Gibt es ein Rannachkonglomerat?     

A. Hauser 《Mineralogy and Petrology》1948,1(2):107-133

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On the construction of dynamic systems from given integrals     

Rafael Ramirez  Natalia Sadovskaia 《Celestial Mechanics and Dynamical Astronomy》1995,63(2):149-170

In this communication we propose a new approach for studying a particular type of inverse problems in mechanics related to the construction of a force field from given integrals.An extension of the Danielli problem is obtained. The given results are applied to the Suslov problem, and illustrated in specific examples.  相似文献   

Some medium-path infrared observations of atmospheric boundary-layer structure during light wind     

R. K. Hauser  A. P. I. Eniiam  J. Griffin  M. Hawkins 《Boundary-Layer Meteorology》1977,11(4):397-418

Variations in water-vapour absorption were measured using a recently constructed field spectrophotometer, operated at a wavelength of 1.38 gm and with path lengths of 15 and 20 m. Observations were made 1 m above the ground near sunset, dawn, and during the morning destruction of nocturnal atmospheric stability. A diurnally consistent evolution of water-vapour turbulence regimes was observed. The presence of ordered events was revealed. These fluctuations indicate changes of vapour pressure, spatially averaged over the base-line, as large as about +7 mb in 4 s. Classification of light-wind observing conditions by using six classes of distinct non-random events appears possible. Such a classification system may reduce some of the characteristic scatter of micrometeorological results which arises during stable observing conditions or during comparison of real-world observing sites.On sabbatical leave (1975) at the Royal Military College of Science, Shrivenham, Wilts., England.  相似文献   

J.F. Larsen,C.A. Neal,J.R. Schaefer,A.M. Kaufman,and Zhong Lu: The 2008 phreatomagmatic eruption of Okmok volcano,Aleutian Islands,Alaska: chronology,deposits, and landform changes     

Natalia Pardo 《Bulletin of Volcanology》2015,77(8):1-3

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Acceleration strategies for elastic full waveform inversion workflows in 2D and 3D     

Jean Kormann  Juan E. Rodríguez  Miguel Ferrer  Albert Farrés  Natalia Gutiérrez  Josep de la Puente  Mauricio Hanzich  José M. Cela 《Computational Geosciences》2017,21(1):31-45

Full waveform inversion (FWI) is one of the most challenging procedures to obtain quantitative information of the subsurface. For elastic inversions, when both compressional and shear velocities have to be inverted, the algorithmic issue becomes also a computational challenge due to the high cost related to modelling elastic rather than acoustic waves. This shortcoming has been moderately mitigated by using high-performance computing to accelerate 3D elastic FWI kernels. Nevertheless, there is room in the FWI workflows for obtaining large speedups at the cost of proper grid pre-processing and data decimation techniques. In the present work, we show how by making full use of frequency-adapted grids, composite shot lists and a novel dynamic offset control strategy, we can reduce by several orders of magnitude the compute time while improving the convergence of the method in the studied cases, regardless of the forward and adjoint compute kernels used.  相似文献   

Optimization of photovoltaic solar power plant locations in northern Chile     

Anna Suuronen  Anssi Lensu  Markku Kuitunen  Rodrigo Andrade-Alvear  Natalia Guajardo Celis  Marcelo Miranda  Marcelo Perez  Jussi V. K. Kukkonen 《Environmental Earth Sciences》2017,76(24):824

The optimization of photovoltaic solar power plants location in Atacama Desert, Chile, is presented in this study. The study considers three objectives: (1) Find sites with the highest solar energy potential, (2) determine sites with the least impact on the environment, and (3) locate the areas which produce small social impact. To solve this task, multi-criteria decision analyses (MCDAs) such as analytical hierarchy process and ordered weighted averaging were applied in a GIS environment. In addition, survey results of social impacts were analyzed and included into the decision-making process, including landscape values. The most suitable sites for solar energy projects were found near roads and power lines throughout the study area. Large suitable areas were found also from central valley from Arica and Parinacota to the north edge of Atacama region. In Atacama region, most suitable sites were found in the Andes. On the contrary, Andes were also found to have high environmental values and scenically valuable landscapes. Moderate and low suitability were found on the coast, especially in Atacama region. Factors such as slope and distance to power lines and roads influenced largely the sensitivity analysis. Area of high suitability increased by 15% when distance to roads was excluded and 18% when distance to power lines or slope was removed. MCDA-GIS method was found to be useful and applicable to the optimization of solar power plant locations in northern Chile.  相似文献   

Regional climate simulations over South America: sensitivity to model physics and to the treatment of lateral boundary conditions using the MM5 model     

Silvina A. Solman  Natalia L. Pessacg 《Climate Dynamics》2012,38(1-2):281-300

In this study the capability of the MM5 model in simulating the main mode of intraseasonal variability during the warm season over South America is evaluated through a series of sensitivity experiments. Several 3-month simulations nested into ERA40 reanalysis were carried out using different cumulus schemes and planetary boundary layer schemes in an attempt to define the optimal combination of physical parameterizations for simulating alternating wet and dry conditions over La Plata Basin (LPB) and the South Atlantic Convergence Zone regions, respectively. The results were compared with different observational datasets and model evaluation was performed taking into account the spatial distribution of monthly precipitation and daily statistics of precipitation over the target regions. Though every experiment was able to capture the contrasting behavior of the precipitation during the simulated period, precipitation was largely underestimated particularly over the LPB region, mainly due to a misrepresentation in the moisture flux convergence. Experiments using grid nudging of the winds above the planetary boundary layer showed a better performance compared with those in which no constrains were imposed to the regional circulation within the model domain. Overall, no single experiment was found to perform the best over the entire domain and during the two contrasting months. The experiment that outperforms depends on the area of interest, being the simulation using the Grell (Kain–Fritsch) cumulus scheme in combination with the MRF planetary boundary layer scheme more adequate for subtropical (tropical) latitudes. The ensemble of the sensitivity experiments showed a better performance compared with any individual experiment.  相似文献   

