排序方式： 共有15条查询结果，搜索用时 444 毫秒
1.
2.
H. Thiele 《Meteorology and Atmospheric Physics》1963,14(1):30-36
Zusammenfassung Orkan und Taifun werden als aus logarithmisch gekrümmten Austauschwalzen aufgehaut betrachtet. Sie bestehen aus doppelten Spiralen, entstanden beim Zusammentreffen zweier Luftströme: der im Zentrum röhrenförmig aufsteigenden tropischen Warmluft und einer zweiten horizontalen Komponente. Einige Merkmale, wie Art der Regenfälle, Art der elektrischen Entladungen, die Wolkenbilder und die Schleppe, passen zu dieser Vorstellung.
Mit 4 Textabbildungen 相似文献
Summary Hurricane and typhoon are considered as built up from logarithmically curved exchange cylinders. These bihelices are formed by the confluence of two air-currents: the tropical warm air in shape of a tube rising in the center and a second horizontal component. Some characteristics such as the shape of the rainfalls and of the electrical discharges, the species of clouds and the train are in agreement with this conception.
Résumé Ouragan et typhon sont regardés comme construits par cylindres échangeants — courbées dans un sens logarithmique. Ils se composent d'hélices doubles formées par le confluent de deux courants d'air: de l'air chaud tropical ascendant dans le centre sous forme d'un tube et d'une deuxième composante horizontale. Quelque caractéristiques comme la forme des chutes de pluie et des décharges électriques, les formations des nuages et la traîne sont en bon accord avec ce concept.
Mit 4 Textabbildungen 相似文献
3.
Bradley J. Griffin S. Thiele M. Richardson M.D. Thorne P.D. 《Oceanic Engineering, IEEE Journal of》2007,32(1):64-77
The U.S. Navy is supporting the research to develop and validate stochastic, time-dependent, mine burial prediction models to aid the tactical decision making process. This research requires continuous monitoring of both mine behavior during burial, and the near-field processes responsible for burial. A new instrumented mine has been developed that far exceeds the capabilities of the earlier optically instrumented mine in terms of the burial processes that can be measured. The acoustic-instrumented mine (AIM) utilizes acoustic transducers to measure burial and scour, localized flow rates, and sediment size and concentration in the water column. The AIM also includes sensors for measuring mine orientation and movement, as well as oceanographic information such as significant waveheights, wave period, and water temperature. Four AIMs were constructed and deployed during the Indian Rocks Beach (IRB, FL) and Martha's Vineyard Coastal Observatory (MVCO, Edgartown, MA) mine burial experiments. The results from the field experiments have proven that the sensor suite is viable in providing a wealth of data that are critical in understanding and modeling the complex subsequent burial process. 相似文献
4.
5.
Suzanne M. Prober Kevin R. Thiele Philip W. Rundel Colin J. Yates Sandra L. Berry Margaret Byrne Les Christidis Carl R. Gosper Pauline F. Grierson Kristina Lemson Tom Lyons Craig Macfarlane Michael H. O’Connor John K. Scott Rachel J. Standish William D. Stock Eddie J. B. van Etten Grant W. Wardell-Johnson Alexander Watson 《Climatic change》2012,110(1-2):227-248
The importance of ecological management for reducing the vulnerability of biodiversity to climate change is increasingly recognized, yet frameworks to facilitate a structured approach to climate adaptation management are lacking. We developed a conceptual framework that can guide identification of climate change impacts and adaptive management options in a given region or biome. The framework focuses on potential points of early climate change impact, and organizes these along two main axes. First, it recognizes that climate change can act at a range of ecological scales. Secondly, it emphasizes that outcomes are dependent on two potentially interacting and countervailing forces: (1) changes to environmental parameters and ecological processes brought about by climate change, and (2) responses of component systems as determined by attributes of resistance and resilience. Through this structure, the framework draws together a broad range of ecological concepts, with a novel emphasis on attributes of resistance and resilience that can temper the response of species, ecosystems and landscapes to climate change. We applied the framework to the world’s largest remaining Mediterranean-climate woodland, the ‘Great Western Woodlands’ of south-western Australia. In this relatively intact region, maintaining inherent resistance and resilience by preventing anthropogenic degradation is of highest priority and lowest risk. Limited, higher risk options such as fire management, protection of refugia and translocation of adaptive genes may be justifiable under more extreme change, hence our capacity to predict the extent of change strongly impinges on such management decisions. These conclusions may contrast with similar analyses in degraded landscapes, where natural integrity is already compromised, and existing investment in restoration may facilitate experimentation with higher risk?options. 相似文献
6.
