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Author |
Bousquet, P.; Ciais, P.; Peylin, P.; Ramonet, M.; Monfray, P. |
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Title |
Inverse modeling of annual atmospheric CO2 sources and sinks 1. Method and control inversion |
Type |
Journal Article |
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Year |
1999 |
Publication |
Journal of geophysical research-atmospheres |
Abbreviated Journal |
J. Geophys. Res. |
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Volume |
104 |
Issue |
d21 |
Pages |
26,161–26,178 |
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Abstract |
A primary goal of developing the CO2 atmospheric measurement network is to better characterize the sources and sinks of atmospheric CO2. Atmospheric transport models can be used to interpret atmospheric measurements in terms of surface fluxes using inverse methodology. In this paper we present a three-dimensional (3-D) inversion of CO2 measurements in order to infer annual sources and sinks of CO2 at a continental scale (continents and ocean basins) for a climatological year representing the 1985–1995 period. Solving this inverse problem requires (1) a data space representing monthly CO2 measurements, here at 77 sites (surface, ships, planes), (2) a flux space describing a priori fluxes between carbon reservoirs, and (3) a 3-D transport model linking the flux space to the data space. Knowledge of these three elements, together with their associated errors, allows one to reduce the uncertainties of the CO2 sources and sinks. In the 1985–1995 period, for our control inversion, the global continental sink is found to be 2.7±1.5 Gt C yr1 for an optimized deforestation source of 1.4±0.6 Gt C yr1, yielding a net land uptake of 1.3±1.6 Gt C yr1 (fossil fuel removed). The continental partition of this budget is (in units of Gt C yr1): Arctic +0.2±0.3, North America ?0.5±0.6, Europe ?0.3±0.8, north Asia ?1.5±0.7, tropics (except Asia) +0.3±0.9, tropical Asia +0.8±0.4, and Southern Hemisphere ?0.1±0.3. The inferred partition for the controversial Northern Hemisphere CO2 sink reveals that a major sink is located over the north Asia continent. For oceans we find a net global sink of 1.5±0.5 Gt C yr1 with the following partition (in units of Gt C yr1): North Pacific ?0.3±0.2, North Atlantic ?0.8±0.3, equator +0.6±0.2, 20°S–50°S oceans ?0.9±0.3, and austral ocean ?0.1±0.1. |
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146;344 |
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American Geophysical Union |
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0148-0227 |
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yes |
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IPEV @ Thierry.Lemaire @ |
Serial |
5606 |
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Author |
Démoulin, P.; Klein, K.-L.; Goff, C.; van Driel-Gesztelyi, L.; Culhane, J.; Mandrini, C.; Matthews, S.; Harra, L. |
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Title |
Decametric N Burst: A Consequence of the Interaction of Two Coronal Mass Ejections |
Type |
Journal Article |
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Year |
2007 |
Publication |
Solar physics |
Abbreviated Journal |
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Volume |
240 |
Issue |
2 |
Pages |
301-313 |
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Abstract |
Abstract Radio emissions of electron beams in the solar corona and interplanetary space are tracers of the underlying magnetic configuration and of its evolution. We analyse radio observations from the Culgoora and WIND/WAVES spectrographs, in combination with SOHO/LASCO and SOHO/MDI data, to understand the origin of a type N burst originating from NOAA AR 10540 on January 20, 2004, and its relationship with type II and type III emissions. All bursts are related to the flares and the CME analysed in a previous paper (Goff et al., 2007). A very unusual feature of this event was a decametric type N burst, where a type III-like burst, drifting towards low frequencies (negative drift), changes drift first to positive, then again to negative. At metre wavelengths, i.e., heliocentric distances ?1.5R ?, these bursts are ascribed to electron beams bouncing in a closed loop. Neither U nor N bursts are expected at decametric wavelengths because closed quasi-static loops are not thought to extend to distances ?1.5R ?. We take the opportunity of the good multi-instrument coverage of this event to analyse the origin of type N bursts in the high corona. Reconnection of the expanding ejecta with the magnetic structure of a previous CME, launched about 8 hours earlier, injects electrons in the same manner as with type III bursts but into open field lines having a local dip and apex. The latter shape was created by magnetic reconnection between the expanding CME and neighbouring (open) streamer field lines. This particular flux tube shape in the high corona, between 5R ? and 10R ?, explains the observed type N burst. Since the required magnetic configuration is only a transient phenomenon formed by reconnection, severe timing and topological constraints are present to form the observed decametric N burst. They are therefore expected to be rare features. |
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227 |
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0038-0938 |
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yes |
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Call Number |
IPEV @ Thierry.Lemaire @ |
Serial |
