| |
Records |
Links |
|
Author |
Steffensen, J.P.; Andersen, K.K.; Bigler, M.; Clausen, H.B.; Dahl-Jensen, D.; Fischer, H.; Goto-Azuma, K.; Hansson, M.; Johnsen, S.J.; Jouzel, J.; Masson-Delmotte, V.; Popp, T.; Rasmussen, S.O.; Rothlisberger, R.; Ruth, U.; Stauffer, B.; Siggaard-Andersen, M.-L.; Sveinbjornsdottir, A.E.; Svensson, A.; White, J.W.C. |
|
| |
Title |
High-Resolution Greenland Ice Core Data Show Abrupt Climate Change Happens in Few Years |
Type |
Journal Article |
| |
Year |
2008 |
Publication |
Science |
Abbreviated Journal |
Science |
|
| |
Volume |
321 |
Issue |
5889 |
Pages |
680-684 |
|
| |
Keywords |
|
|
| |
Abstract |
The last two abrupt warmings at the onset of our present warm interglacial period, interrupted by the Younger Dryas cooling event, were investigated at high temporal resolution from the North Greenland Ice Core Project ice core. The deuterium excess, a proxy of Greenland precipitation moisture source, switched mode within 1 to 3 years over these transitions and initiated a more gradual change (over 50 years) of the Greenland air temperature, as recorded by stable water isotopes. The onsets of both abrupt Greenland warmings were slightly preceded by decreasing Greenland dust deposition, reflecting the wetting of Asian deserts. A northern shift of the Intertropical Convergence Zone could be the trigger of these abrupt shifts of Northern Hemisphere atmospheric circulation, resulting in changes of 2 to 4 kelvin in Greenland moisture source temperature from one year to the next. |
|
| |
Programme |
458 |
|
| |
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 |
0036-8075 |
ISBN |
|
Medium |
|
|
| |
Area |
|
Expedition |
|
Conference |
|
|
| |
Notes |
10.1126/science.1157707 |
Approved |
yes |
|
| |
Call Number  |
IPEV @ Thierry.Lemaire @ |
Serial |
5524 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Xu, G.; Frey, F.A.; Weis, D.; Scoates, J.S.; Giret, A. |
|
| |
Title |
Flood basalts from Mt. Capitole in the central Kerguelen Archipelago: Insights into the growth of the archipelago and source components contributing to plume-related volcanism |
Type |
Journal Article |
| |
Year |
2007 |
Publication |
Geochem. Geophys. Geosyst. |
Abbreviated Journal |
|
|
| |
Volume |
8 |
Issue |
|
Pages |
|
|
| |
Keywords |
Kerguelen mantle plume; Kerguelen Archipelago; Mt. Capitole; lower continental crust; Sr; Nd; Hf; Pb isotopic ratios; 1037 Geochemistry: Magma genesis and partial melting; 1038 Geochemistry: Mantle processes; 1065 Geochemistry: Major and trace element geochemistry |
|
| |
Abstract |
The Kerguelen Archipelago, constructed on the submarine Northern Kerguelen Plateau, is attributed to Cenozoic volcanism arising from the Kerguelen hot spot. Geochemical studies of 325 to 1000 m thick lava sections of the ?30 to 25 Ma flood basalt forming the bulk of the archipelago show a temporal change from older tholeiitic basalt to younger slightly alkalic basalt. This compositional transition is expressed in a 630 m lava section at Mt. Capitole where the lava sequence is lowermost tholeiitic basalt overlain by slightly alkalic basalt overlain by plagioclase-rich cumulates that are mixtures of plagioclase-phyric basalt and more evolved magmas. During growth of the archipelago, magma supply from the hot spot was variable and at times sufficiently low to enable extensive crystal fractionation; e.g., at Mt. Capitole and nearby Mt. Tourmente only 10 of 120 lava flows have >6 wt% MgO. On the basis of this study and previous isotopic data for the ?34 Ma submarine lavas erupted on the Northern Kerguelen Plateau, other flood basalt sections in the Kerguelen Archipelago, and younger lavas erupted in the archipelago and at Heard Island, there is significant Sr, Nd, Hf, and Pb isotopic heterogeneity that can be explained by two stages of mixing. The first mixing event, best shown by the submarine lavas, is between components that are related to Indian Ocean mid-ocean ridge basalt (MORB) and the Kerguelen hot spot. From ?34 Ma to <1 Ma, on average the proportion of the MORB-related component decreased. Subsequently, a second mixing process involved addition of a component with relatively high 87Sr/86Sr (>0.7060) and low 143Nd/144Nd (<0.5125) and 176Hf/177Hf (<0.2827) and nonradiogenic Pb isotope ratios (<17.9 for 206Pb/204Pb). We infer that this component was lower continental crust. |
|
| |
Programme |
444 |
|
| |
Campaign |
|
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
Bachelor's 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 |
1525-2027 |
ISBN |
|
Medium |
|
|
| |
Area |
|
Expedition |
|
Conference |
