Hydrological tracing practice on underground contaminations   总被引：1，自引：0，他引：1  

W. A. Käss 《Environmental Geology》1994,23(1):23-29

The hydrological tracing technique is an important tool for the risk assessment of problem sites, the so-called Altlasten (old underground contaminations). The penetration of leachate through the unsaturated zone, the transport velocity, the migration pathways, as well as the dispersion in the aquifer can be determined by tracing experiments. A wide range of tracers offer sufficient possibilities to get the necessary hydrogeologic parameters for any kind of Altlasten. This is shown by some examples.An English version of Hydrologische Markierungstechnik bei der Altlastensanierung in: Die Geowissenschaften, Weinheim 10(2): 199–205  相似文献   

Contaminant exposure and effects in Baltic ringed and grey seals as assessed by biomarkers   总被引：3，自引：0，他引：3  

Nyman M  Bergknut M  Fant ML  Raunio H  Jestoi M  Bengs C  Murk A  Koistinen J  Bäckman C  Pelkonen O  Tysklind M  Hirvi T  Helle E 《Marine environmental research》2003,55(1):73-99

The Baltic Sea ecosystem has suffered from a heavy pollutant load for more than three decades. Persistent organic pollutants (POPs) and heavy metals have been of most concern due to their persistence and toxic properties. Ringed seals (Phoca hispida baltica) and grey seals (Halichoerus grypus) living in the Baltic Sea have been suffering from pathological impairments, including reproductive disturbances, which have resulted in a depressed reproductive capacity. We investigated several biochemical parameters as potential biomarkers for exposure to and effects of the contaminant load in the Baltic seals. Seals from less polluted areas were used as reference material in terms of the pollution load. In both Baltic seal populations, the levels of some biochemical parameters diverged from those in the reference seals, and some of these showed a clear correlation with the individual contaminant load. Of the potential bioindicators, we propose cytochrome P4501A activity and vitamin E levels, in blubber or plasma, as exposure biomarkers for polychlorinated biphenyls (PCBs) and dichlorodiphenyltrichloroethane (DDT) in both species. The arylhydrocarbon receptor-mediated chemical-activated luciferase gene expression (CALUX) response reflects the whole PCB and DDT burden in ringed seals. Retinyl palmitate (vitamin A) levels showed a negative correlation with the individual POP load, and is proposed as potential effect biomarkers for the depletion of the vitamin A stores. As the nutritional levels of both vitamin A and E have an impact on the vitamin levels in the seals, more information on the dietary vitamin levels is needed before any conclusions can be drawn. As the relationship between biochemical parameters and contaminants varied between the two species, species-specific characteristics has to be considered when monitoring the health status and possible toxic effects of the contaminant load in ringed and grey seals.  相似文献   

Response of Coastal Groundwater Table to Offshore Storms   总被引：1，自引：0，他引：1  

李凌  N.Cartwright  P.Nielsen  D.Lockington 《中国海洋工程》2004,18(3):423-431

Large groundwater table fluctuations were observed in a coastal aquifer during an offshore storm. The storm induced significant changes of the mean shoreline elevation, characterized by a pulse-like oscillation. This pulse propagated in the aquifer, resulting in the water table fluctuations. A general analytical solution is derived to quantify this new mechanism of water table fluctuation. The solution is applied to field observations and is found to be able to predict reasonably well the observed storm-induced water table fluctuations. Based on the analytical solution, the damping characteristics and phase shift of the oscillation as it propagates inland are examined.  相似文献   

Zones of impact metamorphism in the crystalline rocks of the Nördlinger Ries crater     

Dieter Stöffler 《Contributions to Mineralogy and Petrology》1966,12(1):15-24

Fragments of crystalline basement rocks in suevite, a tuff-like breccia found in the area of the Nördlinger Ries crater, display a continuous gradation of metamorphism. This is interpreted as an effect of the shock waves caused by meteoritic impact, the degree of metamorphism reflecting a radial gradient of pressure and temperature diminishing outward from the point of impact. This phenomenon gives further support to the theory that Ries crater is of meteoritic origin and that suevite is not volcanic in nature. A classification of varying impact facies in crystalline rocks is proposed. It is hoped that the system proposed may prove valid for impact structures in other areas.  相似文献   

