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31.
Remote sensing of water colour and its application to the mapping of pigments, suspended matter and other substances by means of airborne and spaceborne sensors is discussed. After an introduction to the physical process involved, the methods for a quantitative interpretation especially of CZCS data are indicated. Applications towards the monitoring of coastal pollution, of algae blooms and of dynamic processes are shown by means of selected examples. Multispectral scanner and imaging spectrometer technologies are discussed with special reference to NASA's Earth Observation System and ESA's Earth Observation Programme. 相似文献
32.
A profundal sediment core from Höllerer See frozen in situ was studied by means of diatom, microstratigraphical tape peel and pollen analyses. Varved sequences reflect eutrophication during mediaeval settlement and according to varve counts a recent eutrophic phase since the 1970's. Mesotrophication in-between coincides with regrowth of forests near the lake. 相似文献
33.
Dr. Roland Salchow 《Ocean Dynamics》1991,44(5-6):363-382
34.
The molecules constituting the first hydrate layers on montmorillonite crystal platelets appear to be characterized by preferred orientation and, depending on the exchangeable cation, by an ice-like configuration. Such organized interlamellar water is concluded to contribute to the high swelling pressure and shear resistance, as well as to the very low hydraulic conductivity at high clay bulk densities. At low densities the parallel arrangement of the lamellae alters to edge-to-face associations and the fraction of free water increases. However, even at very low densities the homogeneity of the clay gel still offers very tortuous passages to flowing water, which is manifested by a very low hydraulic conductivity. 相似文献
35.
Roland Pusch 《Engineering Geology》1984,20(4):301-310
The heterogeneous character of rock suggests the use of statistical mechanics for the formulation of models of plasticity and creep. A stochastic creep model which allows for large variations in strength and size of the involved rock mass is outlined. The model, which is analogous to a previously developed concept for clastic materials, is shown to account rather well for typical creep behaviour of rock at moderate stresses and temperatures. Thus, it yields the often observed linear relation between the creep strain and the logarithm of time. 相似文献
36.
Information about topography, the shape of the geoid, seismicity, Neogene deformation and volcanism in the region of Altiplano-Puna of western South America is used to analyse the state of stress across the convergent plate margin in terms of the effects of topography and simple models of its compensation. An average elevation near 4 km is consistent with compensation by a yet unresolved combination of crustal root and hot uppermost mantle producing a geoid high of 22–27 meters, average horizontal compressive stress (in excess of a reference sea level lithostatic value) of 390 bars in a 150 km thick lithosphere, and an average shear stress of 170 bars along a 30° dipping interplate boundary. The basis for these estimates is evidence for a neutral to extensional stress regime within the high plateau contrasted with a compressional regime on the eastern slopes and along the interplate boundary itself. Comparison with other plateaus in a convergent plate tectonic setting suggests an evolutionary sequence from compressional to extensional tectonics as elevation of the plateau increases. 相似文献
37.
E. Mahieu C. P. Rinsland R. Zander P. Demoulin L. Delbouille G. Roland 《Journal of Atmospheric Chemistry》1995,20(3):299-310
A set of high-resolution IR solar spectra recorded at the International Scientific Station of the Jungfraujoch, Switzerland, from 84/06 to 93/06, and at the National Solar Observatory McMath-Pierce solar telescope facility on Kitt Peak, Arizona, U.S.A. from 78/05 to 92/07 have been analyzed to determine the vertical column abundances of hydrogen cyanide, HCN, above the two stations. The analysis was based on least-squares curve fitting of calculated spectra to the observations encompassing the P4 and the P8 lines of HCN respectively located at 3299.5273 and 3287.2483 cm–1. The results obtained for the two stations indicate that no significant long-term trend affects either of the two databases; however, this analysis reveals variable increases during springtime of up to a factor of 2 in the HCN total column above the Jungfraujoch and even up to 3 above Kitt Peak. The calculated mean vertical column abundances, excluding the spring observations, are equal to (2.55±0.30)×1015 molec./cm2 (S.D.) and (2.75±0.30)×1015 molec./cm2 respectively above the Jungfraujoch and the Kitt Peak observatories. Based on a realistic volume mixing ratio profile, these columns translate into mean volume mixing ratios equal to 190×10–12 ppv at the respective altitudes of the stations. 相似文献
38.
Sybille Wunsam Roland Schmidt Rolf Klee 《Aquatic Sciences - Research Across Boundaries》1995,57(4):360-386
Surface sediment diatom assemblages for 86 Alpine lakes were analysed focusing on the dominant genusCyclotella and corresponding environmental data. The range of morphological variability of theCyclotella bodanica/radiosa, C. distinguenda, C. ocellata, C. comensis andC. stelligera complexes was documented. Significance tests included in the canonical correspondence analysis (CCA) indicated that total phosphorus, conductivity and surface water temperature were significantly correlated withCyclotella taxa assemblage distribution. Numerical species optima and tolerances were calculated in respect to these significant variables using weighted averaging (WA) regression and calibration. CCA and WA were able to provide information about the environmental preferences of the various morphotypes observed. 相似文献
39.
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