Neon and argon optical emission lines in ionized gaseous nebulae: implications and applications     

Enrique Pérez-Montero †  Guillermo F. Hägele ‡  Thierry Contini  Ángeles I. Díaz § 《Monthly notices of the Royal Astronomical Society》2007,381(1):125-135

In this work, we present a study of the strong optical collisional emission lines of Ne and Ar in an heterogeneous sample of ionized gaseous nebulae for which it is possible to derive directly the electron temperature and hence the chemical abundances of Ne and Ar. We calculate using a grid of photoionization models new ionization correction factors for these two elements and we study the behaviour of Ne/O and Ar/O abundance ratios with metallicity. We find a constant value for Ne/O, while there seems to be some evidence for the existence of negative radial gradients of Ar/O over the discs of some nearby spirals. We study the relation between the intensities of the emission lines of [Ne  iii ] at 3869 Å and [O  iii ] at 4959 and 5007 Å. This relation can be used in empirical calibrations and diagnostic ratios extending their applicability to bluer wavelengths and therefore to samples of objects at higher redshifts. Finally, we propose a new diagnostic using [O  ii ], [Ne  iii ] and Hδ emission lines to derive metallicities for galaxies at high z .  相似文献   

Upper limits on hydrogen halides in Jupiter from Cassini/CIRS observations     

Thierry Fouchet  Glenn Orton  Simon B. Calcutt 《Icarus》2004,170(1):237-241

We have determined the following upper limits for the mole fraction of hydrogen halides in Jupiter's atmosphere from Cassini/CIRS observations: [HF]<2.7×10−11, [HCl]<2.3×10−9, [HBr]<1.0×10−9, [HI]<7.6×10−9. These limits are smaller than solar composition for HF and HCl, and support the halogens' condensation in ammonium salts predicted by thermochemical models for the upper jovian troposphere.  相似文献   

Tectonique superposée de la zone de faille d’Arakapas (Massif de Troodos,Chypre)     

Lapierre Henriette  Angelier Jacques  Cogné Xavier  Grand Thierry  Mascle Georges 《Geodinamica Acta》2013,26(4):197-206

Résumén

Une analyse tectonique du couloir faillé d’Arakapas est menée à partir de la mesure de plus de 3 000 plans striés relevés dans les formations ophiolitiques du Troodos et du Kellaki. Des mesures ont également été effectuées dans les formations du Crétacé terminal — Paléogène et du Néogène, afin de préciser l’âge des différents stades de la déformation. Elles ont été traitées par les méthodes des dièdres droits et du calcul du tenseur des contraintes. Il est montré que le couloir d’Arakapas a été le siège de plusieurs déformations successives. Au Néogène règne un régime en extension qui succède à un jeu décrochant dextre contemporain des compressions d’âge Crétacé terminal à Miocène. Un jeu décrochant antérieur peut-être mis en évidence. Il serait compatible avec le fonctionnement en faille transformante océanique proposé par divers auteurs.  相似文献   

极地区域气溶胶地基遥感观测及分析   总被引：1，自引：0，他引：1  

李东辉  李正强  卞良  李凯涛  李保生  顾行发  PODVIN Thierry 《遥感学报》2013,17(3):553-565

依据全球气溶胶自动观测网在极地区域的观测,对以下问题进行了讨论:(1)温度订正在极地气溶胶光学厚度观测中的重要性及订正方法;(2)在极地进行仪器常数标定的可行性分析及温度效应的影响;(3)利用天空散射光观测反演气溶胶微物理和光学特性参数(粒子谱分布、散射相函数、复折射指数、单次散射反照率等)时,关于观测几何选择的问题,以及针对极地区域气溶胶特性的初步反演结果。这些研究可以为中国未来在两极地区开展基于自动太阳-天空辐射计的气溶胶地基遥感观测提供参考,为极地区域气溶胶卫星遥感及气候效应评估等研究提供重要支撑。  相似文献   

Bedrock versus superficial deposits in the Swiss Jura Mountains: what is the legitimate soil parent material?     

