Multivariate density model comparison for multi-site flood-risk rainfall in the French Mediterranean area     

Julie Carreau  Christophe Bouvier 《Stochastic Environmental Research and Risk Assessment (SERRA)》2016,30(6):1591-1612

The French Mediterranean area is subject to intense rainfall events which might cause flash floods, the main natural hazard in the area. Flood-risk rainfall is defined as rainfall with a high spatial average and encompasses rainfall which might lead to flash floods. We aim to compare eight multivariate density models for multi-site flood-risk rainfall. In particular, an accurate characterization of the spatial variability of flood-risk rainfall is crucial to help understand flash flood processes. Daily data from eight rain gauge stations at the Gardon at Anduze, a small Mediterranean catchment, are used in this work. Each multivariate density model is made of a combination of a marginal model and a dependence structure. Two marginal models are considered: the Gamma distribution (parametric) and the Log-Normal mixture (non-parametric). Four dependence structures are included in the comparison: Gaussian, Student t, Skew Normal and Skew t in increasing order of complexity. They possess a representative set of theoretical properties (symmetry/asymmetry and asymptotic dependence/independence). The multivariate models are compared in terms of three types of criteria: (1) separate evaluation of the goodness-of-fit of the margins and of the dependence structures, (2) model selection with a leave-one-out evaluation of the Anderson-Darling and Cramer-Von Mises statistics and (3) comparison in terms of two hydrologically interpretable quantities (return periods of the spatial average and conditional probabilities of exceedances). The key outcome of the comparison is that the Skew Normal with the Log-Normal mixture margins outperform significantly the other models. The asymmetry introduced by the Skew Normal is an added-value with respect to the Gaussian. Therefore, the Gaussian dependence structure, although widely used in the literature, is not recommended for the data in this study. In contrast, the asymptotically dependent models did not provide a significant improvement over the asymptotically independent ones.  相似文献   

Quartz Reference Materials for Oxygen Isotope Analysis by SIMS          下载免费PDF全文

Susanne Seitz  Lukas P. Baumgartner  Anne‐Sophie Bouvier  Benita Putlitz  Torsten Vennemann 《Geostandards and Geoanalytical Research》2017,41(1):69-75

Two quartz samples of igneous origin, UNIL‐Q1 (Torres del Paine Intrusion, Chile) and BGI‐Q1 (Shandong province, China), were calibrated for their oxygen isotope composition for SIMS measurements. UNIL‐Q1 and BGI‐Q1 were evaluated for homogeneity using SIMS. Their reference δ¹⁸O values were determined by CO₂ laser fluorination. The average δ¹⁸O value found for UNIL‐Q1 is 9.8 ± 0.06‰ and that for BGI‐Q1 is 7.7 ± 0.11‰ (1s). The intermediate measurement precision of SIMS oxygen isotope measurements was 0.32–0.41‰ (2s; UNIL‐Q1) and 0.40–0.48‰ (2s; BGI‐Q1), respectively. While less homogeneous in its oxygen isotope composition, BGI‐Q1 is also suitable for SIMS trace element measurements.  相似文献   

Formal aspects of possible hierarchies within a stellar system     

J. B. Nugeyre  P. Bouvier 《Celestial Mechanics and Dynamical Astronomy》1981,25(1):51-64

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Post-Newtonian approximations in scale covariant gravitation     

P. Bouvier 《Astrophysics and Space Science》1982,87(1-2):105-116

The scale covariant theory of gravitation, outlined by Dirac (1973), later developed by Canutoet al. (1977), revisited by Maeder and Bouvier (1978, 1979), takes into account the possible relative changes in the system of units associated with different physical interactions; in this respect, it represents a generalization of the General Relativity Theory. In the line of the latter aforementioned papers, we study here the case of a weak gravitational field, well suited to the inner motions of a star or galaxy cluster, in order to see whether the post-Newtonian approximation scheme can consistently fit into the scale covariant formalism. Such a task turns out to be feasible when the gauge terms met in the field equations are handled in an appropriate way, but only if the gauge or metrical connection vector is inversely proportional to cosmic time, as it should be in consequence of the outer boundary condition imposed on the solution of the field equations describing the Newtonian and the first post-Newtonian approximation.  相似文献   

The age of SNC meteorites and the antiquity of the Martian surface     

Audrey Bouvier  Janne Blichert-Toft  Francis Albarède 《Earth and Planetary Science Letters》2005,240(2):221-233