Über das Flimmern und Schweben des Zielbildes     

Dr. T. J. Kukkamäki 《Pure and Applied Geophysics》1950,18(1):120-127

Zusammenfassung In zwei Beobachtungsserien von 24 Stunden ist jede zweite Stunde die Schwankung des Zielbildes beobachtet und gleichzeitig die Temperaturdifferenz zwischen den Höhen 0.5 und 2.5 m gemessen worden. Aus diesen Beobachtungen gehen folgende Resultate hervor. Kurz nach Sonnenaufgang ist das Zielbild unbeweglich. Bald beginnt es zu flimmern, zuerst schwach und langsam (einmal in der Sek.) später stärker und schneller (5 mal in der Sek.). Das Flimmern erreicht sein Maximum etwas nach Mittag, vermindert sich dann und wird Null kurz vor Sonnenuntergang. Von hier an beginnt das Zielbild sehr langsam (in Perioden von Minuten) zu schweben. Der Betrag des Flimmerns ist proportional der 1.68-Potenz der Zielweite. Sie hängt von dem Temperaturgradienten ab, und z. B. bei der Zielweite 75 m beträgtF ₇₅=0.66–1.42 mm, wo die Temperaturdifferenz zwischen den Höhen 0.5 und 2.5 m bezeichnet. Der Betrag des Schwebens ist proportional der 2.05-Potenz der Zielweite. Sie hängt von dem Temperaturgradienten ab, und z. B. bei der Zielweite 125 m beträgtS ₁₂₅=1.3+4.02 mm, wo die obenangegebene Bedeutung hat. Zwischen dem ZielungsfehlerZ und dem FlimmernF besteht die BeziehungZ=0.11++0.029F mm. Das Schweben wirkt sehr stark auf die Zielungsgenauigkeit ein, obgleich beim Vorkommen des Schwebens das Zielbild nach dem Augenmass unbeweglich erscheint.

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Summary The oscillation of the sight point picture in telescope and simultaneously the difference of the air temperatures between the hights of 0.5 and 2.5 meters have been observed every two hours through two clear days and nights. Hereby the following results have been obtained. Short after the sunrise the sight point picture is quite immovable. Soon after it beginns to vibrate, at first slightly and slowly (one time in second) and then more violently and quickly (five times in second). The vibration attains its maximum short after the noon, then it decreases and becomes zero not long before the sunset. From now till the sunrise the sight point picture is swaying very slowly (in periods of several minutes). The vibration is proportional to the 1.68-power of the sight length. It correlates the vertical temperature gradient, and the vibration is e. g. for the sight of 75 m:F ₇₅=0.66–1.42 mm, where means the temperature increase from 0.5 to 2.5 m (here negative). The swaying is proportional to the 2.05-power of the sight length. It correlates the gradient, and the swaying is e. g. for the sight of 125 m:S ₁₂₅=1.3+4.02 mm, where has the same meaning as above. Between the sight errorZ and the vibrationF a relation:Z=0.11+0.029F mm is to be seen. Thus the accuracy of the sighting is not very sensitive to the vibration.

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Exploring the usability of PPGIS among older adults: challenges and opportunities     

Sarah Gottwald  Tiina E. Laatikainen  Marketta Kyttä 《International journal of geographical information science》2016,30(12):2321-2338

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Development of a model-based high-resolution extreme surface wind climatology for Switzerland   总被引：1，自引：0，他引：1  

Stéphane Goyette 《Natural Hazards》2008,44(3):329-339

An innovative methodology aimed at establishing a numerical model-based high-resolution climatology of extreme winds over Switzerland is described, that makes use of the Canadian Regional Climate Model where a new windgust parameterization has been implemented. Self-nesting procedures allow windstorms to be studied at resolution as high as 2-km. The analysis of ten major windstorms concludes that the average spatial pattern and magnitude of the simulated windspeeds are well captured, and the areas that experienced extreme winds correspond well with observations and to the location where forest damage was reported following the last two of these storms. This climatology would eventually serve to form risk assessment maps based on the exceedance of windspeed thresholds. There is, however, a need for further investigations to encompass the full range of potential extreme wind cases. The ultimate goal of this methodology is to assess the change in the behaviour of extreme winds for a climate forced by enhanced greenhouse gas concentrations, and the impact of future windstorms over the Alpine region at high resolution.  相似文献   

The behaviour of consolidated volcanic tuffs: weathering mechanisms under simulated laboratory conditions   总被引：1，自引：0，他引：1  

