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411.
Boumédiène Derras Pierre Yves Bard Fabrice Cotton 《Bulletin of Earthquake Engineering》2014,12(1):495-516
We have used the Artificial Neural Network method (ANN) for the derivation of physically sound, easy-to-handle, predictive ground-motion models from a subset of the Reference database for Seismic ground-motion prediction in Europe (RESORCE). Only shallow earthquakes (depth smaller than 25 km) and recordings corresponding to stations with measured $V_{s30}$ properties have been selected. Five input parameters were selected: the moment magnitude $M_{W}$ , the Joyner–Boore distance $R_{JB}$ , the focal mechanism, the hypocentral depth, and the site proxy $V_{S30}$ . A feed-forward ANN type is used, with one 5-neuron hidden layer, and an output layer grouping all the considered ground motion parameters, i.e., peak ground acceleration (PGA), peak ground velocity (PGV) and 5 %-damped pseudo-spectral acceleration (PSA) at 62 periods from 0.01 to 4 s. A procedure similar to the random-effects approach was developed to provide between and within event standard deviations. The total standard deviation ( $\sigma $ ) varies between 0.298 and 0.378 (log $_{10}$ unit) depending on the period, with between-event and within-event variabilities in the range 0.149–0.190 and 0.258–0.327, respectively. Those values prove comparable to those of conventional GMPEs. Despite the absence of any a priori assumption on the functional dependence, our results exhibit a number of physically sound features: magnitude scaling of the distance dependency, near-fault saturation distance increasing with magnitude, amplification on soft soils and even indications for nonlinear effects in softer soils. 相似文献
412.
The Jason-1 Mission 总被引:1,自引:2,他引:1
Yves M nard Lee-Lueng Fu P. Escudier F. Parisot J. Perbos P. Vincent S. Desai B. Haines G. Kunstmann 《Marine Geodesy》2003,26(3):131-146
On December 7, 2001, the Jason-1 satellite was successfully launched by a Boeing Delta II rocket from the Vandenberg site in California, USA. Its main mission was to maintain the high accuracy altimeter measurements, provided since 1992 by TOPEX/Poseidon (T/P), ensuring continuity in observing and monitoring the ocean for intraseasonal to interannual changes, mean sea level, tides, and so forth. Despite four times less mass and power, the Jason-1 system has been designed to have the same performances as T/P, measuring sea surface topography at the centimeter level. This new Centre National d'Etudes Spatiales/National Aeronautics and Space Administration (CNES/NASA) mission also provides near real-time data for sea state and ocean forecast. The first 10 months of the Jason mission were dedicated to the verification of the system performance and cross-calibration with T/P measurements. A complete CALVAL plan was conducted by the Science and Project Teams of the mission based on in situ and regional experiments, global statistical approaches, and multisatellite comparisons, taking advantage of the T/P-Jason overlap during the first months of the mission. CALVAL and first science results showed that the Jason-1 performances were compliant with prelaunch specifications. This was a needed preamble before starting the routine phase of the mission in July 2003 with generation and distribution of validated geophysical data records to the whole user community. 相似文献
413.