We report new Sm-Nd, Lu-Hf, and Pb-Pb mineral and whole-rock isotope data for the basaltic shergottite Zagami, as well as Pb-Pb whole-rock isotope data for the basaltic shergottite Los Angeles, the lherzolitic shergottite Dar-al-Gani 476 (DaG 476), and the clinopyroxenite Nakhla. In agreement with previous findings, our new Sm-Nd and Lu-Hf mineral ages on the Martian meteorite Zagami are young (155 and 185 Ma, respectively). The ²⁰⁷Pb/²⁰⁶Pb-²⁰⁴Pb/²⁰⁶Pb compositions of the insoluble fractions of shergottites (Zagami, Los Angeles, and literature data for Shergotty and EETA79001) form an excellent alignment indicative of a 4.0 Ga crystallization age. The range of Pb isotope compositions observed in the leachates of these samples attests to negligible contamination of the shergottites by terrestrial Pb and argues against mixing relationships. The age of 4.048 ± 0.017 Ga (MSWD = 1.5) provided by the Pb isotope compositions of the Zagami whole-rock and residues is therefore taken to date the crystallization of this rock, which, so far, was believed to be only ∼ 180 Ma old. Based on this result, we argue that the lithosphere of Mars is extremely old and that most mineral ages were reset recently by acidic aqueous solutions percolating through the Martian surface. This interpretation is consistent with photographic interpretations of erosional features on Mars. It also relieves the constraint imposed by the presence of anomalies of ¹⁴²Nd and ¹⁸²W (both products of extinct radioactive nuclides) that the Martian mantle should have preserved primordial isotopic heterogeneities, thus allowing for the planet interior to be actively convecting.  相似文献   

The Meteoritical Bulletin,no. 108     

Jrme Gattacceca  Francis M. McCubbin  Audrey Bouvier  Jeffrey N. Grossman 《Meteoritics & planetary science》2020,55(5):1146-1150

Meteoritical Bulletin 108 contains 2141 meteorites including 12 falls (Aguas Zarcas, Benenitra, Jalangi, Komaki, Ksar El Goraane, Mhabes el Hamra, Natun Balijan, Oued Sfayat, Shidian, Taqtaq‐e Rasoul, Tocache, Viñales), with 1640 ordinary chondrites, 149 carbonaceous chondrites, 134 HED achondrites, 45 lunar meteorites, 38 ureilites, 27 iron meteorites, 23 Martian meteorites, 22 primitive achondrites, 19 Rumuruti chondrites, 15 mesosiderites, 10 enstatite chondrites, 7 ungrouped achondrites, 4 pallasites, 4 ungrouped chondrites, and 4 angrites. Nine hundred and nine meteorites are from Africa, 747 from Antarctica, 279 from South America, 148 from Asia, 29 from North America, 18 from Oceania, 6 from Europe (including 2 from Russia), and 5 from unknown locations.  相似文献   

Raman spectroscopy of shocked enstatite-rich meteorites     

Bidong Zhang  Sean R. Shieh  Anthony C. Withers  Audrey Bouvier 《Meteoritics & planetary science》2018,53(10):2067-2077

We present Raman patterns of enstatite in different classes of enstatite-rich chondrites and achondrites of various shock levels as previously reported from petrographic observations and X-ray diffraction analyses. Thin sections or mineral separates of four enstatite chondrites (LaPaz Icefield [LAP] 02225, MacAlpine Hills [MAC] 02837, Pecora Escarpment [PCA] 91020, and Itqiy), three aubrites (Larkman Nunatak [LAR] 04316, Khor Temiki, and Allan Hills [ALH] 84008), and a ureilite (Sayh al Uhaymir [SaU] 559) were examined by laser Raman spectroscopy. We find that the frequencies of fundamental Raman peaks of enstatites from the chondrites and aubrites deviate by ≤2 cm⁻¹ from the values for unshocked enstatite. This small difference implies a negligible effect of shock metamorphism on peak positions. Significant differences (<6 cm⁻¹) for peak positions are found for the pyroxenes of SaU 559 and may be attributed to minor substitution of Fe and Ca for Mg. Linear regressions of peak widths of enstatite chondrites against their established shock stages show a strong positive correlation for each mode (r² > 0.94). From this linear relationship, the 343 and 1014 cm⁻¹ peaks of the aubrites coincide with S4 determined from petrography. For Itqiy, we find S4–5, while the shock levels of SaU 559 exceed the petrologic scheme (S1–6), suggesting that the ureilite might have sustained multiple shock events or have been deformed in a high-pressure environment. Alternatively, for Itqiy (peak 343 cm⁻¹) and SaU 559 (all peaks) enstatites, minor substitutions of Fe and Ca for Mg may have further broadened their peak widths.  相似文献   