Thiele A. Cadario E. Schulz K. Soergel U. 《Geoscience and Remote Sensing Letters, IEEE》2010,7(1):83-87
7.
R. Thiele I. Beccar B. Levi J. O. Nyström M. Vergara 《International Journal of Earth Sciences》1991,80(1):179-186
The Miocene Farellones Formation in central Chile (32°-35°S) is one of several up to 3000 mthick Tertiary volcanic sequences in the Central Andes with ash flows and intercalations of lacustrine sediments in their lower part, and intermediate to basic lavas and rhyolitic domes in their upper part. The Farellones rocks were probably deposited in a volcano-tectonic graben formed through a series of caldera collapses. This is suggested by (a) the fact that the formation frequently is delimited by normal faults towards which the subhorizontal strata pinch out and become upraised, indicating deposition during subsidence, (b) the huge volume of erupted acid magma and (c) a high paleothermal gradient of geothermal field type. Similar Tertiary volcanic sequences in northern Chile and central Peru probably also formed by eruptions in a caldera-graben setting. This setting and the geothermal field type of alteration make these sequences good prospecting targets for epithermal preciousmetal deposits.
Zusammenfassung Die miozäne Farellones-Formation im zentralen Chile (32°–35°S) ist eine von mehreren bis zu 3000 m mächtigen, tertiären vulkanischen Abfolgen der zentralen Anden, mit Ignimbriten und Zwischenlagerungen von lakustrinen Sedimenten im unteren, und mit intermediären bis basischen Laven und rhyolitischen Staukuppen im oberen Teil der Abfolgen. Die Gesteine der Farellones-Formation wurden wahrscheinlich in einem vulkano-tektonischen, durch eine Reihe von Caldera-Absenkungen entstandenen Graben abgelagert. Für diese Tatsache sprechen (a) häufige Begrenzung der Formation durch Normalverwerfungen gegen welche die subhorizontalen Schichten ausdünnen und aufgebogen werden, was Ablagerung während der Absenkung andeutet, (b) das große Volumen der sauren Vulkanite und (c) der hohe paläothermale Gradient von geothermalem Charakter. Ähnlich ausgebildete, tertiäre vulkanische Abfolgen im nördlichen Chile und zentralen Peru sind vermutlich ebenfalls durch Eruptionen in Caldera-Gräben gebildet worden. Aufgrund der tektonischen Ausbildung und des geothermalen Umwandlungstyp dürften diese Abfolgen für die Prospektion nach epithermalen Vorkommen von Edelmetallen von besonderem Interesse sein.
Resumen La Formación Farellones de Chile central (32°–35°S), deedadmiocena, es una de las muchas secuencias terciarias de más de 3000 m de espesor que existen en la alta cordillera de los Andes Centrales que contiene depósitos de flujos piroclásticos e intercalaciones de sedimentos lacustres en su parte inferior, y lavas intermedias a básicas y domos riolíticos en su parte superior. Las rocas de la Formación Farellones se depositaron, probablemente, en un graben volcano-tectónico formado a través de una serie de colapsos de calderas. Esta interpretación se basa en: (a) la frecuente delimitación de la formación por fallas normales contra las cuales los estratos subhorizontales se adelgazany se levantan, indicando depositación durante subsidencia, (b) el gran volumen de magma ácido extruido y (c) un gradiente paleotermal alto de tipo campo geotérmico. En el norte de Chile y en Perú central existen secuencias terciarias similares depositadas probablemente también en depresiones volcano — tectónicas tipo caldera — graben. Este marco tectónico y la alteración de tipo campo geotérmico, hace que éstas secuencias sean buenos blancos de prospección para depósitos epitermales de metales preciosos.
