Friedrich Teller-Fonds     

Otto Ampferer 《International Journal of Earth Sciences》1915,6(1-2):103-103

Ohne Zusammenfassung  相似文献   

DIE TECHNISCHE UND WIRTSCHAFTLICHE BEDEUTUNG DER GLETSCHER / The Role of Glaciers in the Economy and Technical Development of Alpine Countries     

Otto LANSER Dipl. Ing. Dr. techn. 《水文科学杂志》2013,58(1):83-93

English Summary

In former times the inhabitants of alpine regions looked upon glaciers as an uncanny and dangerous realm which they avoided as far as possible. It was only around the middle of the 18th Century that man became gradually aware of the beauty of the mountains, and approximately at the same time science started to take an interest in glaciers. Most of the questions raised in this field have been solved since. However, even in our times it is not sufficiently well known that glaciers, which are responsible for the characteristics of the regime of alpine rivers, are interesting not only from the point of view of physical geography, but are also of great importance for the economy and technical development of alpine countries.

Torrents which are fed by the melted ice, carry great quantities of water at periods when other streams frequently run dry. Nevertheless, in the terms of hydraulic power economy, it would be an over simplification to consider glaciers as reservoirs. It must not be forgotten, that in the Alps precipitation is highest during the summer months, and consequently that rivers carry more water during that season than during any other period of the year. The presence of glaciers adds to the extreme situation, and therefore the equalisation of seasonal differences in the runoff of glaciers necessary for power economy requires more storage capacity than is needed for catchment areas without glaciers.

On the other hand, there are also arid zones in the Alps, where conditions are entirely different. I am thinking of the deep valleys, running east to west, which are screened from rain by high mountain ranges, as for instance in the Wallis, the Vintschgau, parts of Western Tyrol and the Engadine. In these valleys it is particularly the slopes open to the south and exposed to constant insolation which show the typical characteristics and vegetation of arid zones. Precipitation during the growing season is often far less than the 600mm which is considered as the minimum needed for most types of cultivation, so much so that artificial irrigation has been practised for many generations. Whenever possible, the aqueducts, often very primitive, are fed by the glacier runoff of the large mountain massifs which never run dry. In some parts of the Wallis and in the South and West Tyrol, the water had to be conducted long distances and across difficult terrain; the construction of these primitive aqueducts was therefore a truly difficult task, as financial and technical resources available for that purpose were very inadequate.

This additional water-supply produced by glaciers in summer has a very definite effect on the large rivers rising in the Alps and flowing down in all directions, to name a few of them, the Rhine, the Inn, the Drave, the Rhône, the Adige etc. Not a single one of them has a low water level record in summer equal to that of the Weser or the Elbe and many other rivers of Central Europe which are not fed by glaciers. This low water level in summer has naturally a very detrimental effect on the navigation of rivers, and also on their capacity to replenish ground-water resources. The abundance of glacier runoff assures a fairly steady supply of water to the first mentioned rivers even in their lower courses, a fact which is of special importance for hydraulic economy in general and for hydraulic energy economy in particular. The rich potential of hydraulic energy in Jugoslavia, for instance, suffers from the fact that the quantity of water carried by the karst-rivers is considerably smaller in summer than it is in winter. The river Drave with its tributaries fed by glacier runoff from the Alps in Carynthia and East Tyrol, is practically the only river in Jugoslavia used to a considerable extent for the production of hydraulic power. It carries even more water in summer than during other seasons. This river, which serves to equalise the seasonal production of energy is therefore most valuable for the power economy of the country.

Short-term changes in the size of glaciers which are the subject of our present symposium, are causing the development of glacier lakes of which there exist several types. Most dangerous are those in larger valleys, caused by the tongue of a side glacier forming a dam, for instance here in the Ötztal Alps, at the Gurgler and at the Rofener Eissee near Vent. Other lakes develop in the basins left behind by the tongues of former glaciers. Water suddenly released from glacier lakes due to a breach of the ice or moraine dam, has frequently been the cause of terrible catastrophes. Attempts have therefore been made to protect the valleys against floods by the construction of flood reservoirs suitably situated below the glacier. An example of this type is the reservoir dam which the Austrian torrent-control authorities constructed in the Martellvalley (South Tyrol) in 1898/99 to prevent damage from an eventual breach in the banks of a glacier lake which had developed. Nowadays the large reservoirs constructed for hydro-electric power provide even greater protection.

Reservoirs for power plants in the Alps, which are created by the construction of large dams, require the existence of basins hollowed out by former glaciers during a long geological period. Outside of the glaciated areas, such basins can generally be created only by artificially blocking up a river-valley. This type of reservoir can be easily distinguished from that described above by its entirely different outline.