5581 |
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Author |
David, C.; Keckhut, P.; Armetta, A.; Jumelet, J.; Snels, M.; Marchand, M.; Bekki, S. |
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Title |
Radiosonde stratospheric temperatures at Dumont d'Urville (Antarctica): trends and link with polar stratospheric clouds |
Type |
Journal Article |
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Year |
2010 |
Publication |
Atmos. Chem. Phys. |
Abbreviated Journal |
ACP |
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Volume |
10 |
Issue |
8 |
Pages |
3813-3825 |
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Abstract |
Temperature profiles measurements are performed daily (00:00 UT) in Dumont d'Urville (66°40' S, 140°01' E) by Météo-France, using standard radiosondes, since the International Geophysical Year in 1957. Yet, due to a 16 years data gap between 1963 and 1978, the entire dataset is only used for a qualitative overview. Only the most recent series, between 1979 and 2008, is used to investigate the inter-annual stratospheric temperatures variability. Over Dumont d'Urville, at the edge of the vortex, the annual mean temperature cooling of about 1 K/decade at 20 km is the result of the cooling trends between 0.5 and 1.4 K/decade, in summer and autumn and a warming of about 1.1 K/decade in spring. These values are consistent with values obtained using data from inner vortex stations, but with smaller amplitude. No statistically significant trend is detected in winter. We propose here the first attempt to link stratospheric temperature trends to Polar Stratospheric Cloud (PSC) trends in Antarctica based on the only continuous 20 years database of PSC lidar detection. Despite the absence of mean temperature trend during winter, the occurrence of temperatures below the NAT threshold between 1989 and 2008 reveals a significant trend of about +6%/decade. The PSCs occurrences frequency exhibits a concomitant trend of about +3%/decade, although not statistically significant. Yet, this is consistent with results obtained in the Northern Hemisphere. Such a possible positive trend in PSC occurrence has to be further explored to be confirmed or invalidated. If confirmed, this PSC trend is likely to have strong impacts, both on ozone recovery and climate evolution in Antarctica. The study also reveals the importance of trends on extreme temperatures, and not only on mean temperatures. |
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209 |
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Copernicus Publications |
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ISSN |
1680-7316 |
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yes |
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Call Number |
IPEV @ Thierry.Lemaire @ |
Serial |
6061 |
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Author |
Baker, D.F.; Law, R.M.; Gurney, K.R.; Rayner, P.; Peylin, P.; Denning, A.S.; Bousquet, P.; Bruhwiler, L.; Chen, Y.-H.; Ciais, P.; Fung, I.Y.; Heimann, M.; John, J.; Maki, T.; Maksyutov, S.; Masarie, K.; Prather, M.; Pak, B.; Taguchi, S.; Zhu, Z. |
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Title |
TransCom 3 inversion intercomparison: Impact of transport model errors on the interannual variability of regional CO2 fluxes, 1988–2003 |
Type |
Journal Article |
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Year |
2006 |
Publication |
Global biogeochemical cycles |
Abbreviated Journal |
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Volume |
20 |
Issue |
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Pages |
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Keywords |
atmospheric inversions; CO 2 fluxes; interannual variability; 0368 Atmospheric Composition and Structure: Troposphere: constituent transport and chemistry; 0322 Atmospheric Composition and Structure: Constituent sources and sinks; 0428 Biogeosciences: Carbon cycling; 0414 Biogeosciences: Biogeochemical cycles, processes, and modeling; 3260 Mathematical Geophysics: Inverse theory |
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Abstract |
Monthly CO2 fluxes are estimated across 1988–2003 for 22 emission regions using data from 78 CO2 measurement sites. The same inversion (method, priors, data) is performed with 13 different atmospheric transport models, and the spread in the results is taken as a measure of transport model error. Interannual variability (IAV) in the winds is not modeled, so any IAV in the measurements is attributed to IAV in the fluxes. When both this transport error and the random estimation errors are considered, the flux IAV obtained is statistically significant at P ? 0.05 when the fluxes are grouped into land and ocean components for three broad latitude bands, but is much less so when grouped into continents and basins. The transport errors have the largest impact in the extratropical northern latitudes. A third of the 22 emission regions have significant IAV, including the Tropical East Pacific (with physically plausible uptake/release across the 1997–2000 El Niño/La Niña) and Tropical Asia (with strong release in 1997/1998 coinciding with large-scale fires there). Most of the global IAV is attributed robustly to the tropical/southern land biosphere, including both the large release during the 1997/1998 El Niño and the post-Pinatubo uptake. |
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Programme |
439 |
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Publisher |
American Geophysical Union |