Farellones (32° – 35° ) , 3000 ., , . , , - , . : ) , , ; ) ; ) . , , , , . .. , .相似文献
8.
We discuss various strategies for parallelizing streamline simulators and present a single-phase shared memory implementation.
The choice of a shared memory programming model is motivated by its suitability for streamline simulation, as well as the
rapid advance of multicore processors, which are readily available at low-cost. We show that streamline-based methods are
easily parallelizable on shared memory architectures through their decomposition of the multidimensional transport equations
into a large set of independent 1D transport solves. We tested both a specialized explicit load balancing algorithm that optimizes
the streamline load distribution across threads to minimize the time that any of the threads are idle, and the dynamic load
balancing algorithms provided by OpenMP on the shared memory machines. Our results clearly indicate that built-in schedulers
are competitive with specialized load balancing strategies as long as the number of streamlines per thread is sufficiently
high, which is the case in field applications. The average workload per thread is nominally insensitive to workload variations
between individual streamlines, and any load balancing advantage offered by explicit strategies is not sufficient to overcome
associated computational and parallel overhead. In terms of the allocation of streamlines or streamline segments to threads,
we investigated both the distributed approach, in which threads are assigned streamline segments, and the owner approach,
in which threads own complete streamlines. We found that the owner approach is most suitable. The slight advantage that the
distributed approach has in terms of load balancing is not enough to compensate for the additional overheads. Moreover, the
owner approach allows straightforward re-use of existing sequential codes, which is not the case for the distributed approach
in case of implicit or adaptive implicit solution strategies. The tracing and mapping stages in streamline simulation have
low parallel efficiency. However, in real-field models, the computational burden of the streamline solves is significantly
heavier than that of the tracing and mapping stages, and therefore, the impact of these stages is limited. We tested the parallelization
on three shared memory systems: a 24 dual-core processor Sun SPARC server; an eight-way Sun Opteron server, representative
of the state-of-the-art shared memory systems in use in the industry; and the very recently released Sun Niagara II multicore
machine that has eight floating point compute units on the chip. We test a single-phase flow problem on three heterogeneous
reservoirs with varying well placements (this system gives the worst case scenario as the tracing and mapping costs are not
negligible compared to the transport costs). For the SPARC and Opteron system, we find parallel efficiencies ranging between
60 and 75 for the tracer flow problems. The sublinear speedup is mostly due to communication overheads in the tracing and
mapping stages. In applications with more complex physics, the relative contributions of these stages will decrease significantly,
and we predict the parallel performance to be nearly linear. On the Niagara II, we obtain almost perfect linear scalability
even for the single-phase flow problem thanks to the lowered communication costs on these architectures that have a shared
cache. This result is all the more satisfactory considering that future server designs will be akin to this system. 相似文献
9.
A. Ziad R. Gredel J. Aceituno J. Borgnino F. Hoyo A. Irbah F. Martin U. Thiele S. Pedraz 《Monthly notices of the Royal Astronomical Society》2005,362(2):455-459
The main atmospheric optical parameters have been measured at the Calar Alto Observatory simultaneously using the Generalized Seeing Monitor (GSM) and a Differential Image Motion Monitor (DIMM) during several nights in 2002 May. The temporal evolution of the seeing, the outer scale, the isoplanatic angle and the coherence time have been analysed. There is excellent agreement between the seeing measurements provided by the two instruments, particularly when the turbulence is slow. Indeed, the GSM measurements are corrected from the exposure time when the DIMM data were recorded for at least 5 ms. From almost three years of DIMM (at 5 m height above ground) data, a seeing of 0.92 arcsec with a standard deviation of 0.31 arcsec has been obtained for this site. The outer scale , the isoplanatic angle θ0 and the coherence time τ0 measured with the GSM are well fitted with log-normal distributions with median values of 22.9 m, 2.27 arcsec and 3.7 ms, respectively. 相似文献
10.
A comparison is drawn between jet propagation in molecular clouds and jets launched by galaxies in clusters. The biggest difference between the two types of jets is found in the density contrast. While the cocoon plasma in extragalactic jets has now been detected in X-rays, the corresponding cocoon gas for Herbig-Haro flows is barely visible. 相似文献