A recent build-up of atmospheric CO₂ over Europe. Part 1: observed signals and possible explanations     

By MICHEL RAMONET  PHILIPPE CIAIS  TUULA AALTO  CÉLINE AULAGNIER  FRÉDÉRIC CHEVALLIER  DOMENICO CIPRIANO  THOMAS J. CONWAY  LASZLO HASZPRA  VICTOR KAZAN  FRANK MEINHARDT  JEAN-DANIEL PARIS  MARTINA SCHMIDT  PETER SIMMONDS  IRÈNE XUEREF-RÉMY  JAROSLAW N. NECKI 《Tellus. Series B, Chemical and physical meteorology》2010,62(1):1-13

We analysed interannual and decadal changes in the atmospheric CO₂ concentration gradient (ΔCO₂) between Europe and the Atlantic Ocean over the period 1995–2007. Fourteen measurement stations are used, with Mace-Head being used to define background conditions. The variability of ΔCO₂ reflects fossil fuel emissions and natural sinks activity over Europe, as well as atmospheric transport variability. The mean ΔCO₂ increased by 1–2 ppm at Eastern European stations (∼30% growth), between 1990–1995 and 2000–2005. This built up of CO₂ over the continent is predominantly a winter signal. If the observed increase of ΔCO₂ is explained by changes in ecosystem fluxes, a loss of about 0.46 Pg C per year would be required during 2000–2005. Even if severe droughts have impacted Western Europe in 2003 and 2005, a sustained CO₂ loss of that magnitude is unlikely to be true. We sought alternative explanations for the observed CO₂ build-up into transport changes and into regional redistribution of fossil fuel CO₂ emissions. Boundary layer heights becoming shallower can only explain 32% of the variance of the signal. Regional changes of emissions may explain up to 27% of the build-up. More insights are given in the Aulagnier et al. companion paper.  相似文献   

DECOMPOSITION OF MULTICOMPONENT SEISMIC DATA INTO PRIMARY P- AND S-WAVE RESPONSES1     

C. P. A. WAPENAAR  P. HERRMANN  D. J. VERSCHUUR  A. J. BERKHOUT 《Geophysical Prospecting》1990,38(6):633-661

Inversion of multicomponent seismic data can be subdivided in three main processes: (1) Surface-related preprocessing (decomposition of the multicomponent data into ‘primary’ P-and S-wave responses). (2) Prestack migration of the primary P- and S-wave responses, yielding the (angle-dependent) P-P, P-S, S-P and S-S reflectivity of the subsurface. (3) Target-related post-processing (transformation of the reflectivity into the rock and pore parameters in the target). This paper deals with the theoretical aspects of surface-related preprocessing. In a multicomponent seismic data set the P- and S-wave responses of the subsurface are distorted by two main causes: (1) The seismic vibrators always radiate a mixture of P- and S-waves into the subsurface. Similarly, the geophones always measure a mixture of P- and S-waves. (2) The free surface reflects any upgoing wave fully back into the subsurface. This gives rise to strong multiple reflections, including conversions. Therefore, surface-related preprocessing consists of two steps: (1)Decomposition of the multicomponent data (pseudo P- and S-wave responses) into true P- and S-wave responses. In practice this procedure involves (a) decomposition per common shot record of the particle velocity vector into scalar upgoing P- and S-waves, followed by (b) decomposition per common receiver record of the traction vector into scalar downgoing P- and S-waves. (2) Elimination of the surface-related multiple reflections and conversions. In this procedure the free surface is replaced by a reflection-free surface. The effect is that we obtain ‘primary’ P-and S-wave responses, that contain internal multiples only. An interesting aspect of the procedure is that no knowledge of the subsurface is required. In fact, the subsurface may have any degree of complexity. Both the decomposition step and the multiple elimination step are fully determined by the medium parameters at the free surface only. After surface-related preprocessing, the scalar P- and S-wave responses can be further processed independently by existing scalar algorithms.  相似文献   

Diagenesis of plattenkalk: examples from the Solnhofen area (Upper Jurassic,southern Germany)     

AXEL MUNNECKE  HILDEGARD WESTPHAL  MARTINA KÖLBL‐EBERT 《Sedimentology》2008,55(6):1931-1946