Laurie Boithias Yves Auda Stéphane Audry Jean-Pierre Bricquet Alounsavath Chanhphengxay Vincent Chaplot Anneke de Rouw Thierry Henry des Tureaux Sylvain Huon Jean-Louis Janeau Keooudone Latsachack Yann Le Troquer Guillaume Lestrelin Jean-Luc Maeght Pierre Marchand Pierre Moreau Andrew Noble Anne Pando-Bahuon Kongkeo Phachomphon Khambai Phanthavong Alain Pierret Olivier Ribolzi Jean Riotte Henri Robain Emma Rochelle-Newall Saysongkham Sayavong Oloth Sengtaheuanghoung Norbert Silvera Nivong Sipaseuth Bounsamay Soulileuth Xaysatith Souliyavongsa Phapvilay Sounyaphong Sengkeo Tasaketh Chanthamousone Thammahacksa Jean-Pierre Thiebaux Christian Valentin Olga Vigiak Marion Viguier Khampaseuth Xayyathip 《水文研究》2021,35(5):e14126
Mountain regions of the humid tropics are characterized by steep slopes and heavy rains. These regions are thus prone to both high surface runoff and soil erosion. In Southeast Asia, uplands are also subject to rapid land-use change, predominantly as a result of increased population pressure and market forces. Since 1998, the Houay Pano site, located in northern Lao PDR (19.85°N 102.17°E) within the Mekong basin, aims at assessing the long-term impact of the conversion of traditional slash-and-burn cultivation systems to commercial perennial monocultures such as teak tree plantations, on the catchment hydrological response and sediment yield. The instrumented site monitors hydro-meteorological and soil loss parameters at both microplot (1 m2) and small catchment (0.6 km2) scales. The monitored catchment is part of the network of critical zone observatories named Multiscale TROPIcal CatchmentS (M-TROPICS). The data shared by M-TROPICS in Houay Pano are (1) rainfall, (2) air temperature, air relative humidity, wind speed, and global radiation, (3) catchment land use, (4) stream water level, suspended particulate matter, bed particulate matter and stones, (5) soil surface features, and (6) soil surface runoff and soil detachment. The dataset has already been used to interpret suspended particulate matter and bed particulate matter sources and dynamics, to assess the impact of land-use change on catchment hydrology, soil erosion, and sediment yields, to understand bacteria fate and weed seed transport across the catchment, and to build catchment-scale models focused on hydrology and water quality issues. The dataset may be further used to, for example, assess the role of headwater catchments in large tropical river basin hydrology, support the interpretation of new variables measured in the catchment (e.g., contaminants other than faecal bacteria), and assess the relative impacts of both climate and land-use change on the catchment. 相似文献
414.
Two parameters GO2– and HO2– are defined as the differences between respectively the Gibbs free energies and the enthalpies of formation of an oxide and its corresponding aqueous cation. The Gibbs free energies and enthalpies of formation of phosphates from their consituent oxides are shown to be linear functions of respectively GO2– and HO2– of their constituent cations. 相似文献
415.
Yves?CouillardEmail author Antonella?Cattaneo Céline?Gallon Michel?Courcelles 《Journal of Paleolimnology》2008,40(1):97-114
Sources and chronologies of metal contamination were studied in sediment cores of three lakes of the Rouyn-Noranda mining
area (Québec, Canada) affected by atmospheric deposition of anthropogenic contaminants. One of the three lakes also received
acid mine drainage. The sediments were dated using 210Pb and 137Cs and analysed for stable Pb isotope ratios and for total concentrations of 15 elements (Ag, Al, Au, Ca, Cu, Cd, Fe, Hg,
Mn, Ni, P, Pb, S, Ti, Zn). Stable lead isotopic signatures helped to determine the quantitative contributions of different
industrial Pb sources to our sampling sites. This source apportionment showed the dominant influence of the Rouyn-Noranda
copper smelter in airborne Pb emissions for the decades following 1926, when industrialization began in the region. The smelter
source had a low ratio of 206Pb/207Pb ranging between 0.90 and 1.05, as typical of the Abitibi Archean sulphides. The relationships between element (metal) sedimentary
fluxes and anthropogenic Pb fluxes allowed us to infer the origin of the anthropogenic source. These relationships strongly
suggest that the copper smelter was (and may still be) an atmospheric source of Cd, Cu, Pb, Zn, Ag and Hg to the surrounding
lakes. Our study indicates that the efforts made by the Rouyn-Noranda copper smelter to reduce airborne emissions of metals
have been translated in reduced atmospheric metal loadings to the surrounding lakes. 相似文献
416.
Mohamed Sharif Berguig Mohamed Hamoudi Jean Louis Lemouël Yves Cohen 《Arabian Journal of Geosciences》2013,6(4):1063-1072
In this work, we report a global mapping of vector lunar magnetic field based on new method of separation of internal and external fields. The magnetic measurements collected during the lifetime of lunar prospector (LP) extended mission during 1999 were strongly disturbed by the solar wind, a period which coincided with a maximum of the 23 cycle activity. The multiscale wavelength external fields were analyzed using spherical harmonic transform. The external field determined by inversion was then removed from each magnetic field component for each half orbit. To map the vector magnetic crustal anomalies, all LP magnetometer data collected at low altitudes in the three different lunar environments: (1) geomagnetic tail, (2) solar wind, and (3) geomagnetic sheath were processed using this new approach. The results obtained using these selection criteria allow us to get a global coverage of the lunar surface by the vector magnetic field at variable spacecraft low altitudes. To validate our mapping, we have developed and applied a method based on properties of potential fields functions. This method can be used to determine both horizontal north and east components using only vertical component. The validated lunar internal magnetic measurements obtained at variable spacecraft altitudes were then continued to a common altitude of 30 km using an inverse method. This mapping confirms firstly the nature of the crustal sources of lunar magnetic field and clearly shows that the strongest concentrations of anomalies are associated with high albedo and/or located antipodal to large young basins (Orientale, Serenitatis, Imbrium, and Crisium) of age about 3.9 Ga. 相似文献
417.