Loraine Martignier  Thierry Adatte  Eric P. Verrecchia 《地球表面变化过程与地形》2013,38(4):331-345

Soils are generally considered to be the result of in situ weathered products of geological substrata. Nevertheless, the Earth's surface is mainly composed of superficial deposits made of sediments reworked during periods of climate instability (glaciation, aridification, flooding, etc.). But to what extent do these deposits influence present‐day soil development and/or lessen the contribution of the geological substratum? In the Swiss Jura Mountains, characterization and distribution of superficial deposits along a toposequence are used in order to decipher the polygenic sources of soil parent materials and question the importance of lithodependence in soil development. The in situ weathering material and the allochtonous deposits are discriminated through analysis of mineralogical composition, grain size distribution of the soil mineral fraction, and multivariate statistical treatment. As expected, calcite is dominant in the autochonous mineral phase, leading to high pH values in deep soil layers. However, the mineralogical composition of the surficial deposits is made of local mineral components mixed with allochtonous aeolian deposits. This exogenous material is dominated by quartz and phyllosilicates, and is reflected by low pH values in soil surficial horizons. The grain size distribution curves of the insoluble residue from bedrocks are unimodal and dominated by fine loam and clays. In contrast, surficial deposits display polymodal curves, demonstrating the contribution of various aeolian episodes and/or sources. Analysis of the surface texture of quartz sand grains shows glacial marks intersected by aeolian shock marks, indicating the posteriority of wind transportation. Loess material originates from Alpine moraines of the Swiss Plateau and is mixed with deposits originating from more proximal Jura moraines, diluting the Alpine signature. Consequently, the soil development does not follow the expected and conventional decalcification process, but is directly influenced by the origin of the primary sediments (even when present only in small amounts) and their evolution. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

An assessment of the mixed layer salinity budget in the tropical Pacific Ocean. Observations and modelling (1990–2009)     

Audrey E. A. Hasson  Thierry Delcroix  Raphaël Dussin 《Ocean Dynamics》2013,63(2-3):179-194

This paper investigates mechanisms controlling the mixed-layer salinity (MLS) in the tropical Pacific during 1990–2009. We use monthly 1°?×?1° gridded observations of salinity, horizontal current and fresh water flux, and a validated ocean general circulation model with no direct MLS relaxation in both its full resolution (0.25° and 5 days) and re-sampled as the observation time/space grid resolution. The present study shows that the mean spatial distribution of MLS results from a subtle balance between surface forcing (E???P, evaporation minus precipitation), horizontal advection (at low and high frequencies) and subsurface forcing (entrainment and mixing), all terms being of analogous importance. Large-scale seasonal MLS variability is found mainly in the Intertropical and South Pacific Convergence Zones due to changes in their meridional location (and related heavy P), in the North Equatorial Counter Currents, and partly in the subsurface forcing. Maximum interannual variability is found in the western Pacific warm pool and in both convergence zones, in relation to El Niño Southern Oscillation (ENSO) events. In the equatorial band, this later variability is due chiefly to the horizontal advection of low salinity waters from the western to the central-eastern basin during El Niño (and vice versa during La Niña), with contrasted evolution for the Eastern and Central Pacific ENSO types. Our findings reveal that all terms of the MLS equation, including high-frequency (<1 month) salinity advection, have to be considered to close the salinity budget, ruling out the use of MLS (or sea surface salinity) only to directly infer the mean, seasonal and/or interannual fresh water fluxes.  相似文献   

Diagnostic description and geographic distribution of four new cryptic species of the blue-spotted maskray species complex(Myliobatoidei: Dasyatidae; Neotrygon spp.) based on DNA sequences     

Philippe BORSA  Irma S.ARLYZA  Thierry B.HOAREAU  Kang-Ning SHEN 《中国海洋湖沼学报》2018,(3)

