High-frequency noise caused by wind in large ring laser gyroscope data     

A. Gebauer  K. U. Schreiber  T. Klügel  N. Sch?n  U. Ulbrich 《Journal of Seismology》2012,16(4):777-786

The large ring laser gyroscope at the Geodetic Observatory Wettzell provides unique data of the rotational component of seismic waves. Wind has been identified as a major source of noise at short periods below 5?min. Strong winds increase the level of detected background noise either through surface friction or through wind load on hill slopes. Since our G ring laser demonstrated a routinely achieved sensitivity for rotations of 10?picorad/s when averaged over 30?s, very small effects become detectable. Using a local finite element model and applying a digital terrain model with 25?m spatial resolution, the effect of local wind forces on tilt and horizontal rotations at the ring laser site was calculated. The transfer of forces by wind ram pressure or surface friction is strongly controlled by the resolution of the terrain model or the land use, respectively. The maximum deformation caused by real wind fields reaches a few tenths of nanorads for both tilt and horizontal rotation. While the tilts are too small to affect the ring laser measurements by a change in its inclination, the horizontal rotations can be detected by the ring laser if the signal builds up within a few seconds or tens of seconds. The comparison of the modelled rotation rate time series with measured ring laser data shows a reasonable agreement in amplitude and waveform, however the correction of the ring laser time series is limited by the crude sampling of the wind measurements.  相似文献   

Comparison of linear reconstructions for second-order finite volume schemes on polyhedral grids     

Robert Klöfkorn  Anna Kvashchuk  Martin Nolte 《Computational Geosciences》2017,21(5-6):909-919

Improved and enhanced oil recovery methods require sophisticated simulation tools to predict the injected flow pass together with the chemical reactions inside it. One approach is application of higher-order numerical schemes to avoid excessive numerical diffusion that is very typical for transport processes. In this work, we provide a first step towards higher-order schemes applicable on general polyhedral and corner-point grids typically used in reservoir simulation. We compare three possible approaches of linear reconstruction and slope limiting techniques on a variety of different meshes in two and three spatial dimensions and discuss advantages and disadvantages.  相似文献   

Search for orthorhombic or higher symmetry in rocks     

Karel Klíma  Zdeněk Pros  Reviewer K. Pěč 《Studia Geophysica et Geodaetica》1981,25(3):245-261

Summary The properties of quadrics of stress and strain, which were derived from the eigenvectors of the matrix of elastic constants, are analysed for a medium with orthorhombic or higher symmetry. It was found that the orientation of the axes of the quadrics can be employed to determine the crystallographic axes of the medium. This formalism derived for minerals is used for finding the axes of the internal symmetry of a rock for which we assume a distribution close to that of the orthorhombic system with a view to the spatial distribution of P-wave velocities.  相似文献   

Buchbesprechungen     

Jürg Bloesch  Peter Perret  F. Klötzli  F. Stössel 《Aquatic Sciences - Research Across Boundaries》1981,43(1):212-215

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On the problem of equal area block on a sphere     

Karel Klíma  Miloš Pick  Zdeněk Pros  Reviewer M. Burša 《Studia Geophysica et Geodaetica》1981,25(1):24-35

Summary A new untraditional way of dividing the sphere surface into an arbitrary number of equal area blocks by means of a spiral is proposed and its statistical properties are analysed.  相似文献   

Buchbesprechungen     

Elie Eichenberger  F. Klötzli  Kerry R. Kelts  H. R. Bürgi  F. Stössel  H. Jäckli 《Aquatic Sciences - Research Across Boundaries》1976,38(2):247-250

Ohne Zusammenfassung  相似文献   

Die Paläogeographische Auswertung der Altvulkanischen Bildungen zur Rekonstruktion der Korrelaten Sedimentationsräume im Bereich Späterer Abtragung     

Walther Klüpfel 《International Journal of Earth Sciences》1956,45(2):318-327

Ohne ZusammenfassungVortrag, gehalten am 14. März 1955 auf der Hauptversammlung der Geologischen Vereinigung in Mainz.  相似文献   

Experimentally Determined P-Wave Velocity Anisotropy for Rocks Related to the Western Bohemia Seismoactive Region     

Martínková  Marta  Pros  Zdeněk  Klíma  Karel  Lokajíček  Tomáš  Kotková  Jana 《Studia Geophysica et Geodaetica》2000,44(4):581-589

The elastic properties of granites from Western Bohemia which we measured and published earlier have been supplemented with measurements of olivine nephelinite from the same region and with data on lherzolitic xenolith from the vicinity of elezný Brod. The set of velocities measured under laboratory conditions has been compared with depth profiles suggested for the purpose of locating seismic swarm events which occur in this region. P-wave velocities were measured under pressures of up to 400 MPa. This pressure corresponds to depths of about 15 km for this region. The data were extrapolated for larger depths. Comparing laboratory measurements and seismic profiles, we can conclude that the rocks under study may be constituents of crust structures.  相似文献   

Variability in dryness and wetness in central Finland and the role of teleconnection patterns     

M. Irannezhad  A. Torabi Haghighi  D. Chen  B. Kløve 《Theoretical and Applied Climatology》2015,122(3-4):471-486

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Inverse modeling of natural tracer transport in a granite massif with lumped-parameter and physically based models: case study of a tunnel in Czechia     

Balvín  Aleš  Hokr  Milan  Šteklová  Klára  Rálek  Petr 《Hydrogeology Journal》2021,29(8):2633-2654

This study deals with numerical modelling of hydraulic and transport phenomena in granite of the Bohemian massif in Bedrichov, Czechia (Czech Republic). Natural tracers represented by stable isotopes δ¹⁸O and δ²H were collected at the tunnel outflow points and nearby catchment and their concentrations were monitored for seven years. The study compared transport simulations by a two-dimensional (2D) physically based model (advection-dispersion) developed in Flow123d software and a simpler lumped-parameter model, calculated with FLOWPC. Both variants were calibrated with UCODE software, either fitting the concentration data alone, or including the tunnel inflow rates in the case of the 2D model calibration (either in separate steps or within a single optimization problem). Since each of the models describes the tracer transport with different parameters, the models were compared based on the mean transit time as a postprocessed quantity. Besides this, two different options for processing the recharge data (input for both models) were evaluated. Calibration and data interpretation were possible for three of the four observed places in the tunnel, thus determining the depth limit of applicability of the stable isotopes. The estimates for discharge sampling at 25–35 m depth based on inverse modelling provide reasonable values of mean transit time (20–40 months) for the lumped parameter models, little revising the results of previous studies at the site. The resulting transport parameters of the advection-dispersion model (porosity and dispersivity) are in accordance with the hydrogeological structures present at the sampling sites.

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