H. Stück  L. Z. Forgó  J. Rüdrich  S. Siegesmund  Á. Török 《Environmental Geology》2008,56(3-4):699-713

Five volcanic tuffs ranging from dacitic tuffs of Hungary to rhyolite, phonolite and basaltic tuffs of Germany were consolidated under laboratory conditions. Prior to consolidation an anti-hygro, a hydrous consolidant, which reduces the swelling ability of clay minerals, was applied. The three consolidants, a silicic acid ester (SAE), an elastic silicic acid ester (eSAE) and an acrylate resin (PMMA) were applied on test specimens under vacuum. Petrographic characterisation (polarizing microscopy, XRD, SEM) provided data for fabric analyses and the mineral composition of the tuffs. Changes in fabric, effective porosity, density, tensile strength, ultrasonic wave velocity were evaluated after the treatment. Weathering simulation tests such as hygric dilatation and thermal dilatation aimed to prove the effectiveness of consolidation and the durability of consolidated tuff samples. More than 500 samples were analysed. The tests showed that SAE caused the highest increase in indirect tensile strength. The water absorption and the pore size distribution of the tuffs were modified by consolidation. The PMMA reduced the water absorption the most, whereas SAE modified it the least. All the tested consolidants increased the thermal dilatation of the tuffs. The changes in hygric dilatation were not uniform: for most tuffs SAE increased and PMMA decreased the hygric dilatation, although the clay-rich Habichtswald tuff showed the opposite trend. The changes in hygric and thermal behaviour of consolidated tuff require special care when specific consolidants are chosen. These products modify the physical properties of consolidated tuffs and change the behaviour of weathering.  相似文献   

Mesozoic to Quaternary continental margin dynamics in South-Central Chile (36–42°S): the apatite and zircon fission track perspective     

Johannes Glodny  Kirsten Gräfe  Helmut Echtler  Matthias Rosenau 《International Journal of Earth Sciences》2008,97(6):1271-1291

Zircon and apatite fission track data provide constraints on the exhumation history, fault activity, and thermal evolution of the South-Central Chilean active continental margin (36°S–42°S), which we use to assess the tectonic and geomorphic response of the margin to the Andean subduction regime. Several domains with different exhumation histories are identified. The Coastal Cordillera is characterized by uniform and coherent exhumation between Late Triassic (～200 Ma) and late Miocene times, with surprisingly slow average rates of 0.03–0.04 mm/a. Thermal anomalies, related to Late Cretaceous and early Miocene magmatism, have regionally modified fission track age patterns. The Upper Cretaceous thermal overprint is of previously unrecognized significance and extent in the Coastal Cordillera south of 39°S. With the exception of a local but distinct Pliocene to Recent exhumation period in the high-relief Cordillera Nahuelbuta segment between 37°S and 38°S, Cenozoic overall exhumation in the Coastal Cordillera was very slow. The sedimentary record shows that uplift and subsidence here was episodic, with low amplitudes and durations. This rules out large-scale, long-term, Cenozoic accretion, trench-parallel tilting, and tectonic erosion processes in the forearc. The Main Andean Cordillera shows markedly greater long-term exhumation rates than the Coastal Cordillera and, at ～39°S, a steep exhumation gradient. To the south, long-term average Pliocene to Recent exhumation rates of ～1 to ～2 mm/a in the Liquiñe area (39°45′S) are almost an order of magnitude more rapid than average Paleogene to Recent exhumation near Lonquimay (38°30′S) and farther north. While no imprint of the intra-arc Liquiñe-Ofqui Fault Zone on the exhumation pattern is evident, long-term exhumation rates decrease from the crest of the Andes toward the western foothills. Exhumation gradients correlate with climatic gradients, suggesting a causal link to the variable intensity of late Miocene to Pleistocene glacial erosion.  相似文献   

Comment on: “Corrections to the Mathematical Formulation of a Backwards Lagrangian Particle Dispersion Model” by Gibson and Sailor (2012: Boundary-Layer Meteorology 145, 399–406)     

Stefan Stöckl  Mathias W. Rotach  Natascha Kljun 《Boundary-Layer Meteorology》2018,166(1):153-160

We discuss the results of Gibson and Sailor (Boundary-Layer Meteorol 145:399–406, 2012) who suggest several corrections to the mathematical formulation of the Lagrangian particle dispersion model of Rotach et al. (Q J R Meteorol Soc 122:367–389, 1996). While most of the suggested corrections had already been implemented in the 1990s, one suggested correction raises a valid point, but results in a violation of the well-mixed criterion. Here we improve their idea and test the impact on model results using a well-mixed test and a comparison with wind-tunnel experimental data. The new approach results in similar dispersion patterns as the original approach, while the approach suggested by Gibson and Sailor leads to erroneously reduced concentrations near the ground in convective and especially forced convective conditions.  相似文献