Geodynamic Evolution of East Antarctica – A Key to East–West Gondwana Connection, Satish-Kumar, M., Motoyoshi, Y., Osanai, Y., Hiroi, Y. & Shiraishi, K., (Eds.), Special Publication Geological Society of London, vol. 308, (456 pp.).     

Geodynamic Evolution of East Antarctica &#x; A Key to East&#x;West Gondwana Connection  Satish-Kumar  M.  Motoyoshi  Y.  Osanai  Y.  Hiroi  Y. &#x; Shiraishi  K.  Special Publication Geological Society of London  vol. 《Gondwana Research》2009,16(2):362

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Application of data assimilation for improving forecast of water levels and residual currents in Singapore regional waters     

Rama Rao Karri  Abhijit Badwe  Xuan Wang  Ghada El Serafy  Julius Sumihar  Vladan Babovic  Herman Gerritsen 《Ocean Dynamics》2013,63(1):43-61

Hydrodynamic models are commonly used for predicting water levels and currents in the deep ocean, ocean margins and shelf seas. Their accuracy is typically limited by factors, such as the complexity of the coastal geometry and bathymetry, plus the uncertainty in the flow forcing (deep ocean tide, winds and pressure). In Southeast Asian waters with its strongly hydrodynamic characteristics, the lack of detailed marine observations (bathymetry and tides) for model validation is an additional factor limiting flow representation. This paper deals with the application of ensemble Kalman filter (EnKF)-based data assimilation with the purpose of improving the deterministic model forecast. The efficacy of the EnKF is analysed via a twin experiment conducted with the 2D barotropic Singapore regional model. The results show that the applied data assimilation can improve the forecasts significantly in this complex flow regime.  相似文献   

Resistive wave breaking in the Earth's outer core     

Steven D. London 《地球物理与天体物理流体动力学》2013,107(5):397-411

The equations for an electrically conducting fluid in cylindrical coordinates are linearized assuming that the inertial terms in the momentum equation can be ignored (small Rossby number), and that the ratio of the Elsasser number and magnetic Reynolds number is one. After these assumptions, the governing equations are linearized about an ambient solution which vanishes at the the equator. Upon assuming large Elsasser and magnetic Reynolds number, the solutions to the linearized equations are approximated by wave trains having very short wave length (relative to the core radius) but which vary slowly (on a scale of the core radius). The period of the waves is much longer than a day but much shorter than the period of the slow hydromagnetic oscillations. These waves are found to be trapped in a region about the equator and away from the axis of rotation. The waves break at a latitudinal wave region boundary, in the sense that the waves become exponentially large in a boundary layer, having as an exponent some positive power of the large azimuthal wave number. This behavior is amplified as the Elsasser number becomes smaller while still remaining relatively large. Waves in more Earth-like parameter regimes are discussed briefly.  相似文献   

Stable carbon isotopic compositions of intact polar lipids reveal complex carbon flow patterns among hydrocarbon degrading microbial communities at the Chapopote asphalt volcano     

Florence Schubotz  Julius S. Lipp  Marcus Elvert  Kai-Uwe Hinrichs 《Geochimica et cosmochimica acta》2011,75(16):4399-3574

Seepage of asphalt forms the basis of a cold seep system at 3000 m water depth at the Chapopote Knoll in the southern Gulf of Mexico. Anaerobic microbial communities are stimulated in the oil-impregnated sediments as evidenced by the presence of intact polar membrane lipids (IPLs) derived from archaea and Bacteria at depths up to 7 m below the seafloor. Detailed investigation of stable carbon isotope composition (δ¹³C) of alkyl and acyl moieties derived from a range of IPL precursors with distinct polar head groups resolved the complexity of carbon metabolisms and utilization of diverse carbon sources by uncultured microbial communities. In surface sediments most of the polar lipid-derived fatty acids with phosphatidylethanolamine (PE), phosphatidylglycerol (PG) and diphosphatidylglycerol (DPG) head groups could be tentatively assigned to autotrophic sulfate-reducing bacteria, with a relatively small proportion involved in the anaerobic oxidation of methane. Derivatives of phosphatidyl-(N)-methylethanolamine (PME) were abundant and could be predominantly assigned to heterotrophic oil-degrading bacteria. Archaeal IPLs with phosphate-based hydroxyarchaeols and diglycosidic glyceroldibiphytanylglyceroltetraethers (GDGTs) were assigned to methanotrophic archaea of the ANME-2 and ANME-1 cluster, respectively, whereas δ¹³C values of phosphate-based archaeols and mixed phosphate-based and diglycosidic GDGTs point to methanogenic archaea. At a 7 m deep sulfate-methane transition zone that is linked to the upward movement of gas-laden petroleum, a distinct increase in abundance of archaeal IPLs such as phosphate-based hydroxyarchaeols and diglycosidic archaeol and GDGTs is observed; their δ¹³C values are consistent with their origin from both methanotrophic and methanogenic archaea. This study reveals previously hidden, highly complex patterns in the carbon-flow of versatile microbial communities involved in the degradation of heavy oil including hydrocarbon gases that would not have been evident from classical compound-specific isotope analyses of either bulk IPL or apolar lipid derivatives.  相似文献   

