Total vertical column abundances of carbonyl fluoride (COF2) have been derived from observations made at the International Scientific Station of the Jungfraujoch (ISSJ; altitude 3.58 km, latitude 46.5°N, longitude 8.0°E), Switzerland. A systematic analysis of two microwindows containing lines of the 1 band was performed, based on a large set of high resolution infrared solar absorption spectra recorded with Fourier transform spectrometers, from 1985 to 1995. Examination of the whole available database indicates a significant increase of the burden of COF2 during the 1988–1995 period. The average exponential rate and the average linear rate referenced to 1992, calculated from daily mean measurements, are both equal to (4.0 ± 0.5)% yr-1 (one error). The results are also evaluated and discussed within the context of seasonal variability and correlation between carbonyl fluoride and hydrogen fluoride (HF) columns above the ISSJ. 相似文献
The conventionally applied method for visualizing the structure of a rock mass is limited to plotting the orientation of individual discontinuities by using the Schmidt stereographic net. Their spacing is not illustrated and other structural features, such as undulation and twisting, cannot be interpreted from such sterographic views. A new mode of visual presentation of rock structural features of one or several different types in rock volumes of any size that makes all this possible is proposed in the present report. The primary purpose is to quantify, for all elements of a rock mass where the structure has been evaluated by borehole investigations or mapping in the course of underground excavation, the orientation and average spacing of defined discontinuities like hydraulically and mechanically active fractures. These local structural patterns, which are plotted on three of the six faces of cubical boxes with defined edge length and with one edge oriented N−S can be combined by applying the mathematical tool for connecting faces with which certain visualization codes like Alias Sketch are equipped. This combines different local rock structures to form regional patterns that can reveal undulation and twisting and important variations in spacing of major discrete discontinuities. Visualization can be given in true perspective or orthographic form and larger discontinuities that have been identified in the field, such as fracture zones, can be introduced in the model for correlation with smaller features. Furthermore, the stress situation at all sites where rock stress measurements have been made can be visualized in the model in the form of principal planes. The proposed models can be visualized from any “camera angle” and also shown in Quick Time VR form, i.e. as being slowly rotated around any predetermined axis. This facilitates definition and selection of the rock structure, local or regional, for numerical calculations. 相似文献
Goal and Scope. The UNECE heavy metals in Mosses Surveys provide data on the accumulation of metals in naturally growing mosses throughout Europe. Using Germany as an example, this article concentrates on the elaboration and application of methods of data analysis that are necessary for a comprehensive interpretation of spatial and temporal trends in metal accumulation.Methods and Results. The sampling of mosses, and the chemical analysis of Cr, Cu, Fe, Ni, Pb, Ti, V and Zn in 1990, 1995 and 2000 are summarized briefly. The variogram analyses detect distinct autocorrelation structures in the sample data which may consequently be estimated for all sites in Germany without monitoring metal accumulation by means of ordinary kriging. A procedure for the geostatistical detection of spatial outliers was developed and applied and, after the elimination of the spatial outliers, several measurements were seen to indicate an adequate quality of the geostatistical estimations. The cluster analyses of the z-transformed estimation data result in a nominal multi-element index that indicates regional metal accumulation types over time. Percentile statistics serve for computation of an ordinal, scaled, multi-element accumulation index which is spatially differentiated over time in terms of multivariate, statistically defined ecoregions. The integrative statistical analysis reveals, from 1990 to 2000, that the metal accumulation declines up to 80% in some of the ecoregions. Hot spots of metal accumulation are mapped and interpreted by means of metadata analysis.Conclusions. Dot maps depict the spatial structure of the metal accumulation without spatial bias. This information, detailed with respect to metal species and space, should be generalized for better supporting the interpretation. The combination of geostatistical analysis and estimation, percentile and multivariate statistics is suitable for the calculation of indices that serve for a comprehensive mapping of metal accumulation in the ecoregions over time, for quantifying the bias of the surface estimation, and for mapping spatial outliers and hot spots of metal accumulation. 相似文献