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ISSN |
0886-6236 |
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yes |
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Call Number |
IPEV @ Thierry.Lemaire @ |
Serial |
5542 |
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Author |
Cosme, E.; Genthon, C.; Martinerie, P.; Boucher, O.; Pham, M. |
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Title |
The sulfur cycle at high-southern latitudes in the LMD-ZT General Circulation Model |
Type |
Journal Article |
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Year |
2002 |
Publication |
Journal of geophysical research-atmospheres |
Abbreviated Journal |
J. Geophys. Res. |
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Volume |
107 |
Issue |
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Pages |
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Keywords |
0305 Atmospheric Composition and Structure: Aerosols and particles; 0312 Atmospheric Composition and Structure: Air/sea constituent fluxes; 0368 Atmospheric Composition and Structure: Troposphere—constituent transport and chemistry; 3319 Meteorology and Atmospheric Dynamics: General circulation; 9310 Information Related to Geographic Region: Antarctica |
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Abstract |
This modeling study was motivated by the recent publication of year-round records of dimethylsulfide (DMS) and dimethylsulfoxide (DMSO) in Antarctica, completing the available series of sulfate and methanesulfonic acid (MSA). Sulfur chemistry has been incorporated in the Laboratoire de Météorologie Dynamique-Zoom Tracers (LMD-ZT) Atmospheric General Circulation Model (AGCM), with high-resolution and improved physics at high-southern latitudes. The model predicts the concentration of six major sulfur species through emissions, transport, wet and dry deposition, and chemistry in both gas and aqueous phases. Model results are broadly realistic when compared with measurements in air and snow or ice, as well as to results of other modeling studies, at high- and middle-southern latitudes. Atmospheric MSA concentrations are underestimated and DMSO concentrations are overestimated in summer, reflecting the lack of a DMSO heterogeneous sink leading to MSA. Experiments with various recently published estimates of the rate of this sink are reported. Although not corrected in this work, other defects are identified and discussed: DMS concentrations are underestimated in winter, MSA and non-sea-salt (nss) sulfate concentrations may be underestimated at the South Pole, the deposition scheme used in the model may not be adapted to polar regions, and the model does not adequately reproduces interannual variability. Oceanic DMS sources have a major contribution to the variability of sulfur in these regions. The model results suggest that in a large part of central Antarctica ground-level atmospheric DMS concentrations are larger in winter than in summer. At high-southern latitudes, high loads of DMS and DMSO are found and the main chemical sink of sulfur dioxide (SO2) is aqueous oxidation by ozone (O3), whereas oxidation by hydrogen peroxide (H2O2) dominates at the global scale. A comprehensive modeled sulfur budget of Antarctica is provided. |
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Programme |
414;903 |
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American Geophysical Union |
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ISSN |
0148-0227 |
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yes |
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Call Number |
IPEV @ Thierry.Lemaire @ |
Serial |
5543 |
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Author |
Talbot, D.A.; Duchamp, C.; Rey, B.; Hanuise, N.; Rouanet, J.L.; Sibille, B.; Brand, M.D. |
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Title |
Uncoupling protein and ATP/ADP carrier increase mitochondrial proton conductance after cold adaptation of king penguins |
Type |
Journal Article |
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Year |
2004 |
Publication |
Journal of physiology-london |
Abbreviated Journal |
J. Physiol. (Lond.) |
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Volume |
558 |
Issue |
1 |
Pages |
123-135 |
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Abstract |
Juvenile king penguins develop adaptive thermogenesis after repeated immersion in cold water. However, the mechanisms of such metabolic adaptation in birds are unknown, as they lack brown adipose tissue and uncoupling protein-1 (UCP1), which mediate adaptive non-shivering thermogenesis in mammals. We used three different groups of juvenile king penguins to investigate the mitochondrial basis of avian adaptive thermogenesis . Skeletal muscle mitochondria isolated from penguins that had never been immersed in cold water showed no superoxide-stimulated proton conductance, indicating no functional avian UCP. Skeletal muscle mitochondria from penguins that had been either experimentally immersed or naturally adapted to cold water did possess functional avian UCP, demonstrated by a superoxide-stimulated, GDP-inhibitable proton conductance across their inner membrane. This was associated with a markedly greater abundance of avian UCP mRNA. In the presence (but not the absence) of fatty acids, these mitochondria also showed a greater adenine nucleotide translocase-catalysed proton conductance than those from never-immersed penguins. This was due to an increase in the amount of adenine nucleotide translocase. Therefore, adaptive thermogenesis in juvenile king penguins is linked to two separate mechanisms of uncoupling of oxidative phosphorylation in skeletal muscle mitochondria: increased proton transport activity of avian UCP (dependent on superoxide and inhibited by GDP) and increased proton transport activity of the adenine nucleotide translocase (dependent on fatty acids and inhibited by carboxyatractylate). |