|
|
| |
Notes |
|
Approved |
yes |
|
| |
Call Number |
IPEV @ Thierry.Lemaire @ |
Serial |
5532 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
BOURGEON, S.; VIERA, V.M.; RACLOT, T.; GROSCOLAS, R. |
|
| |
Title |
Hormones and immunoglobulin levels in king penguins during moulting and breeding fasts |
Type |
Journal Article |
| |
Year |
2007 |
Publication |
Ecoscience |
Abbreviated Journal |
|
|
| |
Volume |
14 |
Issue |
4 |
Pages |
519-528 |
|
| |
Keywords |
|
|
| |
Abstract |
|
|
| |
Programme |
119;137 |
|
| |
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 |
1195-6860 |
ISBN |
|
Medium |
|
|
| |
Area |
|
Expedition |
|
Conference |
|
|
| |
Notes |
doi: 10.2980/1195-6860(2007)14[519:HAILIK]2.0.CO;2 |
Approved |
yes |
|
| |
Call Number |
IPEV @ Thierry.Lemaire @ |
Serial |
5535 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Legrand, M.; Preunkert, S.; Jourdain, B.; Aumont, B. |
|
| |
Title |
Year-round records of gas and particulate formic and acetic acids in the boundary layer at Dumont d'Urville, coastal Antarctica |
Type |
Journal Article |
| |
Year |
2004 |
Publication |
Journal of geophysical research-atmospheres |
Abbreviated Journal |
J. Geophys. Res. |
|
| |
Volume |
109 |
Issue |
|
Pages |
|
|
| |
Keywords |
0315 Atmospheric Composition and Structure: Biosphere/atmosphere interactions; 0322 Atmospheric Composition and Structure: Constituent sources and sinks; 0330 Atmospheric Composition and Structure: Geochemical cycles; 0365 Atmospheric Composition and Structure: Troposphere—composition and chemistry |
|
| |
Abstract |
Multiple year-round levels of acetate and formate in gas and aerosol phases were investigated at Dumont d'Urville (DDU, a coastal Antarctic site) by using mist chamber and aerosol filter sampling. Formate and acetate aerosol levels range from <0.5 ppt in winter to 3 ppt in summer. With corresponding gas phase levels of more than a hundred of pptv, formic and acetic acids are mainly (99%) present in the gas phase, representing the 2 major acidic gases before inorganic species (HCl, HNO3 and SO2) there. Mixing ratios of formic acid are minimal from May to August (70 pptv) and increase regularly toward November–February months when levels reach ?200 pptv. Mixing ratios of acetic acid exhibit a more well-marked seasonal cycle with values remaining close to 70 pptv from April to October and strongly increase during November–February months (mean value of 400 pptv). These seasonal changes suggest that the 2 carboxylic acids mainly originate from biogenic emissions of the Antarctic ocean whose variations follow the annual cycle of sea ice extent and solar radiation via photochemical production of alkenes from dissolved organic carbon released by phytoplankton. In summer, acetic acid levels show daily variations with maxima at noon and minima at night whereas formic acid levels peaks later in the afternoon. These dial variations in summer suggest that carboxylic acids are rapidly produced during the day and lost at night due to dry deposition on wet surface. It is suggested that the reactions of peroxy acetyl radical produced from propene with HO2 and CH3O2 in these poor NOx environments represent in summer the dominant chemical mechanisms producing acetic acid whereas ozone-alkene reactions remain of minor importance at that season. Neither ozone-alkene reactions nor aqueous phase HCHO oxidation can explain the summer levels of formic acid. In winter the long range transport of alkenes emitted at more temperate oceanic regions and reactions with ozone could account for the observed level of formic acid and possibly of acetic acid. |
|
| |
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 |
5536 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Priestley, K.; Debayle, E.; McKenzie, D.; Pilidou, S. |
|
| |
Title |
Upper mantle structure of eastern Asia from multimode surface waveform tomography |
Type |
Journal Article |
| |
Year |
2006 |
Publication |
Journal of geophysical research-atmospheres |
Abbreviated Journal |
J. Geophys. Res. |
|
| |
Volume |
111 |
Issue |
|
Pages |
|
|
| |
Keywords |
Asian upper mantle; multimode surface waveform; craton; 7208 Seismology: Mantle; 7218 Seismology: Lithosphere; 7255 Seismology: Surface waves and free oscillations; 7270 Seismology: Tomography |
|
| |
Abstract |
