Nocturnal drainage flow on simple slopes     

T. W. Horst  J. C. Doran 《Boundary-Layer Meteorology》1986,34(3):263-286

Observations of nocturnal slope flow have been made at two sites with quite different topography and vegetation. In both cases, continuous measurements of wind and temperature profiles were made from towers that extended through the depth of the katabatic flow. At the simpler site, which approximates a tilted plane, three towers were located at different distances down the slope to measure the development of slope flow with downslope distance.Slope flow depth, downslope wind speed, and temperature deficit are found to change with downslope distance at rates that are consistent with the predictions of Manins and Sawford's (1979) layer-averaged model of slope flow, while measured entrainment rates are found to be comparable to those predicted by Ellison and Turner's (1959) laboratory experiments. The depth of slope flow is found to be roughly 0.05 times the vertical drop from the top of the slope, a relationship that also follows from combining Manins and Sawford's model and Ellison and Turner's laboratory data. Analysis of the wind spectra and a simple numerical model suggest that the turbulent kinetic energy profiles in slope flow are dependent on the speed and direction of the ambient wind and can differ substantially from those found over flat terrain. At the more complex of the two measurement sites, the occurrence of slope flow was found to correlate well with a dimensionless number 5 that is a function of the ridge-top wind speed and of the strength and depth of the inversion and that is an estimate of the ratio of the buoyancy deficit to the external horizontal pressure gradient.Prepared for the U.S. Department of Energy under Contract DE-AC06-76RLO 1830  相似文献   

Deep structure of the bohemian massif from phase velocities of Rayleigh and Love waves     

Erhard Wielandt  Andreas Sigg  Axel Plešinger  Josef Horálek  Reviewer K. Pěč 《Studia Geophysica et Geodaetica》1987,31(1):1-7

Summary Phase velocities of Rayleigh and Love waves have been measured between the broadband seismic stations KHC (Kaperské Hory, South Bohemia) and KSP (Ksi, Lower Silesia), a profile that nearly coincides with the Interactional DSS Profile VII. The data for both wave types were separately inverted into models of shear-wave velocity versus depth. Novotný's model KHKS 82[1] for the DSS Profile VII was used as a start model. While the crustal section of Novotný's model is compatible with both of our data sets, our Rayleigh-wave data require smaller shear-wave velocities, on the average by 0.24 km/s, in the top 180 km of the mantle. The average difference between Novotný's model and our Love-wave model in that depth range is only 0.06 km/s. If our identification of the observed Love waves as the fundamental mode is correct, this result indicates the presence of polarization anisotropy in the uppermost mantle.

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Transmission electron microscopic study of antiphase domains in CaAl2Ge2O8-Feldspar     

Wolfgang Friedrich Müller  Yusof Vojdan-Shemshadi  Horst Pentinghaus 《Physics and Chemistry of Minerals》1987,14(3):235-237

Transmission electron microscopic study of synthetic CaAl₂Ge₂O₈-feldspar revealed two types of antiphase domains: type “b”-antiphase domains with the displacement vector 1/2 [110] and type “c”-antiphase domains with the displacement vector 1/2 [111]. The “b”-domains were on the order of 0.1 μm in size, while the “c”-domains displayed wall to wall distances mostly between 0.1 and 1 μm. The formation of the two types of antiphase domains is due to reductions in translational symmetry associated with the phase transitions \(C\bar 1 \to I\bar 1 \to P\bar 1\) . The antiphase domain textures of CaAl₂Ge₂O₈-feldspar are very similar to the textures found in natural and synthetic anorthite, CaAl₂Si₂O₈.  相似文献   

Military Emissions, Armed Conflicts, Border Changes and the Kyoto Protocol     

Axel Michaelowa  Tobias Koch 《Climatic change》2001,50(4):383-394

The impacts of military activities in peacetime, military action and territorial changes on greenhouse gas emission commitments of nations under the Kyoto Protocol are analysed. We propose rules and institutional responsibilities to deal with the repercussions of such changes on markets in emission permits and national commitments aiming at prevention of serious distortions.  相似文献   

Desalinization of running waters: III. Changes in the structure of diatom assemblages caused by a decreasing salt load and changing ion spectra in the river Wipper (Thuringia, Germany)     

Horst Ziemann  Ludwig Kies  Claus-Jürgen Schulz   《Limnologica》2001,31(4):257-280

Salt-loaded effluents were introduced into the river Wipper during the mining period for almost a century. Beginning with the year 1990, the waste water load was strongly reduced due to the termination of the potash industry. Prior to 1990, monthly means of the chloride concentrations at times exceeded 6,000 mg l⁻¹ in the strongly polluted sections. Maximum concentrations reached twice these values. Up to 1998, mean annual chloride concentrations decreased to values below 2,000 mg l⁻¹. This led to more balanced fluctuations in salinity which had been pronounced before, depending on discharge and short-term changes in production. Similarly, the physiologically adverse ion conditions improved due to decrasing potassium and increasing calcium proportions.