Boron in granitic magmas: stability of tourmaline in equilibrium with biotite and cordierite     

Michael B. Wolf  David London 《Contributions to Mineralogy and Petrology》1997,130(1):12-30

Experiments at 750 °C, 200 MPa_(H2O), a _(H2O)=1, and fO₂∼Ni-NiO established that the equilibrium among tourmaline, biotite, cordierite, and melt (± spinel, aluminosilicate, or corundum) occurs with ∼2 wt% B₂O₃ in strongly peraluminous melt with an aluminosity, measured by the parameter ASI, of >1.2. The experiments demonstrate the relationship of tourmaline stability to the activity product of the tourmaline components boron and aluminum, which are inversely related to one another. Tourmaline is unstable in metaluminous to mildly peraluminous melts (ASI <1.2) at 750 °C regardless of their boron content. For a given aluminosity, addition of components such as F requires a greater boron content of melt at this equilibrium. The stability of tourmaline increases with decreasing temperatures below 750 °C. At the inception of melting, tourmaline breaks down incongruently to assemblages containing crystalline AFM silicates (biotite, cordierite, garnet, sillimanite), aluminates (spinel, corundum), and B-enriched but Fe-Mg-poor melt. Granitic melts are likely to be undersaturated in tourmaline from the start of their crystallization, and their initial boron contents will be limited by the abundance of tourmaline in their source rocks. Quartzofeldspathic (gneissic, metapelitic) rocks that reached conditions of the granulite facies and still contain (prograde) tourmaline are rare, and probably have never yielded a partial melt. Most leucogranitic magmas will initially crystallize biotite, cordierite, or garnet, but not tourmaline. With crystallization, the Fe-Mg content of melt decreases, and the B₂O₃ content increases until the tourmaline-biotite and/or tourmaline-cordierite (or garnet) equilibria are attained. The B₂O₃ content of melt is buffered as long as these equilibria continue to operate, but low initial Fe-Mg contents of the magmas limit the quantity of boron that can be consumed by these reactions to <1 wt% B₂O₃. Normally, leucogranitic magmas contain insufficient Fe and Mg to conserve all boron as tourmaline and thus lose a large fraction of magmatic boron to wallrocks. Leucogranites and pegmatites with tourmaline as an early and only AFM silicate mineral probably contained >2 wt% B₂O₃ in their bulk magmas. Received: 6 August 1996 / Accepted: 21 July 1997  相似文献   

冠层内动量和物质吸收特征的数值研究     

雷孝恩  张时禹 《大气科学》1992,16(2):228-236

本文设计了一冠层(CL)和大气边界层(ABL)之间物质和动量交换的耦合模式,并对CL内风速、物质随高度分布和日变化作了数值模拟.结果表明,由大尺度扩散引起冠层低层的第二个风速极大和多极值的浓度分布,CL内湍流通量和物质浓度随高度减小而迅速降低,以及CL动量减小对浓度分布的重要影响,模式都能很好地描述,模拟结果与观测事实有好的一致性.利用浓度和温度廓线相似假设,导出了质量汇的经验关系.  相似文献   

The use of satellite observations for atmospheric radiation studies     

Julius London 《Theoretical and Applied Climatology》1962,12(1):64-77

Summary The problem of satellite observation of infrared radiation is studied in terms of geometric and spectral variation of atmospheric radiation. As an aid in interpretation of satellite observations, the anisotropy of out-going radiation at the top of the atmosphere and at the satellite level is computed for different atmospheric models and spectral regions to characterize radiation from the lower, middle, and high troposphere. It is shown that limb darkening is an extremely sharp property of the atmosphere as viewed from an orbiting satellite.