We present a new three-dimensional Sv wave speed and azimuthal anisotropy model for the upper mantle of eastern Asia constrained by the analysis of more than 17,000 vertical component multimode Rayleigh wave seismograms. This data set allows us to build an upper mantle model for Asia with a horizontal resolution of a few hundred kilometers extending to ?400 km depth. At 75–100 km depth, there is approximately ±9% wave speed perturbation from the “smoothed PREM” reference model used in our analysis, and the pattern of azimuthal anisotropy is complex. Both the amplitude of the Sv wave speed heterogeneity and the complexity and amplitude of the azimuthal anisotropy decrease with depth. Above ?200 km depth the upper mantle structure of the model correlates with surface geology and tectonics; below ?200 km depth the structures primarily reflect the advection of material in the upper mantle. Since shear wave speed is principally controlled by temperature rather than by composition, Vs(z) can be used to calculate the temperature T(z), and hence map the lithospheric thickness. We use the relationship of Priestley and McKenzie to produce a contour map of the lithospheric thickness of eastern Asia from the surface wave tomography. This shows an extensive region of thick lithosphere beneath the Siberian Platform and the West Siberian Basin that extends to the European Platform, forming the stable Eurasian craton or core. The eastern portion of the Eurasian craton has controlled the geometry of continental deformation and the distribution of kimberlites in eastern Asia. |
|
| |
Programme |
133 |
|
| |
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 |
5538 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Pazmiño, A.F.; Godin-Beekmann, S.; Ginzburg, M.; Bekki, S.; Hauchecorne, A.; Piacentini, R.D.; Quel, E.J. |
|
| |
Title |
Impact of Antarctic polar vortex occurrences on total ozone and UVB radiation at southern Argentinean and Antarctic stations during 1997–2003 period |
Type |
Journal Article |
| |
Year |
2005 |
Publication |
Journal of geophysical research-atmospheres |
Abbreviated Journal |
J. Geophys. Res. |
|
| |
Volume |
110 |
Issue |
|
Pages |
|
|
| |
Keywords |
polar ozone loss; UV radiation; polar vortex; 1610 Global Change: Atmosphere; 0341 Atmospheric Composition and Structure: Middle atmosphere: constituent transport and chemistry; 0340 Atmospheric Composition and Structure: Middle atmosphere: composition and chemistry |
|
| |
Abstract |
The evolution of total ozone and surface UV radiation over some stations in the southern region of South America and in Antarctica in relationship with polar vortex occurrences is analyzed using Total Ozone Mapping Spectrometer total ozone measurements and local surface UV data for the 1997–2003 period. The data are classified as a function of the position of the stations with respect to the polar vortex using equivalent latitude at 550 K isentropic level. The study of vortex occurrences showed that Ushuaia station (54.9°S) was located ?40% of the cases in the edge of the vortex and 5% inside the vortex core during the winter-spring period. Concerning the Marambio (62.2°S) and Dumont d'Urville (66.4°S) stations, located on the shore of the Antarctic continent, the analysis shows a zonal asymmetry with respect to the center of the vortex. Marambio is located around 60% of the time inside the vortex, while Dumont d'Urville is predominantly at the edge of or outside the vortex. The evolution of the equivalent latitude of the stations in the anomalous 2002 winter presents a different behavior with respect to other years in the 1997–2003 period. The persistence of the vortex core above the stations is in average 1.8 days over Ushuaia and 7.1 days over Marambio in October during the 1997–2003 period with corresponding mean total ozone columns of 208.2 and 181.4 Dobson units, respectively. When the stations are inside the vortex, the total ozone columns are generally larger at Ushuaia than at Marambio in October during the 1997–2003 period. Finally, the impact of ozone-depleted air mass occurrences on ultraviolet radiation is evaluated by relating total ozone and UV erythemal dose measured at the stations. Twofold or threefold UV dose increases were reached in the 55°–65° southern latitude region during vortex overpasses, reaching maximum UV dose around 5 kJ/m2. The average increase of UV dose could be computed at the stations considered in the study when the measurement sampling and the number of vortex occurrences was sufficient. An average increase of 67.6% of the erythemal UV dose was found in October at Ushuaia over the years 1997, 1998, and 2000. This value is strongly weighted by vortex occurrences over the station in 2000. At Marambio an average UV increase of 47.4% was found over the years 1999 and 2000. Midlatitude stations like Comodoro Rivadavia (45.8°S) are generally little affected by vortex intrusions. Nevertheless, the maximum UV dose can increase by more than 50% when the vortex passes over the station. |