In 1963/64, 1986 and 1998, samples of epilithic, epiphytic and epipsammic diatoms were taken at locations of different salinities along the river and examined for the effects of the salinization on the structure of the diatom assemblages. These structures changed in dependence on salinity. Increasing salt concentrations coincided with decreasing oligohalophilic and increasing mesohalophilic and polyhalophilic species numbers. Above a chloride concentration of about 3,000 mg l⁻¹, the proportion of the latter exceed that of the former (halobion index > 50). Corresponding to different conditions of salinization along the river, characteristic diatom assemblages occur differring from each other and which are specific for the river section. Spring and autumn aspects of the diatom assemblages show also salt-dependent differences. The assemblages found in 1998 after decrease of salinization have changed markedly in comparison to those from 1963/64 and 1986. Halobiontic species predominating formerly occurred only occasionally or not at all. They were replaced by oligohalobic-indifferent forms.

An ecological assessment of the changes was performed based on the halobion index calculated from all the samples. For the strongly salinized section of the river Wipper, a shift from -mesohalobic/polyhalobic conditions in 1963/64 and 1986 to -oligohalobic/β-mesohalobic conditions in 1998 was found. However, constant -oligohalobic conditions are still not given. With regard to the transition from -oligohalobic (limnetic) to β-mesohalobic (brackish) conditions, a maximum chloride concentration of 600 mg l⁻¹ was found. To guarantee -oligohalobic conditions, a maximum chloride concentration of 400 mg l⁻¹ should not be exceeded.  相似文献   

Reviews Monitoring the Comprehensive Nuclear-Test-Ban Treaty: Source Location,edited by Frode Ringdal and Brian L. N. Kennett. Birkhäuser Verlag Basel-Boston-Berlin, 2001, Reprint from Pure and Applied Geophysics (PAGEOPH), Volume 158 (2001), No.1/2, 428 pages     

Plešinger  Axel 《Studia Geophysica et Geodaetica》2001,45(3):325-325

Studia Geophysica et Geodaetica -  相似文献   

Die Kreide in der Zentralkordillere östlich von Lima (Peru,Südamerika)     

Prof. Dr. Axel Von Hillebrandt 《International Journal of Earth Sciences》1970,59(3):1180-1203

Lower and Upper Cretaceous sediments were investigated in the Peruvian Central Cordillera. As in the western facies of Central and Northern Peru, the Goyllarisquisga Group is subdivided into several lithologically different formations, in which sediments were transported from east to west. The area of investigation is situated west of the facies boundary between Marañon geanticline and West Peruvian trough; this indicates that the boundary continues south and does not follow the line Celendin-Rio Palanga as suggested byWilson. The limestones and dolomites of the Santa Formation were deposited in shallow water, possibly with intermittent subaerial exposure. The sandstone of the Farrat Formation are interpreted to be sediments of a west-east transgression; vertically they grade into the limestones of the Pariahuanca-Formation. Facies and thickness of the Chulec and Pariahuanca-Formation are little different from those in neighbouring areas. During deposition of the thick Jumasha Formation, the differences are much more significant, and only comparison with Northwest Peru shows some agreement.  相似文献   

Entwurf von Photoelektrischen Rückkopplungsverstärkern mit Vorgeschriebenen Übertragungseigenschaften     

Axel Plešinger 《Studia Geophysica et Geodaetica》1968,12(1):50-55

Приводится описание фотокомпенсационного усилителя на полупроводниках, предназначенного для усиления слабых выходных сигналов пассивных преобразователей геофизических величин. Шумовые помехи отнесенные к входу усилителя порядка 10^?8 в или 10^?10 а в диапазоне частот 0,01–20Гц. Описывается новый метод, который позволяет создать фотокомпенсационные усилители напряжения или тока с заранее заданными передаточными свойствами (заданной амплитудной или фазовой частотной характеристкой, заданным быстродействием и т.п.). Возможности использования этого метода демонстрируются на двух практических примерах.  相似文献   

Anwendung Elektronischer Filtersysteme zur Identifizierung von Schwachen Seismischen Signalen     

Axel Plešinger 《Studia Geophysica et Geodaetica》1967,11(4):460-464

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Die Rotsedimentation im Saar-Pfälzischen Rotliegenden     

Horst Falke 《International Journal of Earth Sciences》1955,43(2):350-351

Ohne Zusammenfassung  相似文献