Balloon-borne aerosol measurements were performed with an optical particle counter between 1994 and 2000 at Ny-Ålesund (79°N), Svarbard. Throughout the observation period, continuous decay was found in the concentrations of particles with 0.4–0.6 μm in radius in the Arctic stratosphere, suggesting that Pinatubo aerosols remained even at the end of the 1990s. The decay rate was clearly higher for larger particle sizes, and higher at higher altitude (e-folding time of 970–526 days), suggesting a gravitational sedimentation effect. For smaller particles with R<0.4 μm, slight increases in concentration with time were found, which agreed with the measurements at mid-latitude. The sulfate mass mixing ratio in the Arctic stratosphere before 1998 showed values higher than those at middle latitude, while values were almost the same in both regions after 1998. A possible explanation of the latitudinal difference is a time lag (of 0.5–1 year) in the arrival of Pinatubo aerosols in the Arctic. 相似文献
Zusammenfassung Am Vogelsberg wurde erprobt, inwieweit rheologische Gefüge-Untersuchungen den Bau von Vulkankomplexen aufzuhellen vermögen. Lineare Merkmale (Blasen, Rücken, Rinnen, Kontraktionsklüfte, Fluidaltextur) und vektorielle (Blasenröhren, Blasenzüge, Faltenvergenz) wurden an vielen Punkten in größerer Zahl gemessen und statistisch verarbeitet. Es ergab sich, daß alle Merkmale für örtliche Störungen stark anfällig sind. Trotzdem hat die Methode, kritisch verwandt, ihren Wert.Der Vogelsberg hat seinen gegenwärtigen rundlichen Umriß wohl einer späteren leichten Caldera-Senkung zu verdanken.
In the case of the Vogelsberg the question was discussed, if the observation of flow fabrics in lava may offer advantages for the understanding of volcano complexes. Linear characteristics (vesicles, ridges, channels, contraction joints, fluidal texture) and vectorial ones (spiracles, pipe vesicles, vergent folds) were measured and statistically evaluated. All flow characteristics are highly susceptible to local conditions. But nevertheless, rheological methods are, critically applied, valuable.The present circular outline of the Vogelsberg probably results from a slight postvolcanic caldera subsidence.
Résumé A propos du Vogelsberg on a abordé le problème, si la détermination des traces d'écoulement dans les laves peût éclaircir la genèse des complexes volcaniques. Des caractéristiques linéaires (amygdales, arêtes, sillons, fissures de contraction, texture fluidale) et vectorielles (spiracules, tubes à vésicules, plis vergents) furent mesurés et calculés selon les règles statistiques. Il en résulte, que toutes les traces rhéologiques dépendent sensiblement des conditions locales d'écoulement. Mais malgré cela, la méthode, employée avec critique, est précieuse. Le Vogelsberg a reçu son présent contour circulaire par un léger effondrement de caldéra.
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Bei den Begehungen und Messungen waren dankenswerter Weise eine Reihe Bonner Geologie-Studenten behilflich, vor allem Dr.Clausen und Dr.Weber. Herrn Dr. W.Schenk-Hungen und Herrn Dr.Matthes-Wiesbaden danke ich für Erörterungen und Auskünfte. 相似文献
The article deals with a quick clay which was originally deposited in sea water. By leaching in situ the salt content has been reduced to a very small value.
By using a special technique for step-wise replacement of pore water with acrylate plastic, 500Aothick sections were cut with a precision microtome. The sections were photographed in an electron microscope and the micrographs obtained could be used for a study of the clay microstructure.
The microstructure is characterized by a linkage of groups or chains of small particles in and between denser flocs or aggregates or between bigger particles. There is no preferential orientation either of small or of bigger particles.
A preliminary study of the quick clay and of unleached parts of the same clay stratum has not revealed any microstructural differences.
The extreme thinness of the clay sections means that the micrographs reveal pores larger than about 500Ao. Thus the micrographs give a fairly complete picture of the size and shape variation of the micropores in the clay. By measuring the maximum dimension of all pores which could be identified and by using suitable methods for statistical condensation, representative values of mean pore size and two-dimensional “porosity” were obtained. These characteristics are discussed in relation to the permeability and strength properties of the quick clay and of some fresh- and brackish-water deposited clays which have been investigated previously.
Finally, on the basis of the micrographs a hypothesis is made concerning the rate of settlement. 相似文献