Drought variability in eastern Mongolian Plateau and its linkages to the large-scale climate forcing   总被引：1，自引：0，他引：1  

Guang Bao  Yu Liu  Na Liu  Hans W. Linderholm 《Climate Dynamics》2015,44(3-4):717-733

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The role of intracontinental deformation in supercontinent assembly: insights from the Ribeira Belt,Southeastern Brazil (Neoproterozoic West Gondwana)   总被引：1，自引：0，他引：1       下载免费PDF全文

Vinícius T. Meira  Antonio García‐Casco  Caetano Juliani  Renato P. Almeida  Johann Hans D. Schorscher 《地学学报》2015,27(3):206-217

In this study, we challenge the multiple collision model for the tectonic evolution of the Neoproterozoic Ribeira Belt in Southeastern Brazil. New U–Pb SHRIMP data reveal Palaeoproterozoic (2153 ± 15 Ma) and Cryogenian (783 ± 6 and 768 ± 8 Ma) granitic rocks in the Embu Domain, and detrital zircon data of metasedimentary units from the Embu and Costeiro domains suggest a coherent tectonic evolution for the whole Ribeira Belt. Rather than by multiple collisions, these data are best explained by a simpler tectonic model involving continent (craton)‐volcanic arc collisions in the Dom Feliciano and Brasilia belts that led to intracontinental crustal thickening of the adjacent thinned hinterland (Ribeira Belt) at ~640–610 Ma, followed by widespread post‐collisional magmatism and rift‐related sedimentation at ~600–540 Ma. We suggest that intracontinental orogeny is a relevant process during supercontinent assembly, as illustrated here by the evolution of significant parts of the Brasiliano orogen.  相似文献   

Der geologische Lehrstuhl an der Universität Neuenburg in der Schweiz     

Hans Cloos 《International Journal of Earth Sciences》1941,32(3):389-393

Ohne Zusammenfassung  相似文献   

Tektonische Probleme am Nordrand des Harzes     

Hans Cloos 《International Journal of Earth Sciences》1916,7(7-8):314-329

Ohne ZusammenfassungVgl.Cloos, Eine neue Störungsform, (8).  相似文献   

A three-dimensional model study on processes of stratification and de-stratification in the Limfjord     

Richard Hofmeister  Hans Burchard  Karsten Bolding 《Continental Shelf Research》2009,29(11-12):1515-1524

Investigations on stratifying and de-stratifying processes in the Limfjord in Denmark, stretching from the North Sea at the western end to the Kattegat at the eastern end, were carried out. The forcing of the Limfjord is dominated by mean sea surface elevation and salinity gradients, diffuse freshwater supply, as well as episodic saline inflow events from the North Sea boundary. The physical regime of the Limfjord switches periodically from stratified to mixed conditions. In order to investigate the complexity of the system, a realistic three-dimensional high-resolution numerical model study was conducted for the year 2003. The results are based on, and compared to, available field data. A central subject of this study is the anomaly of potential energy as a measure for stratification. The stratifying and de-stratifying processes are identified as contributing terms in a dynamic equation for the potential energy anomaly. The comparison of model results and observations shows that the model has the capability of reproducing the observed physical regimes. Changes in the simulated stratification turn out to be a complex interaction of differential advection, heating and turbulent mixing in the central Limfjord.  相似文献   

Über das Gleitvermögen der Glimmer     

Hans Seifert 《Contributions to Mineralogy and Petrology》1948,1(4):486-504

Ohne Zusammenfassung  相似文献   

A comparison of gravity wave phase velocities calculated from the impedance equation and pressure data     

Hans Richner  Werner Nater 《地球物理与天体物理流体动力学》2013,107(1):15-26

Abstract

Marked oscillations in wind speed, wind direction and pressure with periods of between 5 and 15 minutes were recorded on a number of occasions and it is assumed that they were produced by atmospheric gravity waves. Gossard and Munk (1954) have shown that the phase velocity of a gravity wave can be calculated using wind and pressure fluctuation data from a single station by means of the “impedance equation”. It is also possible to measure the phase velocity of a gravity wave using an array of microbarovariographs. In this investigation, the phase velocity of gravity waves calculated using these two different methods are compared and the feasibility of deriving wave characteristics from single point measurements is discussed. The results show that, while in a few isolated cases the two velocities agree reasonably well, the application of the impedance equation to data from a single station is limited due to the superposition of local wind systems upon the wave-induced perturbations.  相似文献   

Rapid swing and spin of [deep] taut-wire-moored instruments     

Hans van Haren 《Deep Sea Research Part I: Oceanographic Research Papers》2010,57(7):909-917

Rapid ‘swing’, compass variations O(10°) in O(10 s), and ‘spin’, complete rotations around the vertical axis within a few minutes, are a concern of acoustic current meters moored in-line. Observations are used from fast sampling, at once per 1 and 30 s, instrumentation on deep-ocean moorings mainly outside surface wave and bottom boundary influences. Such instruments do not require a vane common to some historic mechanical current meters and they are often moored in a much easier to handle sub-surface buoy or mounting rack, without vanes. In their mountings they are nearly symmetric, so that they can spin freely in (turbulent; shear) flows. A comparison is made between noise levels of such free spinning instrumentation with those of instruments mounted in a fixed bottom-frame and with those of instruments equipped with a vane to one side. Typical spinning has a single rotation varying between 40 and 200 s. Spinning is shown to be highly binary: on or off. Its effects are found negligible on estimates of ocean currents, provided compass updates are adequate as in existing instrumentation. Acoustic noise is O(10) times larger than noise due to spinning. Some effects of spinning are noticed in the acoustic echo amplitude showing higher noise at frequencies >100 cpd, cycles per day. The character of this noise changes dramatically due to spinning. However, it is mainly in the ocean turbulence range and does not affect measurements of internal waves or periodic zooplankton motions.  相似文献   

Precise GPS Positioning by Applying Ionospheric Corrections from an Active Control Network   总被引：2，自引：1，他引：1  

Dennis Odijk  Hans van der Marel  Inseong Song 《GPS Solutions》2000,3(3):49-57

In this article, initial results are presented of a method to improve fast carrier phase ambiguity resolution over longer baselines (with lengths up to about 200 km). The ionospheric delays in the global positioning system (GPS) data of these long baselines mainly hamper successful integer ambiguity resolution, a prerequisite to obtain precise positions within very short observation time spans. A way to correct the data for significant ionospheric effects is to have a GPS user operate within an active or permanently operating network use ionospheric estimates from this network. A simple way to do so is to interpolate these ionospheric estimates based on the expected spatial behaviour of the ionospheric delays. In this article such a technique is demonstrated for the Dutch Active Control Network (AGRS.NL). One hour of data is used from 4 of the 5 reference stations to obtain very precise ionospheric corrections after fixing of the integer ambiguities within this network. This is no problem because of the relatively long observation time span and known positions of the stations of the AGRS.NL. Next these interpolated corrections are used to correct the GPS data from the fifth station for its ionospheric effects. Initial conclusions about the performance of this technique are drawn in terms of improvement of integer ambiguity resolution for this baseline. ? 1999 John Wiley & Sons, Inc.  相似文献   

The ROSAT–ESO Flux-Limited X-ray (REFLEX) galaxy cluster survey – VI. Constraints on the cosmic matter density from the KL power spectrum     

Peter Schuecker  Luigi Guzzo  Chris A. Collins  Hans Böhringer 《Monthly notices of the Royal Astronomical Society》2002,335(3):807-816

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