It must finally be remembered that the large load of sediment carried by glacial rivers has its economic and technical problems. Although it will probably take centuries to fill up the largest hydro-electric reservoirs, or even to considerably reduce their storage capacity, there are many smaller lakes in which this development will take no more than decades. Deposits of mud, for instance in the reservoir of the Margaritze, in the “Tauernfraftwerke” area had, after a mere decade accumulated to the extent that the power-plant administration had to install a floating suction dredger to remove at least part of the sediment. In this connection it was, however, important not to overload the river downstream with mud to such a degree as to cause damage to the fish population. Careful observation was needed to find out to what extent the river was able to cope with the artificial inflow of mud, and to follow the dispersion of the peak values of the suspesion load.

Nowadays waters destined for the generation of hydro-electric power are collected at the highest possible altitudes. An interesting example of the application of modern methods of this type is the collection of the runoff from beneath the Brandner Ferner in the Silvretta from where it is conveyed to the Lünersee. As a water intake on the surface was impossible due to the difficult terrain, a tunnel had to be driven through the rock bed of the glacier and there, immediately underneath it, in an ice cave, the water flows into a cage consisting of strong steel girders. This cage retains the large bolders, while the water from the bottom of the glacier runs off into the tunnel.  相似文献   

Populus nigra L. establishment and fluvial landform construction: biogeomorphic dynamics within a channelized river          下载免费PDF全文

Dov Corenblit  Johannes Steiger  Gaspard Charrier  José Darrozes  Virginia Garófano‐Gómez  Alexandre Garreau  Eduardo González  Angela M. Gurnell  Borbála Hortobágyi  Frédéric Julien  Luc Lambs  Sébastien Larrue  Thierry Otto  Erwan Roussel  Franck Vautier  Olivier Voldoire 《地球表面变化过程与地形》2016,41(9):1276-1292

Populations of the riparian pioneer species Populus nigra L. which establish on alluvial bars within river channels modulate sediment dynamics and fluvial landforms. Dense cohorts of P. nigra have colonized gravel point bars along the channelized River Garonne, France, during the last 20 years and have enhanced the vertical, lateral and longitudinal development of the bars. For this period, the geomorphic characteristics of two wooded point bars on this laterally stable river are closely linked to the spatial distribution and intensity of establishment and resistance of different cohorts of P. nigra. Furthermore, P. nigra colonization dynamics were controlled by engineer effects of this same species. This relationship is illustrated by a significant correlation between key geomorphic and biological variables measured in situ and characterized with a set of four aerial photographs taken between 2000 and 2010. The development of wooded point bars, which are discrete biogeomorphic units, over the studied period, appear to result from a specific biogeomorphic positive feedback of matter aggregation and vegetation establishment related to sediment trapping and stabilization by pioneer engineer plants. We propose a conceptual model of biogeomorphic unit construction for channelized, lateral stable rivers. We consider the resultant biogeomorphic units as functional from an ecological point of view because P. nigra enhances at the cohort scale (i) its own inherent capacity to resist hydrogeomorphic disturbances, and (ii) its resilience capacity as a result of successful colonization, especially downstream of mature poplar stands. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

Holocene circum-Mediterranean vegetation changes: Climate forcing and human impact   总被引：2，自引：0，他引：2  

Guy Jalut  Jean Jacques Dedoubat  Michel Fontugne  Thierry Otto 《Quaternary International》2009,200(1-2):4

The Mediterranean climate and its variability depend on global-scale climate patterns. Close correlations appear when comparing Holocene palaeoenvironmental data (lake levels, fluvial activity, Mediterranean surface temperature and salinity, marine sedimentation) with the main stages of the history of the circum-Mediterranean vegetation. They indicate an evolution of the Mediterranean biome controlled by the climate and emphasize the teleconnections between the climate of the Mediterranean area and the global climatic system. In the circum-Mediterranean area, the Holocene can be divided into three periods: a lower humid Holocene (11 500–7000 cal BP) interrupted by dry episodes; a transition phase (7000–5500 cal BP) during which occurred a decrease in insolation as well as the installation of the present atmosphere circulation in the northern hemisphere; and an upper Holocene (5500 cal BP—present) characterized by an aridification process. Throughout the Holocene, humans used and modified more or less strongly the environment but the climatic changes were the determining factors of the evolution of the Mediterranean biome. Societies had to adapt to natural environmental variations, their impact on the environment increasing the ecological consequences of the global changes.  相似文献   

Mineralogy and chemistry of Rumuruti: The first meteorite fall of the new R chondrite group     