The Meteoritical Bulletin,No. 103          下载免费PDF全文

Alex Ruzicka  Jeffrey Grossman  Audrey Bouvier  Carl B. Agee 《Meteoritics & planetary science》2017,52(5):1014-1014

Meteoritical Bulletin 103 contains 2582 meteorites including 10 falls (Ardón, Demsa, Jinju, Kri?evci, Kuresoi, Novato, Tinajdad, Tirhert, Vicência, Wolcott), with 2174 ordinary chondrites, 130 HED achondrites, 113 carbonaceous chondrites, 41 ureilites, 27 lunar meteorites, 24 enstatite chondrites, 21 iron meteorites, 15 primitive achondrites, 11 mesosiderites, 10 Martian meteorites, 6 Rumuruti chondrites, 5 ungrouped achondrites, 2 enstatite achondrites, 1 relict meteorite, 1 pallasite, and 1 angrite, and with 1511 from Antarctica, 588 from Africa, 361 from Asia, 86 from South America, 28 from North America, and 6 from Europe. Note: 1 meteorite from Russia was counted as European. The complete contents of this bulletin (244 pages) are available on line. Information about approved meteorites can be obtained from the Meteoritical Bulletin Database (MBD) available on line at http://www.lpi.usra.edu/meteor/ .  相似文献   

The Meteoritical Bulletin,No. 105          下载免费PDF全文

Audrey Bouvier  Jérôme Gattacceca  Jeffrey Grossman  Knut Metzler 《Meteoritics & planetary science》2017,52(11):2411-2411

Meteoritical Bulletin 105 contains 2666 meteorites including 12 falls (Aouinet Legraa, Banma, Buritizal, Ejby, Kamargaon, Moshampa, Mount Blanco, Murrili, Osceola, Sariçiçek, Sidi Ali Ou Azza, Stubenberg), with 2244 ordinary chondrites, 142 HED achondrites, 116 carbonaceous chondrites, 37 Lunar meteorites, 20 enstatite chondrites, 20 iron meteorites, 20 ureilites, 19 Martian meteorites, 12 Rumuruti chondrites, 10 primitive achondrites, 9 mesosiderites, 5 angrites, 4 pallasites, 4 ungrouped achondrites, 2 ungrouped chondrites, 1 enstatite achondrite, and 1 relict meteorite, and with 1545 from Antarctica, 686 from Africa, 245 from Asia, 147 from South America, 22 from North America, 14 from Europe, 5 from Oceania, 1 from unknown origin. Note: 5 meteorites from Russia were counted as European. It also includes a list of approved new Dense Collection Areas and a nomenclature of the Aletai (IIIE‐an) iron meteorites from Xinjiang, China.  相似文献   

The Monitor project: rotation periods of low-mass stars in M50     

Jonathan Irwin  Suzanne Aigrain  Jerome Bouvier  Leslie Hebb  Simon Hodgkin  Mike Irwin  Estelle Moraux 《Monthly notices of the Royal Astronomical Society》2009,392(4):1456-1466

We report on the results of a time-series photometric survey of M50 (NGC 2323), a  ∼130 Myr  open cluster, carried out using the Cerro Tololo Inter-American Observatory (CTIO) 4-m Blanco telescope and Mosaic-II detector as part of the Monitor project. Rotation periods were derived for 812 candidate cluster members over the mass range  0.2 ≲ M /M_⊙≲ 1.1  . The rotation period distributions show a clear mass-dependent morphology, statistically indistinguishable from those in NGC 2516 and M35 taken from the literature. Due to the availability of data from three observing runs separated by ∼10 and 1 month time-scales, we are able to demonstrate clear evidence for evolution of the photometric amplitudes, and hence spot patterns, over the 10 month gap. We are not able to constrain the time-scales for these effects in detail due to limitations imposed by the large gaps in our sampling, which also prevent the use of the phase information.  相似文献