Catherine Lalande Alexandre Forest David G. Barber Yves Gratton Louis Fortier 《Continental Shelf Research》2009
The ongoing regression of sea ice cover is expected to significantly affect the fate of organic carbon over the Arctic continental shelves. Long-term moored sediment traps were deployed in 2005–2006 in the Beaufort Sea, Northern Baffin Bay and the Laptev Sea to compare the annual variability of POC fluxes and to evaluate the factors regulating the annual cycle of carbon export over these continental shelves. Annual POC fluxes at 200 m ranged from 1.6 to 5.9 g C m−2 yr−1 with the highest export in Northern Baffin Bay and the lowest export over the Mackenzie Shelf in the Beaufort Sea. Each annual cycle exhibited an increase in POC export a few weeks before, during, or immediately following sea ice melt, but showed different patterns over the remainder of the cycle. Enhanced primary production, discharge of the Lena River, and resuspension events contributed to periods of elevated POC export over the Laptev Sea slope. High POC fluxes in Northern Baffin Bay reflected periods of elevated primary production in the North Water polynya. In the Beaufort Sea sediment resuspension contributed to most of the large export events. Our results suggest that the outer shelf of the Laptev Sea will likely sustain the largest increase in POC export in the next few years due to the large reduction in ice cover and the possible increase in the Lena River discharge. The large differences in forcing among the regions investigated reinforce the importance of monitoring POC fluxes in the different oceanographic regimes that characterize the Arctic shelves to assess the response of the Arctic Ocean carbon cycle to interannual variability and climate change. 相似文献
418.
Structure,composition, and location of organic matter in the enstatite chondrite Sahara 97096 (EH3) 总被引:1,自引:0,他引:1
Laurette PIANI François ROBERT Olivier BEYSSAC Laurent BINET Michèle BOUROT‐DENISE Sylvie DERENNE Corentin LE GUILLOU Yves MARROCCHI Smail MOSTEFAOUI Jean‐Noël ROUZAUD Aurélien THOMEN 《Meteoritics & planetary science》2012,47(1):8-29
Abstract– The insoluble organic matter (IOM) of an unequilibrated enstatite chondrite Sahara (SAH) 97096 has been investigated using a battery of analytical techniques. As the enstatite chondrites are thought to have formed in a reduced environment at higher temperatures than carbonaceous chondrites, they constitute an interesting comparative material to test the heterogeneities of the IOM in the solar system and to constrain the processes that could affect IOM during solar system evolution. The SAH 97096 IOM is found in situ: as submicrometer grains in the network of fine‐grained matrix occurring mostly around chondrules and as inclusions in metallic nodules, where the carbonaceous matter appears to be more graphitized. IOM in these two settings has very similar δ15N and δ13C; this supports the idea that graphitized inclusions in metal could be formed by metal catalytic graphitization of matrix IOM. A detailed comparison between the IOM extracted from a fresh part and a terrestrially weathered part of SAH 97096 shows the similarity between both IOM samples in spite of the high degree of mineral alteration in the latter. The isolated IOM exhibits a heterogeneous polyaromatic macromolecular structure, sometimes highly graphitized, without any detectable free radicals and deuterium‐heterogeneity and having mean H‐ and N‐isotopic compositions in the range of values observed for carbonaceous chondrites. It contains some submicrometer‐sized areas highly enriched in 15N (δ15N up to 1600‰). These observations reinforce the idea that the IOM found in carbonaceous chondrites is a common component widespread in the solar system. Most of the features of SAH 97096 IOM could be explained by the thermal modification of this main component. 相似文献
419.
1IntroductionClimatic warming, flood hazards and their impacts on human society receive increasing attention from governments and public (IPCC, 2001). During recent years, agriculture, industry and even the development of the whole national economy suffered tremendous loss resulted from flood and waterlogging hazards.The Yangtze Delta is densely populated and economically developed. Monsoonal climate, geomorphologic characteristics and human activities inflict floods and water-logging hazar… 相似文献
420.