Untersuchungen über die Mächtigkeit von Schlickschichten mit Hilfe des Echographen     

Friedrich Schüler 《Ocean Dynamics》1952,5(5-6):220-231

Zusammenfassung Es wird über eine Methode zur Feststellung von Schlickmächtigkeiten, von Bodenschichtungen in weichem Boden und zur Ermittlung des Tiefenprofils des harten Untergrundes berichtet. An Hand von Echogrammen und im Vergleich mit Bodenproben wird die Methode diskutiert.

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Investigations into the thickness of mud layers with the aid of ultra sound records

Summary A method is discussed allowing to make investigations into the thickness of mud layers and to ascertain the stratification in soft ground as well as to reveal the relief of the solid substratum of the sea bottom. The method is explained by the aid of ultra sound records which are compared with bottom samples.

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Recherches sur l'épaisseur des couches vaseuses au moyen d'enregistrements d'ondes ultrasonores

Résumé Une méthode est exposée qui permet de déterminer qualitativement l'épaisseur de couches vaseuses, d'explorer la stratification dans des fonds meubles et de découvrir le relief du substratum solide du fond de la mer. Ensuite, cette méthode est illustrée à l'aide d'enregistrements d'ondes ultrasonores qui sont comparés avec des échantillons du fond de la mer.

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Handlotungen und Echolotungen in der Seevermessung geringer Wassertiefen in strömenden Gewässern — eine kritische Betrachtung     

Friedrich Schüler 《Ocean Dynamics》1952,5(1):6-21

Zusammenfassung Vergleichslotungen zwischen Echolot und Handlot führen zu einer mathematischen Ableitung der Handlotleinen-Kurve in strömenden Gewässern. Durch Einführung von zwei Vereinfachungen — Vernachlässigung des Lotleinen-Gewichts und Annahme der Konstanz der Strömungsgeschwindigkeit nach der Tiefe — wird theoretisch die Kettenlinie, praktisch eine Parabel ermittelt. Als bestimmend für den Parameter der Kettenlinie ergeben sich das Lotgewicht und der Staudruck auf die Lotleine. Aus einem praktischen Beispiel wird der Parameter entnommen, und es werden für diese Verhältnisse die für die Tiefenwerte bis 26 m zu erwartenden Fehlmessungen des Handlotes sowie die Größe der Ablagen der Lotbirne vom Lotpunkt berechnet. Für andere Werte der Strömungsgeschwindigkeit werden die Veränderungen auf die Ausbuchtung der Lotleine ebenfalls rechnerisch bestimmt und in Kurven dargestellt. Aus diesen Kurven ergeben sich zwangsläufig die größten Tiefen, die man bei verschiedenen Strömungsgeschwindigkeiten mit dem schweren Handlot vermessen darf; sie liegen bei v=1 m/sec bei 8 m, bei v=0,7 m/sec bei 12 m und bei v=0,5 m/sec bei 20 m Wassertiefe.Praktische Beispiele der Seevermessung aus der jüngsten Zeit zeigen deutlich die Notwendigkeit, zukünftig nur noch mit dem Echolot zu vermessen.

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A comment on the applicability of hand leads and echo sounders to surveying operations in flowing shallow waters

Summary From comparisons between hand-lead soundings and echo soundings in streaming waters the divergency of the lead line from the vertical is mathematically derived. In introducing two simplifications, i. e. in neglecting the weight of the lead line and in assuming the velocity of current to be constant at all depths, the catenary curve which practically speaking is a parabola, is theoretically ascertained. The weight of the lead and the dynamic pressuro of the water (the pressure as exerted on a jet and measured by it) are found to be decisive for the parameter of the catenary-curve. The parameter is derived from a practical example and, according to the conditions of same, the errors to be expected in sounding with the hand lead at depths up to 26 m (= 79 ft) as well as the divergency of the sounding lead from the vertical are calculated. The various degrees of the lead line's divergency caused by a greater or lesser intensity of the current are likewise calculated and represented by curves. These curves necessarily indicate the maximum depths that can be sounded with sufficient accuracy with the heavy hand lead (5 kilos) at different velocities of current; the approximate values are as follows: 8 m for 1,0 m/sec, 12 m for 0,7 m/sec, 20 m for 0,5 m/sec (or: 25 ft for 2,0 knots, 37 ft for 1,5 knots, 61 ft for 1,0 knot). As a result of practical experience in recent survey operations the echo sounder should be regarded as the only reliable instrument to be used in future surveying.