|
| |
Programme |
209 |
|
| |
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 |
5601 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Fahlman, A.; Handrich, Y.; Woakes, A.J.; Bost, C.-A.; Holder, R.; Duchamp, C.; Butler, P.J. |
|
| |
Title |
Effect of fasting on the VO2-fh relationship in king penguins, Aptenodytes patagonicus |
Type |
Journal Article |
| |
Year |
2004 |
Publication |
American journal of physiology-regulatory integrative and comparative physiology |
Abbreviated Journal |
Am. J. Physiol. Regul. Integr. Comp. Physiol. |
|
| |
Volume |
287 |
Issue |
4 |
Pages |
R870-877 |
|
| |
Keywords |
|
|
| |
Abstract |
King penguins (Aptenodytes patagonicus) may fast for up to 30 days during their breeding period. As such extended fasting may affect the relationship between the rate of O2 consumption (O2) and heart rate (fH), five male king penguins were exercised at various speeds on repeated occasions during a fasting period of 24-31 days. In addition, O2 and fH were measured in the same animals during rest in cold air and water (4{degrees}C). O2 and fH at rest and O2 during exercise decreased with fasting. There was a significant relation between O2 and fH (r2 = 0.56) that was improved by including speed, body mass (Mb), number of days fasting (t), and a cross term between fH and t (r2 = 0.92). It was concluded that there was a significant change in the O2-fH relationship with fasting during exercise. As t is measurable in the field and was shown to be significant and, therefore, a practical covariate, a regression equation for use when birds are ashore was obtained by removing speed and Mb. When this equation was used, predicted O2 was in good agreement with the observed data, with an overall error of 3.0%. There was no change in the O2-fH relationship in penguins at rest in water. |
|
| |
Programme |
131;137;394 |
|
| |
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 |
0363-6119 |
ISBN |
|
Medium |
|
|
| |
Area |
|
Expedition |
|
Conference |
|
|
| |
Notes |
10.1152/ajpregu.00651.2003 |
Approved |
yes |
|
| |
Call Number |
IPEV @ Thierry.Lemaire @ |
Serial |
5548 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Tocheport, A.; Rivera, L.; Chevrot, S. |
|
| |
Title |
A systematic study of source time functions and moment tensors of intermediate and deep earthquakes |
Type |
Journal Article |
| |
Year |
2007 |
Publication |
Journal of geophysical research-atmospheres |
Abbreviated Journal |
J. Geophys. Res. |
|
| |
Volume |
112 |
Issue |
|
Pages |
|
|
| |
Keywords |
Deep earthquakes; body waves inversion; source parameters; 7203 Seismology: Body waves; 7215 Seismology: Earthquake source observations; 7209 Seismology: Earthquake dynamics; 8120 Tectonophysics: Dynamics of lithosphere and mantle: general |
|
| |
Abstract |
We developed an inversion algorithm to determine the Source Time Function and Moment Tensor of intermediate and deep earthquakes from a set of teleseismic body wave records. The method proceeds in two stages. First, a nonlinear inversion by simulated annealing is performed to simultaneously (a) align the waveforms in time, (b) determine a common source time function, and (c) measure a collection of observed station amplitudes. The station amplitudes are then used, in a second stage, as secondary observables to invert for the moment tensors. We perform three different inversions to estimate the complete moment tensor solution, the pure deviatoric solution, and the double-couple solution. All the calculations are extremely simple and, in particular, it is not necessary to compute synthetic seismograms. The method requires well-isolated phases at different stations, which restricts its application to intermediate and deep events. The algorithm is applied to the FDSN broadband records corresponding to the period 1990–2005 of worldwide intermediate and deep seismicity (depth $\ges$100 km) of magnitude greater than 6.5. The source time functions are compared to those obtained from other studies of intermediate and deep events. The moment tensors are also systematically compared to the Harvard-CMT and USGS solutions. Both show a very good agreement with previous studies. |
|
| |
Programme |
133 |
|
| |
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 |
5550 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Faccenna, C.; Rossetti, F.; Becker, T.W.; Danesi, S.; Morelli, A. |
|
| |
Title |
Recent extension driven by mantle upwelling beneath the Admiralty Mountains (East Antarctica) |