The Upper Jurassic (Tithonian) plattenkalk successions in the Solnhofen/Eichstätt area consist of alternations of thin‐bedded, laminated, fine‐grained, very pure limestones (so‐called ‘flinz beds’) and softer interlayers with slightly lower carbonate contents that are also laminated and show a foliaceous weathering appearance (‘fäule beds’). These successions are world famous for their exceptionally well‐preserved fossils. In contrast to the well‐studied wealth of fossils, little is known about the origin and diagenesis of the host rock. The reason for this discrepancy might lay in the monotonous appearance of these fine‐grained mudstones that require electron microscopical examination. Study of samples from the Solnhofen–Eichstädt area implies that flinz and fäule beds have undergone differential diagenesis. The ultrastructure of the flinz beds is characterized by interlocking microspar crystals, whereas the fäule beds show smaller and less interlocking crystals. The ratios of diagenetically inert trace elements lack clear differences between the two interlayered lithologies. While most authors agree that the flinz–fäule rhythm reflects rhythmically changing environmental conditions, primary rhythms can be taken as proven only where statistically significant differences in diagenetically resistant proxies are found. The absence of clear primary differences between flinz and fäule beds, however, leaves the question of primary differences unsolved. It is concluded that diagenesis has had a strong influence on the genesis of the lithological rhythm, and that any primary rhythm underlying the diagenetically mature rhythm is less clear than generally assumed.  相似文献   

Six-year record of atmospheric carbon dioxide and methane at a high-altitude mountain site in Poland   总被引：2，自引：0，他引：2  

JAROSLAW NECKI  MARTINA SCHMIDT  KAZIMIERZ ROZANSKI  MIROSLAW ZIMNOCH  ADAM KORUS  JAN LASA  ROLF GRAUL  INGEBORG LEVIN 《Tellus. Series B, Chemical and physical meteorology》2003,55(2):94-104

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Noble gas record and cosmic‐ray exposure history of the new CO3 chondrite Moss––Comparison with Lancé and other CO chondrite falls     

Rainer BARTOSCHEWITZ  Ulrich OTT  Luitgard FRANKE  Siegfried HERRMANN  Yukio YAMAMOTO  Keisuke NAGAO  Morten BILET  Thomas GRAU 《Meteoritics & planetary science》2010,45(8):1380-1391

Abstract– The Moss meteorite is the first CO chondrite fall after a time period of 70 yr and the least terrestrially contaminated member of its group. Its cosmic‐ray exposure (CRE) age (T₃ ～ 13.5 Ma; T₂₁ ～ 14.6 Ma) is distinct among CO chondrites and, within witnessed falls is the shortest after Lancé, which we have reanalyzed. Gas retention ages are approximately 3.95 × 10⁹ yr (U/Th‐He) and approximately 4.43 × 10⁹ yr (K/Ar), respectively. Trapped Ar, Kr, and Xe are present in Moss in abundances typical for CO chondrites, with “planetary” elemental and isotopic compositions. Presence of HL‐xenon from presolar diamonds is observed in the stepwise release analysis of Lancé. It may also be present in Moss, but it is difficult to ascertain in single‐step bulk analyses. It follows from our new data combined with a survey of the literature that the abundance of trapped gases in CO chondrites is not a good indicator of their petrological subtype.  相似文献   

Trends of pollution in rain over East Germany caused by changing emissions   总被引：2，自引：0，他引：2  

WOLFGANG MARQUARDT  ERIKA BRÜGGEMANN  RENATE AUEL  HARTMUT HERRMANN  DETLEV MÖLLER 《Tellus. Series B, Chemical and physical meteorology》2001,53(5):529-545

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Exposure of Allan Hills 84001 and other achondrites on the Antarctic ice     

U. KrHENBÜHL  K. NOLL  M. D BELI  D. GRAMBOLE  F. HERRMANN  L. TOBLER 《Meteoritics & planetary science》1998,33(4):665-670

Abstract— The enrichment of F on Antarctic meteorites is the result of their exposure to the atmosphere, and its measurement allows a subdivision of the terrestrial age into a duration of exposure on the ice and the time a meteorite was enclosed by the ice. In many cases, the periods of surface exposure are only small fractions of the terrestrial ages of meteorites collected in Antarctica. The enrichment of F on the surfaces of Antarctic achondrites was investigated by means of nuclear reaction analysis (NRA): scanning proton beams with an energy of 2.7 and 3.4 MeV were used to induce the reactions ¹⁹F(p,αγ)¹⁶O and ¹⁹F(p, p'γ)¹⁹F, respectively. Gamma signals proportional to the F content were measured. The following Antarctic achondrites were investigated: Martian meteorite ALH 84001; diogenite ALHA77256; the eucrites ALHA81011 and ALHA78132; and in addition, the H5 chondrite ALHA79025. For ALH 84001, our data indicate a period of exposure on the ice of <500 years. Thus, this specimen was enclosed in the ice >95% of its terrestrial age of 13 000 years.  相似文献   