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Note critique sur l'applicabilité de la sonde au plomb-poisson et celle du sondeur acoustique aux levés hydrographiques effectués en faibles profondeurs dans les eaux courantes

Résumé Les comparaisons des sondages au plomb-poisson avec ceux effectués par écho permettent d'en dériver mathématiquement la courbe formée par la ligne de sonde dans des eaux courantes. En introduisant deux simplifications, c'est à dire en négligeant le poids de la ligne et en supposant que la vitesse de courant soit constante dans toutes les profondeurs on arrive à déterminer théoriquement la chaînette qui est en effet une parabole. Le paramètre est fonction du poids du plomb-poisson et celle de la poussée sensiblement horizontale sur le fil due au frottement du liquide. On se sert d'un exemple pratique pour en dériver le paramètre, pour calculer, dans les conditions de cet exemple, les sondages faux de la sonde au plomb-poisson dont il faut tenir compte dans les profondeurs jusqu'à 26 m, et pour déterminer la déviation entre le plomb au bout de la ligne et la verticale. Les diverses variations de la courbe, que la ligne subit et qui sont causées par d'autres valeurs de la vitesse de courant sont aussi calculées et représentées à l'aide des courbes. Ces courbes indiquent forcément les profondeurs permettant encore une précision suffisante du sondage au plombpoisson lourd (5 kg) aux différentes variations de la vitesse de courant. Ces maxima sont à peu près comme suit:v=1,0 m/sec à 8 m de profondeur,v=0,7 m/sec à 12 m de profondeur,v=0,5 m/sec à 20 m de profondeur. Des exemples pratiques offerts par des récentes levés hydrographiques prouvent que le sondeur acoustique doit être considéré comme le seul instrument assurant le précis levé hydrographique.

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Kurzer Bericht über die sedimentpetrographische Untersuchung zweier Lotkerne der Albatross-Expedition     

Dr. Friedrich Wilhelm Locher 《Contributions to Mineralogy and Petrology》1952,3(3):193-218

Ohne Zusammenfassung  相似文献   

Die Bedeutung der Atmosphärischen Wasserzirkulation für das Klima der Vorzeit     

Friedrich Schuh 《International Journal of Earth Sciences》1952,40(1):179-180

Ohne ZusammenfassungAuf der Heimfahrt von der Jahresversammlung der Geologischen Vereinigung in Köln, auf der das Thema Klima der Vorzeit behandelt wurde, drängte sich mir bei meinen rückschauenden Betrachtungen ein Klimafaktor auf, der bei der Tagung nicht erwähnt worden war und auch sonst wohl kaum in die Diskussion gezogen wurde, der mir aber doch beachtenswert scheint. So sollen die folgenden Zeilen gewissermaßen als nachträgliche Diskussionsbemerkung gewertet werden.  相似文献   

Stellenangebote und Stellengesuche     

Dr. Friedrich Schwarz 《International Journal of Earth Sciences》1931,22(5):352-352

Ohne Zusammenfassung  相似文献   

Scalar-Flux Similarity in the Layer Near the Surface Over Mountainous Terrain     

Eleni Sfyri  Mathias W. Rotach  Ivana Stiperski  Fred C. Bosveld  Manuela Lehner  Friedrich Obleitner 《Boundary-Layer Meteorology》2018,169(1):11-46

The scaled standard deviations of temperature and humidity are investigated in complex terrain. The study area is a steep Alpine valley, with six measurement sites of different slope, orientation and roughness (i-Box experimental site, Inn Valley, Austria). Examined here are several assumptions forming the basis of Monin–Obukhov similarity theory (MOST), including constant turbulence fluxes with height and the degree of self-correlation between the involved turbulence variables. Since the basic assumptions for the applicability of the MOST approach—horizontally homogeneous and flat conditions—are violated, the analysis is performed based on a local similarity hypothesis. The scaled standard deviations as a function of local stability are compared with previous studies from horizontally homogeneous and flat terrain, horizontally inhomogeneous and flat terrain, weakly inhomogeneous and flat terrain, as well as complex terrain. As a reference, similarity relations for unstable and stable conditions are evaluated using turbulence data from the weakly inhomogeneous and flat terrain of the Cabauw experimental site in the Netherlands, and assessed with the same post-processing method as the i-Box data. Significant differences from the reference curve and also among the i-Box sites are noted, especially for data derived from the i-Box sites with steep slopes. These differences concern the slope and the magnitude of the best-fit curves, illustrating the site dependence of any similarity theory.  相似文献   