  相似文献   

Partitioning evapotranspiration fluxes into soil evaporation and plant transpiration using water stable isotopes under controlled conditions   总被引：1，自引：0，他引：1  

Youri Rothfuss  Philippe Biron  Isabelle Braud  Laurent Canale  Jean‐Louis Durand  Jean‐Paul Gaudet  Patricia Richard  Michel Vauclin  Thierry Bariac 《水文研究》2010,24(22):3177-3194

  相似文献   

Sampling strategies based on sets of behavioural parameters. Application to a simple pesticide fate model     

Thierry Leviandier  Stéphanie Madier  Sylvain Payraudeau 《Stochastic Environmental Research and Risk Assessment (SERRA)》2012,26(4):557-568

Sampling strategies are necessary to minimise the cost of data acquisition. We consider the case when several samples must be analysed at the same time, knowing rainfall data, optionally discharge data. We assume also that a rainfall-runoff and pesticide transfer model is available. Three methods are presented based on behavioural sets calculated on prior events, which provide optimal sampling times with respect to different statistical criteria, for a fixed number of samples. A methodology to compare these strategies, adapted to a context of data scarcity is proposed for proper validation. We consider that the combination of a model and a strategy is efficient if it does better than a strategy without a model based on equal volumes. Even with a simple and relatively poor model, it can be concluded that the different strategies are efficient and show similar efficiency in spite of their different levels of conceptual and algorithmic complexity.  相似文献   

Astrodynamical Space Test of Relativity Using Optical Devices I (ASTROD I)—A class-M fundamental physics mission proposal for Cosmic Vision 2015–2025     

Thierry Appourchaux  Raymond Burston  Yanbei Chen  Michael Cruise  Hansjörg Dittus  Bernard Foulon  Patrick Gill  Laurent Gizon  Hugh Klein  Sergei Klioner  Sergei Kopeikin  Hans Krüger  Claus Lämmerzahl  Alberto Lobo  Xinlian Luo  Helen Margolis  Wei-Tou Ni  Antonio Pulido Patón  Qiuhe Peng  Achim Peters  Ernst Rasel  Albrecht Rüdiger  Étienne Samain  Hanns Selig  Diana Shaul  Timothy Sumner  Stephan Theil  Pierre Touboul  Slava Turyshev  Haitao Wang  Li Wang  Linqing Wen  Andreas Wicht  Ji Wu  Xiaomin Zhang  Cheng Zhao 《Experimental Astronomy》2009,23(2):491-527

ASTROD I is a planned interplanetary space mission with multiple goals. The primary aims are: to test general relativity with an improvement in sensitivity of over three orders of magnitude, improving our understanding of gravity and aiding the development of a new quantum gravity theory; to measure key solar system parameters with increased accuracy, advancing solar physics and our knowledge of the solar system; and to measure the time rate of change of the gravitational constant with an order of magnitude improvement and the anomalous Pioneer acceleration, thereby probing dark matter and dark energy gravitationally. It is an international project, with major contributions from Europe and China and is envisaged as the first in a series of ASTROD missions. ASTROD I will consist of one spacecraft carrying a telescope, four lasers, two event timers and a clock. Two-way, two-wavelength laser pulse ranging will be used between the spacecraft in a solar orbit and deep space laser stations on Earth, to achieve the ASTROD I goals. A second mission, ASTROD (ASTROD II) is envisaged as a three-spacecraft mission which would test General Relativity to 1 ppb, enable detection of solar g-modes, measure the solar Lense–Thirring effect to 10 ppm, and probe gravitational waves at frequencies below the LISA bandwidth. In the third phase (ASTROD III or Super-ASTROD), larger orbits could be implemented to map the outer solar system and to probe primordial gravitational-waves at frequencies below the ASTROD II bandwidth.

Wei-Tou NiEmail:

  相似文献