Crustal properties from S-wave and gravity data along a seismic refraction profile in Romania     

V. Raileanu  A. Bala  F. Hauser  C. Prodehl  W. Fielitz 《Tectonophysics》2005,410(1-4):251-272

VRANCEA'99 is a seismic refraction line that was carried out in 1999 to investigate the deep structure and physical properties of the upper lithosphere of the southeastern Carpathians and its foreland. It runs from the city of Bacau to the Danube River, traversing the Vrancea epicentral area of strong intermediate-depth seismicity and the city of Bucharest.

Interpretation of P-wave arrivals led to a velocity model that displays a multi-layered crust with velocities increasing with depth. The range of P wave velocities in the sedimentary cover increases from N to S and a structuring of the autochthonous basement of the Moesian Platform is observed. The crystalline crust displays thickness variations, but at the same time the lateral velocity structure along the seismic line remains almost constant. An intra-crustal boundary separates an upper crust from the lower crust. Within the upper mantle a low velocity zone is detected at a depth of about 55-km.

The interpretation of observable S-waves resulted in a velocity model that shows the same multi-layered crust, with S-velocities increasing similarly with depth as the P-waves. The corresponding Poisson's ratio is highly variable throughout the crust and ranges from 0.20–0.35 for the sedimentary cover to 0.22–0.25 for the crystalline crust. The interpretation of the V_p, V_s and Poisson's ratio in petrological terms suggests a large variety of rocks from sand and clay to sandstone, limestone and dolomite within the sedimentary cover. Within the crystalline crust the most probably rock types are granite, granodiorite, granite–gneiss and/or felsic amphibolite–gneiss in the upper part and gneiss and /or amphibolite in the lower part.

Based on the 2-D seismic velocity model, a density model is developed. Density values are assigned to each layer in agreement with the P-wave velocity model and with values accepted for the geological units in the area. After several iterations a good fit between the computed and observed Bouguer anomalies was obtained along the seismic line.  相似文献   

2.5D seismic velocity modelling in the south-eastern Romanian Carpathians Orogen and its foreland     

Andrei Bocin  Randell Stephenson  Ari Tryggvason  Ionelia Panea  Victor Mocanu  Franz Hauser  Liviu Matenco 《Tectonophysics》2005,410(1-4):273-291

The DACIA-PLAN (Danube and Carpathian Integrated Action on Processes in the Lithosphere and Neotectonics) deep seismic reflection survey was performed in August–September 2001, with the objective of obtaining new information on the deep structure of the external Carpathians nappe system and the architecture of the Tertiary/Quaternary basins developed within and adjacent to the Vrancea zone, including the rapidly subsiding Focsani Basin. The DACIA-PLAN profile is about 140 km long, having a roughly WNW–ESE direction, from near the southeast Transylvanian Basin, across the mountainous south-eastern Carpathians and their foreland to near the Danube River. A high resolution 2.5D velocity model of the upper crust along the seismic profile has been determined from a tomographic inversion of the DACIA-PLAN first arrival data. The results show that the data fairly accurately resolve the transition from sediment to crystalline basement beneath the Focsani Basin, where industry seismic data are available for correlation, at depths up to about 10 km. Beneath the external Carpathians nappes, apparent basement (material with velocities above 5.8 km/s) lies at depths as shallow as 3–4 km, which is less than previously surmised on the basis of geological observations. The first arrival travel-time data suggest that there is significant lateral structural heterogeneity on the apparent basement surface in this area, suggesting that the high velocity material may be involved in Carpathian thrusting.  相似文献   

New insight into the crust and upper mantle structure under Alaska   总被引：1，自引：0，他引：1  

Cheng Qi  Dapeng Zhao  Yong Chen  Natalia A. Ruppert 《Polar Science》2007,1(2-4):85-100

To better understand the seismic structure of the subducting Pacific plate under Alaska, we determined the three-dimensional P-wave velocity structure to a depth of approximately 200 km beneath Alaska using 438,146 P-wave arrival times from 10,900 earthquakes. In this study an irregular grid parameterization was adopted to express the velocity structure under Alaska. The number of grid nodes increases from north to south in the study area so that the spacing between grid nodes is approximately the same in the longitude direction. Our results suggest that the subducting Pacific slab under Alaska can be divided into three different parts based on its geometry and velocity structure. The western part has features similar to those in other subduction zones. In the central part a thick low-velocity zone is imaged at the top of the subducting Pacific slab beneath north of the Kenai Peninsula, which is believed to be most likely the oceanic crust plus an overlying serpentinized zone and the coupled Yakutat terrane subducted with the Pacific slab. In the eastern part, significant high-velocity anomalies are visible to 60–90 km depth, suggesting that the Pacific slab has only subducted down to that depth.  相似文献