Ejection-velocity distributions from impacts into coarse-grained sand     

Mark J. CINTALA  Lucinda BERTHOUD  Friedrich H RZ 《Meteoritics & planetary science》1999,34(4):605-623

Abstract— Velocities of ejecta from seven impacts of aluminum projectiles into coarse-grained sand have been measured with a laser-based apparatus that produces stroboscopic photographs of individual grains in ballistic flight. Speeds and angles of the majority of the ejecta can then be measured very precisely. There appears to be little effect of impact velocity on the functional relationship between the scaled, radial launch position and either the speed or angle of ejection; the seven experiments covered a range of impact velocities from 0.8 to 1.9 kms^—1. The measured ejection speeds follow power-law distributions, as predicted by dimensional analysis, but the angle of ejection is not constant throughout a given event as predicted. Indeed, the angle of ejection declines gradually with increasing radial distance from the impact point, but there are indications that the angle increases again as the position of the final crater's rim is approached. The exponents determined from scaled crater dimensions and ejection-speed distributions are substantially different. Although this might imply that assumptions used in the dimensional analysis are not valid, it is also possible that the coarse sand, whose component grains were comparable in dimension to the diameter of the impactors, instead presented a target that was more of an inhomogeneous aggregate of large fragments than a uniform, continuous medium.  相似文献   

Lead isotopes of the carbonate-hosted Kabwe, Tsumeb, and Kipushi Pb-Zn-Cu sulphide deposits in relation to Pan African orogenesis in the Damaran-Lufilian Fold Belt of Central Africa   总被引：5，自引：0，他引：5  

A. F. Kamona  J. Lévêque  G. Friedrich  U. Haack 《Mineralium Deposita》1999,34(3):273-283

Lead isotope ratios of galena from the carbonate-hosted massive sulphide deposits of Kabwe (Pb-Zn) and Tsumeb (Pb-Zn-Cu) in Zambia and Namibia, respectively, have been measured and found to be homogeneous and characteristic of upper crustal source rocks. Kabwe galena has average isotope ratios of ^206/204Pb = 17.997 ± 0.007, ^207/204Pb = 15.713 ± 0.010 and ^208/204Pb = 38.410 ± 0.033. Tsumeb galena has slightly higher ^206/204Pb (18.112 ± 0.035) and slightly lower ^207/204Pb (15.674 ± 0.016) and ^208/204Pb (38.276 ± 0.073) ratios than Kabwe galena. The isotopic differences are attributed to local differences in the age and composition of the respective source rocks for Kabwe and Tsumeb. The homogeneity of the ore lead in the two epigenetic deposits suggests lead sources of uniform isotopic composition or, alternatively, thorough mixing of lead derived from sources with relatively similar isotopic compositions. Both deposits have relatively high ²³⁸U/²⁰⁴Pb ratios of 10.31 and 10.09 for Kabwe and Tsumeb galenas, respectively. These isotope ratios are considered to be typical of the upper continental crust in the Damaran-Lufilian orogenic belt, as also indicated by basement rocks and Cu-Co sulphides in stratiform Katangan metasediments which have a mean μ-value of 10.25 ± 0.12 in the Copperbelt region of Zambia and the Democratic Republic of Congo (formerly Zaire). The ²³²Th/²⁰⁴Pb isotope ratios of 43.08 and 40.42 for Kabwe and Tsumeb suggest Th-enriched source regions with ²³²Th/²³⁵U (κ-values) of 4.18 and 4.01, respectively. Model isotopic ages determined for the Kabwe (680 Ma) and Tsumeb (530 Ma) deposits indicate that the timing of the mineralisation was probably related to phases of orogenic activity associated with the Pan-African Lufilian and Damaran orogenies, respectively. Galena from the carbonate-hosted Kipushi Cu-Pb-Zn massive sulphide deposit in the Congo also has homogeneous lead isotope ratios, but its isotopic composition is comparable to that of the average global lead evolution curve for conformable massive sulphide deposits. The μ (9.84) and κ (3.69) values indicate a significant mantle component, and the isotopic age of the Kipushi deposit (456 Ma) suggests that the emplacement of the mineralisation was related to a post-tectonic phase of igneous activity in the Lufilian belt. The isotope ratios (^206/204Pb, ^207/204Pb, ^208/204Pb) of the three deposits are markedly different from the heterogeneous lead ratios of the Katangan Cu-Co stratiform mineralisation of the Copperbelt as well as those of the volcanogenic Nampundwe massive pyrite deposit in the Zambezi belt which typically define radiogenic linear trends on lead-lead plots. The host-rock dolomite of the Kabwe deposit also has homogeneous lead isotope ratios identical to the ore galena. This observation indicates contamination of the Kabwe Dolomite Formation with ore lead during mineralisation. Received: 8 September 1997 / Accepted: 21 August 1998  相似文献   

