255 Seismology: Surface waves and free oscillations |
|
| |
Abstract |
We have built a Sv-wavespeed tomographic model for the upper mantle beneath the Siberian platform and surrounding region derived from the analysis of more than 13,000 fundamental and higher mode regional waveforms. The dense path coverage and rich higher mode content of the data allow building an upper mantle image with an horizontal resolution of a few hundred kilometers extending to ?400 km depth. The high velocity, upper mantle lid or seismic lithosphere is ?200 km thick beneath most of the Siberian platform but may extend to ?250 km depth beneath small areas. A high velocity seismic lid also underlies a large region west of the Siberian platform. Our observation of a ?200 thick seismic lithosphere beneath the Siberian platform on the slow-moving Eurasian plate, similar to the thickness of the seismic lithosphere beneath Precambrian terrains on the fast-moving Australian plate, suggests that a moderately thick seismic lithosphere beneath Precambrian terrains may be more common than previously supposed. |
|
| |
Programme |
133;906 |
|
| |
Campaign |
|
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
American Geophysical Union |
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Summary Language |
|
Original Title |
|
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0094-8276 |
ISBN |
|
Medium |
|
|
| |
Area |
|
Expedition |
|
Conference |
|
|
| |
Notes |
|
Approved |
yes |
|
| |
Call Number |
IPEV @ Thierry.Lemaire @ |
Serial |
5630 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Legrand, M.; Preunkert, S.; Galy-Lacaux, C.; Liousse, C.; Wagenbach, D. |
|
| |
Title |
Atmospheric year-round records of dicarboxylic acids and sulfate at three French sites located between 630 and 4360 m elevation |
Type |
Journal Article |
| |
Year |
2005 |
Publication |
Journal of geophysical research-atmospheres |
Abbreviated Journal |
J. Geophys. Res. |
|
| |
Volume |
110 |
Issue |
|
Pages |
|
|
| |
Keywords |
dicarboxylates; secondary production; high-elevated sites; 0365 Atmospheric Composition and Structure: Troposphere: composition and chemistry; 0368 Atmospheric Composition and Structure: Troposphere: constituent transport and chemistry; 0322 Atmospheric Composition and Structure: Constituent sources and sinks |
|
| |
Abstract |
An atmospheric year-round study of C2–C5 dicarboxylic acids (oxalic, malonic, succinic, malic, and glutaric) and sulfate was conducted in 2002 and 2003 at three remote western Europe continental sites located at different elevations (from 630 to 4360 m asl). Whatever the site and the season, oxalic acid is always the dominant diacid (average 64% of total dicarboxylic acids) followed by malonic acid (15% of total dicarboxylic acids). High correlation coefficients are observed between C3 (malonic), C4 (malic and succinic), and C5 (glutaric) acids and oxalic acid. These strong relationships between C2–C5 diacids support the hypothesis of a common production of these diacids through the aqueous phase chemistry of glutaric acid. Data gained at different elevations are here useful to compare the mass formation rates of sulfate and dicarboxylic acids. It is shown that in summer the decrease of the sum of dicarboxylic acids with height is far less pronounced than the decrease of sulfate (a factor of 2 instead of 6.8 from 630 to 4360 m asl). That demonstrates that the production of dicarboxylic acids occurs at up to 4300 m elevation while the production of sulfate from SO2 mainly takes place between the boundary layer and 3000 m elevation. With respect to summer 2002 the sum of dicarboxylic acids was enhanced in summer 2003 (from 136 to 331 ng m?3 STP at 2870 m asl, for instance) whereas a weaker increase is observed for sulfate (from 1700 to 2500 ng m?3 STP at 2870 m asl). These changes are attributed to the particular summer 2003 conditions which led to enhanced level of oxidants (strengthened secondary productions) and warmer temperatures (enhanced emissions of biogenic precursors of diacids). |
|
| |
Programme |
414 |
|
| |
Campaign |
|
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
American Geophysical Union |
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Summary Language |
|
Original Title |
|
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0148-0227 |
ISBN |
|
Medium |
|
|
| |
Area |
|
Expedition |
|
Conference |
|
|
| |
Notes |
|
Approved |
yes |
|
| |
Call Number |
IPEV @ Thierry.Lemaire @ |
Serial |
5575 |
|
| Permanent link to this record |