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Programme |
131 |
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ISSN |
0022-3751 |
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Notes |
10.1113/jphysiol.2004.063768 |
Approved |
yes |
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Call Number |
IPEV @ Thierry.Lemaire @ |
Serial |
5614 |
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Author |
Tripathi, O.P.; Godin-Beekmann, S.; Lefèvre, F.; Pazmiño, A.; Hauchecorne, A.; Chipperfield, M.; Feng, W.; Millard, G.; Rex, M.; Streibel, M.; von der Gathen, P. |
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Title |
Comparison of polar ozone loss rates simulated by one-dimensional and three-dimensional models with Match observations in recent Antarctic and Arctic winters |
Type |
Journal Article |
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Year |
2007 |
Publication |
Journal of geophysical research-atmospheres |
Abbreviated Journal |
J. Geophys. Res. |
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Volume |
112 |
Issue |
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Pages |
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Keywords |
Ozone loss rates; transport model; trajectory model; 0340 Atmospheric Composition and Structure: Middle atmosphere: composition and chemistry; 0341 Atmospheric Composition and Structure: Middle atmosphere: constituent transport and chemistry; 3334 Atmospheric Processes: Middle atmosphere dynamics; 3360 Atmospheric Processes: Remote sensing; 3319 Atmospheric Processes: General circulation |
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Abstract |
Simulations of ozone loss rates using a three-dimensional chemical transport model and a box model during recent Antarctic and Arctic winters are compared with experimental loss rates. The study focused on the Antarctic winter 2003, during which the first Antarctic Match campaign was organized, and on Arctic winters 1999/2000, 2002/2003. The maximum ozone loss rates retrieved by the Match technique for the winters and levels studied reached 6 ppbv/sunlit hour and both types of simulations could generally reproduce the observations at 2-sigma error bar level. In some cases, for example, for the Arctic winter 2002/2003 at 475 K level, an excellent agreement within 1-sigma standard deviation level was obtained. An overestimation was also found with the box model simulation at some isentropic levels for the Antarctic winter and the Arctic winter 1999/2000, indicating an overestimation of chlorine activation in the model. Loss rates in the Antarctic show signs of saturation in September, which have to be considered in the comparison. Sensitivity tests were performed with the box model in order to assess the impact of kinetic parameters of the ClO-Cl2O2 catalytic cycle and total bromine content on the ozone loss rate. These tests resulted in a maximum change in ozone loss rates of 1.2 ppbv/sunlit hour, generally in high solar zenith angle conditions. In some cases, a better agreement was achieved with fastest photolysis of Cl2O2 and additional source of total inorganic bromine but at the expense of overestimation of smaller ozone loss rates derived later in the winter. |
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209 |
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American Geophysical Union |
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ISSN |
0148-0227 |
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yes |
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Call Number |
IPEV @ Thierry.Lemaire @ |
Serial |
5648 |
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Author |
Miyashita, Y.; Ieda, A.; Kamide, Y.; Machida, S.; Mukai, T.; Saito, Y.; Liou, K.; Meng, C.-I.; Parks, G.K.; McEntire, R.W.; Nishitani, N.; Lester, M.; Sofko, G.J.; Villain, J.-P. |
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Title |
Plasmoids observed in the near-Earth magnetotail at X ? ?7 RE |
Type |
Journal Article |
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Year |
2005 |
Publication |
Journal of geophysical research-atmospheres |
Abbreviated Journal |
J. Geophys. Res. |
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Volume |
110 |
Issue |
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Pages |
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Keywords |
plasmoid; Geotail; 2723 Magnetospheric Physics: Magnetic reconnection; 2744 Magnetospheric Physics: Magnetotail; 2790 Magnetospheric Physics: Substorms; 2704 Magnetospheric Physics: Auroral phenomena; 2736 Magnetospheric Physics: Magnetosphere/ionosphere interactions |
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Abstract |
Recent studies have statistically shown that the magnetic reconnection site at substorm expansion onset is located in the magnetotail at X ? ?20 R E on average. For a substorm event that occurred at ?0153 UT on 2 July 1996, however, Geotail observed a series of tailward but slow flows with southward magnetic fields fairly close to the Earth at (X, Y) ? (?7, 9) R E