H. Schulze  A. Bischoff  H. Palme  B. Spettel  G. Dreibus  J. Otto 《Meteoritics & planetary science》1994,29(2):275-286

Abstract— The Rumuruti meteorite shower fell in Rumuruti, Kenya, on 1934 January 28 at 10:43 p.m. Rumuruti is an olivine-rich chondritic breccia with light-dark structure. Based on the coexistence of highly recrystallized fragments and unequilibrated components, Rumuruti is classified as a type 3–6 chondrite breccia. The most abundant phase of Rumuruti is olivine (mostly Fa_～39) with about 70 vol%. Feldspar (～14 vol%; mainly plagioclase), Ca-pyroxene (5 vol%), pyrrhotite (4.4 vol%), and pentlandite (3.6 vol%) are major constituents. All other phases have abundances below 1 vol%, including low-Ca pyroxene, chrome spinels, phosphates (chlorapatite and whitlockite), chalcopyrite, ilmenite, tridymite, Ni-rich and Ge-containing metals, kamacite, and various particles enriched in noble metals like Pt, Ir, arid Au. The chemical composition of Rumuruti is chondritic. The depletion in refractory elements (Sc, REE, etc.) and the comparatively high Mn, Na, and K contents are characteristic of ordinary chondrites and distinguish Rumuruti from carbonaceous chondrites. However, S, Se, and Zn contents in Rumuruti are significantly above the level expected for ordinary chondrites. The oxygen isotope composition of Rumuruti is high in δ¹⁷O (5.52 ‰) and δ¹⁸O (5.07 ‰). Previously, a small number of chondritic meteorites with strong similarities to Rumuruti were described. They were called Carlisle Lakes-type chondrites and they comprise: Carlisle Lakes, ALH85151, Y-75302, Y-793575, Y-82002, Acfer 217, PCA91002, and PCA91241, as well as clasts in the Weatherford chondrite. All these meteorites are finds from hot and cold deserts having experienced various degrees of weathering. With Rumuruti, the first meteorite fall has been recognized that preserves the primary mineralogical and chemical characteristics of a new group of meteorites. Comparing all chondrites, the characteristic features can be summarized as follows: (a) basically chondritic chemistry with ordinary chondrite element patterns of refractory and moderately volatile lithophiles but higher abundances of S, Se, and Zn; (b) high degree of oxidation (37–41 mol% Fa in olivine, only traces of Fe, Ni-metals, occurrence of chalcopyrite); (c) exceptionally high Δ¹⁷O values of about 2.7 for bulk samples; (d) high modal abundance of olivine (～70 vol%); (e) Ti-Fe³⁺?rich chromite (～5.5 wt% TiO₂); (f) occurrence of various noble metal-rich particles; (g) abundant chondritic breccias consisting of equilibrated clasts and unequilibrated lithologies. With Rumuruti, nine meteorite samples exist that are chemically and mineralogically very similar. These meteorites are attributed to at least eight different fall events. It is proposed in this paper to call this group R chondrites (rumurutiites) after the first and only fall among these meteorites. These meteorites have a close relationship to ordinary chondrites. However, they are more oxidized than any of the existing groups of ordinary chondrites. Small, but significant differences in chemical composition and in oxygen isotopes between R chondrites and ordinary chondrites exclude formation of R chondrites from ordinary chondrites by oxidation. This implies a separate, independent R chondrite parent body.  相似文献   

Saturn: UBV photoelectric pinhole scans of the disk,II     

Michael J. Pricez  Otto G. Franz 《Icarus》1980,44(3):657-666

During the 1980 Saturn apparition, calibrated UBV pinhole scans of the disk were obtained with a photoelectric area-scanning photometer. Point spread function data were also taken. Equatorial and polar scans were used to investigate the structure of the Satur atmosphere. The observational geometry was optimum. Not only was Saturn at opposition, but the ring system was essentially edge on to both the Sun and Earth. Our analysis indicates that the atmosphere of Saturn can be represented by a finite clear H₂ layer overlaying a semi-infinite absorbent aerosol haze. The extent of the clear H₂ region appears to be latitude dependent. The H₂ column density varies systematically from ～15 km-am over the equatorial and polar regions to ～ 31 km-am at temperate latitudes. The hemispheres of the planet are similar. Our earlier conclusion, that the aerosol haze is strongly absorbent in the ultraviolet, is confirmed; its effective U-band single-scattering albedo is ～0.4. Latitudinal disk structure at visual wavelengths appears to be the result of local variations in the volume density of absorbent particles in the aerosol layer.  相似文献   