Baroclinically-driven flows and dynamo action in rotating spherical fluid shells     

Radostin D. Simitev  Friedrich H. Busse 《地球物理与天体物理流体动力学》2017,111(5):369-379

The dynamics of stably stratified stellar radiative zones is of considerable interest due to the availability of increasingly detailed observations of Solar and stellar interiors. This article reports the first non-axisymmetric and time-dependent simulations of flows of anelastic fluids driven by baroclinic torques in stably stratified rotating spherical shells – a system serving as an elemental model of a stellar radiative zone. With increasing baroclinicity a sequence of bifurcations from simpler to more complex flows is found in which some of the available symmetries of the problem are broken subsequently. The poloidal component of the flow grows relative to the dominant toroidal component with increasing baroclinicity. The possibility of magnetic field generation thus arises and this paper proceeds to provide some indications for self-sustained dynamo action in baroclinically-driven flows. We speculate that magnetic fields in stably stratified stellar interiors are thus not necessarily of fossil origin as it is often assumed.  相似文献   

Late Pleistocene outburst floods from Issyk Kul,Kyrgyzstan?          下载免费PDF全文

Swenja Rosenwinkel  Angela Landgraf  Wolfgang Schwanghart  Friedrich Volkmer  Atyrgul Dzhumabaeva  Silke Merchel  Georg Rugel  Frank Preusser  Oliver Korup 《地球表面变化过程与地形》2017,42(10):1535-1548

Elevated shorelines and lake sediments surrounding Issyk Kul, the world's second largest mountain lake, record fluctuating lake levels during Quaternary times. Together with bathymetric and geochemical data, these markers document alternating phases of lake closure and external drainage. The uppermost level of lake sediments requires a former damming of the lake's western outlet through the Boam gorge. We test previous hypothesised ice or landslide dam failures by exploring possible links between late Quaternary lake levels and outbursts. We review and recompile the chronology of reported changes in lake site, and offer new ages of abandoned shorelines using ¹⁴C in bivalve and gastropod shells, and plant detritus, as well as sand lenses in delta and river sediments using Infrared Stimulated Luminescence. Our dates are consistent with elevated lake levels between ~45 ka and 22 ka. Cosmogenic ¹⁰Be and ²⁶Al exposure ages of fan terraces containing erratic boulders (>3 m) downstream of the gorge constrain the timing of floods to 20.5–18.5 ka, postdating a highstand of Issyk Kul. A flow‐competence analysis gives a peak discharge of >10⁴ m³ s^–1 for entraining and transporting these boulders. Palaeoflood modelling, however, shows that naturally dammed lakes unconnected to Issyk Kul could have produced such high discharges upon sudden emptying. Hence, although our data are consistent with hypotheses of catastrophic outburst floods, average lake‐level changes of up to 90 mm yr^–1 in the past 150 years were highly variable without any outbursts, so that linking lake‐level drops to catastrophic dam breaks remains ambiguous using sedimentary archives alone. This constraint may readily apply to other Quaternary lakes of that size elsewhere. Nonetheless, our reconstructed Pleistocene floods are among the largest reported worldwide, and motivate further research into the palaeoflood hydrology of Central Asia. Copyright © 2017 John Wiley & Sons, Ltd.  相似文献