. The flows had enhancements of the total pressure and the total magnetic field as well as bidirectional field-aligned low-energy electrons in their central part. We interpret these as signatures for tailward moving small plasmoids with scales of ?0.5–3 R E
. Considering that GOES-8 observed a dipolarization at (X, Y) ? (?4, 5) R E after the expansion onset, we estimate that the magnetic reconnection occurred between the Geotail and GOES-8 positions. UVI auroral images from Polar and ground magnetic field data show that this substorm, initiated at ?20 hours MLT and ?64° magnetic latitude, was not very intense, and the period examined was not during an intense storm. The southward interplanetary magnetic field (IMF) was not very large, while the large duskward IMF persisted for more than 12 hours before the onset as well as the somewhat large solar wind dynamic pressure. It seems likely that the global ionospheric convection was not very strong. Locally enhanced convection and auroral oval expansion due to the large IMF B y and the solar wind dynamic pressure might lead to the initiation of the magnetic reconnection much closer to the Earth than usual. |
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312;911 |
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American Geophysical Union |
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ISSN |
0148-0227 |
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yes |
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Call Number |
IPEV @ Thierry.Lemaire @ |
Serial |
5619 |
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Author |
Schwander, J.; Jouzel, J.; Hammer, C.U.; Petit, J.-R.; Udisti, R.; Wolff, E. |
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Title |
A Tentative Chronology for the EPICA Dome Concordia Ice Core |
Type |
Journal Article |
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Year |
2001 |
Publication |
Geophysical research letters |
Abbreviated Journal |
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Volume |
28 |
Issue |
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Abstract |
A tentative age scale (EDC1) for the last 45 kyr is established for the new 788-m EPICA Dome C ice core using a simple ice flow model. The age of volcanic eruptions, the end of the Younger Dryas event, and the estimated depth and age of elevated 10Be, about 41 kyr ago were used to calibrate the model parameters. The uncertainty of EDC1 is estimated to ± 10 yr for 0 to 700 yr BP, up to ± 200 yr back to 10 kyr BP, and up to ± 2 kyr back to 41 kyr BP. The age of the air in the bubbles is calculated with a firn densification model. In the Holocene the air is about 2000 yr younger than the ice and about 5500 yr during the last glacial maximum. |
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960 |
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American Geophysical Union |
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0094-8276 |
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yes |
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IPEV @ Thierry.Lemaire @ |
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5558 |
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Author |
Vimeux, F.; Masson, V.; Jouzel, J.; Stievenard, M.; Petit, J.R. |
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Glacial-interglacial changes in ocean surface conditions in the Southern Hemisphere |
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1999 |
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Nature |
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398 |
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6726 |
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410-413 |
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The stable-isotope signatures of oxygen and hydrogen in the water of preserved ice and snow are both widely used to infer local temperatures of past environments. A derived quantity based on these two signatures, the 'deuterium excess'1, provides additional palaeoclimatic information2, 3, 4, as this parameter depends on the meteorological and oceanic characteristics of the water's source-regions (in particular, their temperature2,3 and relative humidity4). Published studies mainly focus on records from the past 40,000 years. Here we present a deuterium-excess history obtained from ice cores from Vostok, East Antarctica, spanning the full glacial–interglacial cycle of the past 150,000 years. The deuterium-excess record shows a strong anticorrelation with the Earth's orbital obliquity (approx41,000-year periodicity), and values are markedly higher during the cold stage 5d (following the last interglacial) than during the other cold stages. We interpret the relationship with obliquity as resulting from changes in the latitudinal insolation gradient affecting ocean surface conditions and, thus, the delivery of moisture to the polar region. We argue that the high 5d values, relative to other cold stages, are driven by relatively less moisture delivered from high latitudes, and more from low latitudes. The deuterium-excess in Antarctic precipitation thus provides long-term, spatially integrated information on ocean surface conditions and ocean/atmosphere circulations in the Southern Hemisphere. |
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0028-0836 |
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10.1038/18860 |
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yes |
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IPEV @ Thierry.Lemaire @ |
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5595 |
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