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Zusammenfassung Das Problem der Satellitenbeobachtungen der infraroten Strahlung wird in seiner Beziehung zu den geometrischen und spektralen ?nderungen der atmosph?rischen Strahlung untersucht. Die Anisotropie der ausgehenden Strahlung an der Obergrenze der Atmosph?re und in Satellitenh?he wird für verschiedene Atmosph?renmodelle und Spektralbereiche berechnet, um die Strahlung der niederen, mittleren und hohen Troposph?re zu charakterisieren und um die Deutung von Satellitenbeobachtungen zu erleichtern. Es wird gezeigt, da? die Randverdunklung ein besonders deutliches Kennzeichen der Atmosph?re ist, wie sie von einem kreisenden Satelliten gesehen wird.

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Résumé Le problème de l'observation, par satellite, des radiations infra-rouges est envisagé en fonction de la géométrie et des variations spectrales du champ de radiations atmosphériques. En vue de faciliter l'interprétation des observations obtenues au moyen de satellites, l'anisotropie du champ de radiations émergeantes est calculée à la limite supérieure de l'atmosphère et au niveau du satellite pour différents modèles atmosphériques et pour des régions spectrales caractérisant le champ de radiations de la basse, de la moyenne et de la haute troposphère. Nous démontrons que l'assombrissement du bord devrait être une propriété très caractéristique de notre atmosphère comme elle est observée d'un satellite artificiel.

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With 4 Figures

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It is a pleasure to dedicate this paper toDr. W. M?rikofer on the occasion of his 70th birthday and in recognition of his basic contributions to observations of atmospheric radiation.  相似文献   

Über einen neuen Versuch zur Anwendung statistischer Methoden in der Tektonik     

Julius Pia 《International Journal of Earth Sciences》1924,15(2):123-143

Ohne Zusammenfassung  相似文献   

A new Early–Middle Weichselian palaeoenvironmental record from a lacustrine sequence at Svirkanciai,Lithuania     

Jonas Satkunas  Alma Grigiene  Ilya V. Buynevich  Julius Taminskas 《Boreas: An International Journal of Quaternary Research》2013,42(1):184-193

The Middle Weichselian (OIS 4‐3) and the transition from Early to Middle Weichselian are the most problematic and disputed time intervals of the Late Pleistocene with regard to the palaeogeography of the Fennoscandian glaciations. The number of sites with sediments of Middle Weichselian age in the Baltic region is very limited. An extensive area (77 km²) of lacustrine sediments (sand, clay, silt with humus and interlayers of peat), under the relief‐forming Upper Weichselian till, was discovered in the vicinity of the Venta settlement, northwestern Lithuania, and named the Venta Palaeolacustrine Basin. The Svirkanciai outcrop (56°18′05″N, 22°53′00″E) (15 m in height) of this palaeobasin is composed of two sediment complexes of different genesis and age. The lower part consists of silt and very fine‐grained sand of lacustrine origin. According to palynological data, the lacustrine sediments accumulated under boreo‐arctic climatic conditions. The pollen records suggest that local vegetation was sparse forest with open areas. An Optically Stimulated Luminescence (OSL) date of the lacustrine sand yielded an age of >79±6 ka, which indicates that lacustrine conditions may have occurred during part of the Early Weichselian Odderade Interstadial (Jonionys 2). However, the palynological data from Svirkanciai suggest a Middle Weichselian age, possibly correlating with the Oerel Interstadial (Jonionys 3) 55 ka ago. No traces of early Middle Weichselian Schalkholz (Nemunas 2a) stadial glacial advance have been found in the Venta sections. This also suggests a Middle Weichselian age for the Svirkanciai lacustrine sediments.  相似文献   

Effect of sea water interaction on strontium isotope composition of deep-sea basalts     

E. Julius Dasch  Carl E. Hedge  Jack Dymond 《Earth and Planetary Science Letters》1973,19(2):177-183

Analyses of rim-to-interior samples of fresh tholeiitic pillow basalts, deuterically altered holocrystalline basalts, and older, weathered tholeiitic basalts from the deep sea indicate that ⁸⁷Sr/⁸⁶Sr ratios of the older basalts are raised by low temperature interaction with strontium dissolved in sea water. ⁸⁷Sr/⁸⁶Sr correlates positively with H₂O in these basalts; however, there is little detectable modification of the strontium isotope composition in rocks with H₂O contents less than 1%. The isotope changes appear to be a function of relatively long-term, low-temperature weathering, rather than high-temperature or deuteric alteration. Strontium abundance and isotopic data for these rocks suggest that strontium content is only slightly modified by interaction with sea water, and it is a relatively insensitive indicator of marine alteration. Average Rb-Sr parameters for samples of apparently unaltered basalt are: Rb= 1.11ppm; Sr= 132ppm; ⁸⁷Sr/⁸⁶Sr= 0.70247.  相似文献