Helium loss from Martian meteorites mainly induced by shock metamorphism: Evidence from new data and a literature compilation     

S. P. SCHWENZER  J. FRITZ  D. STÖFFLER  M. TRIELOFF  M. AMINI  A. GRESHAKE  S. HERRMANN  K. HERWIG  K. P. JOCHUM  R. K. MOHAPATRA  B. STOLL  U. OTT 《Meteoritics & planetary science》2008,43(11):1841-1859

Abstract— Noble gas data from Martian meteorites have provided key constraints about their origin and evolution, and their parent body. These meteorites have witnessed varying shock metamorphic overprinting (at least 5 to 14 GPa for the nakhlites and up to 45–55 GPa (e.g., the lherzolitic shergottite Allan Hills [ALH] A77005), solar heating, cosmic‐ray exposure, and weathering both on Mars and Earth. Influences on the helium budgets of Martian meteorites were evaluated by using a new data set and literature data. Concentrations of ³He, ⁴He, U, and Th are measured and shock pressures for same sample aliquots of 13 Martian meteorites were determined to asses a possible relationship between shock pressure and helium concentration. Partitioning of ⁴He into cosmogenic and radiogenic components was performed using the lowest ⁴He/³He ratio we measured on mineral separates (⁴He/³He = 4.1, pyroxene of ALHA77005). Our study revealed significant losses of radiogenic ⁴He. Systematics of cosmogenic ³He and neon led to the conclusion that solar radiation heating during transfer from Mars to Earth and terrestrial weathering can be ruled out as major causes of the observed losses of radiogenic helium in bulk meteorites. For bulk rock we observed a correlation of shock pressure and radiogenic ⁴He loss, ranging between ?20% for Chassigny and other moderately shocked Martian meteorites up to total loss for meteorites shocked above 40 GPa. A steep increase of loss occurs around 30 GPa, the pressure at which plagioclase transforms to maskelynite. This correlation suggests significant ⁴He loss induced by shock metamorphism. Noble gas loss in rocks is seen as diffusion due to (1) the temperature increase during shock loading (shock temperature) and (2) the remaining waste heat after adiabatic unloading (post shock temperature). Modeling of ⁴He diffusion in the main U, Th carrier phase apatite showed that post‐shock temperatures of ?300 °C are necessary to explain observed losses. This temperature corresponds to the post‐shock temperature calculated for bulk rocks shocked at about 40 GPa. From our investigation, data survey, and modeling, we conclude that the shock event during launch of the meteorites is the principal cause for ⁴He loss.  相似文献   

NEITHER BIBLICAL PLAGUE NOR PRISTINE MYTH: A LESSON FROM CENTRAL EUROPEAN SPARROWS*     

BERND HERRMANN  WILLIAM I. WOODS 《Geographical review》2010,100(2):176-186

The historical superabundance of passenger pigeons in North America and of house sparrows in Central Europe is anthropogenic; that is, the result of human actions, in these cases with unintended consequences. In this article we concentrate on the superabundance of sparrows in the eighteenth and nineteenth centuries and outline the reasons for it. Both the passenger pigeon and the sparrow examples serve as ideal types for misplaced understanding of historical numbers of individuals as indicators of assumed pristine natural situations. Both examples reflect severe human impacts on the metapopulations of the bird species. Historical data on abundance can be misleading when they are used as guides in current conservation efforts. Selections of “right” numbers are arbitrary, because no points of reference exist in natural systems.  相似文献   

ROOST SITES AND COMMUNAL BEHAVIOR OF ANDEAN CONDORS IN CHILE*     

THORA MARTINA HERRMANN  MIRCEA I. COSTINA  ALINA M. ARON COSTINA 《Geographical review》2010,100(2):246-262

The Andean condor (Vultur gryphus) is an endangered species. Even southern Patagonia, home to the most stable and abundant populations of Andean condors, is witnessing increasing pressure from development and tourism. Taking the case of Torres del Paine National Park, in the Chilean Patagonia, we examine monitoring of condor populations at roosting sites and communal bird behavior in response to humans as an effective tool for bird conservation within protected areas. Based on field data collected throughout 2007, we identify new roosting places, explore activity patterns and population characteristics of free‐ranging and roosting Andean condors, examine bird behavior in response to humans, and analyze the current and likely future ecological impacts of tourism on the condor population and its habitat. Our results reveal that the impact of tourism is still low and that the Andean condors do not seem to be declining in numbers in the park but that the importance of roosts and animal behavior in response to humans must be considered for future monitoring, bird‐conservation planning, and ecotourism management.  相似文献