Type |
Journal Article |
| |
Year |
2008 |
Publication |
Tectonics |
Abbreviated Journal |
|
|
| |
Volume |
27 |
Issue |
|
Pages |
|
|
| |
Keywords |
Antarctica; continental tectonics; faulting; mantle dynamics; seismic tomography; 7230 Seismology: Seismicity and tectonics; 8010 Structural Geology: Fractures and faults; 8107 Tectonophysics: Continental neotectonics; 7270 Seismology: Tomography; 8122 Tectonophysics: Dynamics: gravity and tectonics |
|
| |
Abstract |
Northern Victoria Land is located at the boundary between an extended, presumably hot, region (West Antarctic Rift System) and the thick, possibly cold, East Antarctic craton. The style and timing of Tertiary deformation along with relationships with the magmatic activity are still unclear, and contrasting models have been proposed. We performed structural and morphotectonic analyses at the NE termination of northern Victoria Land in the Admiralty Mountains area, where the relationship between topography, tectonics, and magmatism is expected to be well pronounced. We found evidence of two subsequent episodes of faulting, occurring concurrently with the Neogene McMurdo volcanism. The first episode is associated with dextral transtension, and it is overprinted by extensional tectonics during the emplacement of large shield alkaline volcanoes. Upper mantle seismic tomography shows that the extensional regime is limited to regions overlying a low-velocity anomaly. We interpret this anomaly to be of thermal origin, and have tested the role of large-scale upwelling on lithosphere deformation in the area. The results of this integrated analysis suggest that the morphotectonic setting of the region and the magmatism is likely the result of upwelling flow at the boundary between the cold cratonic and the hot stretched province (WARS), at work until recent time in this portion of the northern Victoria Land. |
|
| |
Programme |
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 |
0278-7407 |
ISBN |
|
Medium |
|
|
| |
Area |
|
Expedition |
|
Conference |
|
|
| |
Notes |
|
Approved |
yes |
|
| |
Call Number |
IPEV @ Thierry.Lemaire @ |
Serial |
5551 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Legagneux, L.; Cabanes, A.; Dominé, F. |
|
| |
Title |
Measurement of the specific surface area of 176 snow samples using methane adsorption at 77 K |
Type |
Journal Article |
| |
Year |
2002 |
Publication |
Journal of geophysical research-atmospheres |
Abbreviated Journal |
J. Geophys. Res. |
|
| |
Volume |
107 |
Issue |
|
Pages |
|
|
| |
Keywords |
1863 Hydrology: Snow and ice; 3947 Mineral Physics: Surfaces and interfaces; 0399 Atmospheric Composition and Structure: General or miscellaneous; 0320 Atmospheric Composition and Structure: Cloud physics and chemistry |
|
| |
Abstract |
To help quantify exchanges between the atmosphere and the snow cover, we have measured the specific surface area (SSA) of 176 snow samples taken from the seasonal snowpack in the Alps, Svalbard, and the Canadian high Arctic around Alert. A volumetric method was used, and the adsorption isotherm of CH4 on snow at 77 K was recorded. The data were analyzed by the Brunauer-Emmett-Teller method to yield SSA and ?QCH4, the mean heat of adsorption of the first CH4 monolayer. SSA values obtained were between 100 and 1580 cm2/g. The reproducibility of the method is estimated at 6%, and the accuracy is estimated at 12%. We propose that ?QCH4 = 2240 ± 200 J/mol should be used as a criterion of reliability of the measurement. The method is described in detail to promote its use. Aged snow samples have lower SSA than fresh ones. The lowest values were found for faceted crystals and depth hoar, and the highest values were found for fresh rimed dendritic snow. A method that field investigators can use to estimate SSA from a visual examination of the snow and from a density measurement is suggested. Snow samples are classified into 14 types based on snow age and crystal shapes. Within each type, a density versus SSA correlation is determined. Our data indicate that, depending on snow type, SSA can then be estimated within 25 to 40% at the 1? confidence level with the method proposed. Preliminary data suggest that SSA spatial variability of a given snow layer is low (<5%), but metamorphism can increase it. |
|
| |
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 |
0148-0227 |
ISBN |
|
Medium |
|
|
| |
Area |
|
Expedition |
|
Conference |
|
|
| |
Notes |
|
Approved |
yes |
|
| |
Call Number |
IPEV @ Thierry.Lemaire @ |
Serial |
5552 |
|
| Permanent link to this record |