Stability Dependence of the Eddy-Accumulation Coefficients for Momentum and Scalars   总被引：1，自引：1，他引：0  

Edgar L. Andreas  Reginald J. Hill  James R. Gosz  Douglas I. Moore  William D. Otto  Achanta D. Sarma 《Boundary-Layer Meteorology》1998,86(3):409-420

From a set of turbulence data collected with a three-axis sonic anemometer/thermometer and described in a companion paper, we simulate the eddy-accumulation process for sensible heat and momentum fluxes. The resulting eddy-accumulation coefficient for momentum clearly depends on surface-layer stability; at neutral stability, its value is 0.63. On supplementing the scalar eddy-accumulation coefficients that we derive from our sensible heat flux data with values of sensible and latent heat flux coefficients reported by Businger and Oncley, we also find that scalar eddy-accumulation coefficients depend on stability, though more weakly than does the momentum coefficient. The coefficients for sensible and latent heat show no significant difference; we, thus, fit them with one function of stability whose value is 0.52 for neutral stratification.  相似文献   

Statistics of Surface-Layer Turbulence Over Terrain with Metre-Scale Heterogeneity   总被引：9，自引：8，他引：1  

Edgar L Andreas  Reginald J. Hill  James R. Gosz  Douglas I. Moore  William D. Otto  Achanta D. Sarma 《Boundary-Layer Meteorology》1998,86(3):379-408

Refuge has patchy vegetation in sandy soil. During midday and at night, the surface sources and sinks for heat and moisture may thus be different. Although the Sevilleta is broad and level, its metre-scale heterogeneity could therefore violate an assumption on which Monin-Obukhov similarity theory (MOST) relies. To test the applicability of MOST in such a setting, we measured the standard deviations of vertical (_w) and longitudinal velocity (_u), temperature (_t), and humidity (_q), the temperature-humidity covariance (¯tq), and the temperature skewness (S_t). Dividing the former five quantities by the appropriate flux scales (u_*, _*, and q_*) yielded the nondimensional statistics _w/u_*, _u/u_*, _t/|t_*|, _q/|q_*|, and ¯tq/t_*q_*. _w/u_*, _t/|t_*|, and S_t have magnitudes and variations with stability similar to those reported in the literature and, thus, seem to obey MOST. Though _u/u_* is often presumed not to obey MOST, our _u/u_* data also agree with MOST scaling arguments. While _q/|q_*| has the same dependence on stability as _t/|t_*|, its magnitude is 28% larger. When we ignore ¯tq/t_*q_* values measured during sunrise and sunset transitions – when MOST is not expected to apply – this statistic has essentially the same magnitude and stability dependence as (_t/t_*)². In a flow that truly obeys MOST, (_t/t_*)², (_q/q_*)², and ¯tq/t_*q_* should all have the same functional form. That (_q/q_*)² differs from the other two suggests that the Sevilleta has an interesting surface not compatible with MOST. The sources of humidity reflect the patchiness while, despite the patchiness, the sources of heat seem uniformly distributed.  相似文献   

Uranus: Narrow-waveband disk profiles in the spectral region 6000 to 8500 Angstroms     

Michael J. Price  Otto G. Franz 《Icarus》1979,38(2):267-287

New narrow-band (100 Å) photoelectric slit scan photometry of Uranus has been obtained in the spectral region 6000 to 8500 Å. Coarse radial intensity profiles in seven wavebands are presented. Measurements of the point spread function have been used to partially remove the effects of atmospheric seeing. Restoration of the Uranus image, with a spatial resolution limit ～0″.5 arc, has been achieved by means of analytical Fourier-Bessel inversion. Results of the investigation confirm earlier studies of limb brightening on the Uranus disk. But not all strong CH₄ absorption bands are found to exhibit limb brightening. Specifically, the CH₄ bands at 8000 and 8500 Å show pronounced apparent limb darkening. Polar brightening may be responsible for the phenomenon. If so, an aerosol haze with a local optical thickness ～0.5 or greater would be required. Visibility of the dense cloud layer located deep in the atmosphere might also cause apparent limb darkening. If so, the maximum permitted [CH₄/H₂] mixing ratio in the visible atmosphere would correspond to ～3 times the solar value.  相似文献   

UBV photometry of Triton     

Otto G. Franz 《Icarus》1981,45(3):602-606

UBV measurements of Triton relative to Neptune were obtained with an area-scanning photometer on 11 nights during the 1977 apparition. Observed orbital brightness variation shows that Triton is locked in synchronous rotation around Neptune. Its leading side, seen at greatest western elongation, is found to be 0.06 mag brighter than its trailing hemisphere.  相似文献