Carbonyls and nonmethane hydrocarbons at rural European sites from the mediterranean to the arctic     

Sverre Solberg  Christian Dye  Norbert Schmidbauer  Alex Herzog  Robert Gehrig 《Journal of Atmospheric Chemistry》1996,25(1):33-66

Results of regular measurements during 1992–1995 of hydrocarbons and carbonyl compounds for a number of rural European monitoring sites are presented. The measurements are part of the EMEP programme for VOC measurements in Europe. In addition, several years of regular measurements are included from the Norwegian stations Birkenes at the south coast, and Zeppelin Mountain on Spitsbergen in the Arctic. The sampling frequency has been about twice per week throughout the years, implying that a substantial amount of measurement data are available. Almost all the chemical analyses have been performed by one laboratory, the EMEP Chemical Co-ordinating Centre located at NILU, which avoids problems of intercomparison and intercalibration among different laboratories. For the measured concentrations both seasonal and geographical variations are shown and discussed. The diurnal cycles of the hydrocarbon concentrations were studied in detail at one site, where the grab samples by EMEP where compared with a parallel continuous sampler, operated by EMPA, Switzerland. Hydrocarbons linked to natural gas and fuel evaporation become well mixed into the Arctic in the winter, whereas combustion products show a latitudinal gradient. The sum of oxygenated species constitutes about 5–15% of the sum of C₂–C₅ hydrocarbons in winter. In summer they are almost equal in magnitude, consistent with an increasing oxidation of hydrocarbons.  相似文献   

Sr and Ar isotope studies of detrital smectites from the Atlantic Ocean (D.S.D.P., Legs 43, 48 and 50)     

Norbert Clauer  Patrick Giblin  Jacques Lucas 《Chemical Geology》1984,46(2):141-151

Mineralogical, morphological and isotopic (RbSr and KAr) determinations were made on some detrital smectites of Palaeocene and Cenomanian ages from D.S.D.P. drillings in the Atlantic Ocean. These minerals are not inert in their depositional environment; authigenic laths grow on detrital sheets with sharp borders. This authigenesis could occur slightly after deposition in a closed system, for some of these smectites. It has been tentatively quantified by the RbSr and KAr isotopic methods, which seem also well suited to evaluate the chemical extent of this authigenesis. At least, no preferential loss of ⁴⁰Ar vs. ⁸⁷Sr could be detected in the minerals, even in those which are smaller than 0.2 μm.  相似文献   

Self-diffusion studies of pore fluids in unconsolidated sediments by PFG NMR     

Corina Vogt  Petrik Galvosas  Norbert Klitzsch  Frank Stallmach   《Journal of Applied Geophysics》2002,50(4)

The self-diffusion of water and hexadecane in medium and coarse sands from glacial sand deposits in central Germany were investigated by pulsed field gradient nuclear magnetic resonance (PFG NMR). Due to the restriction of the diffusion path at the pore/grain interface, the measured apparent self-diffusion coefficients (D(Δ)) in the pore space depend on the observation time (Δ) in the PFG NMR experiment. Although the bulk self-diffusion coefficients of water and hexadecane differ by about one order of magnitude, the apparent self-diffusion coefficients in the pore space obey the same characteristic time-behaviour, which depends only on geometrical properties of the pore system. Using the “short-time diffusion” model, surface-to-volume (S/V) ratios and inherent self-diffusion coefficients (D₀) of the pore fluids were extracted from these diffusion measurements. The S/V ratios obtained are independent of the pore fluid used and agree with known geometrical properties of the sand grains. Moreover, the D₀ values are consistent with the corresponding bulk self-diffusion coefficients measured separately. In contrast to these results of PFG NMR, simultaneous investigations of longitudinal (T₁) nuclear magnetic relaxation reveal that the relaxation time of the pore fluid is a less suitable parameter for a quantitative estimation of geometrical properties of the pore/grain interface in these unconsolidated sediments since it depends on chemical properties of the fluid/grain interface.  相似文献   

Further rock magnetic and chronostratigraphic results on reversal excursions during the last 50 ka as derived from northern high latitudes and discrepancies in precise AMS ¹⁴C dating     

Norbert R. Nowaczyk  Martin Antonow  Jochen Knies  Robert F. Spielhagen 《Geophysical Journal International》2003,155(3):1065-1080

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An update on automatic 3D building reconstruction   总被引：3，自引：0，他引：3  

Norbert Haala  Martin Kada   《ISPRS Journal of Photogrammetry and Remote Sensing》2010,65(6):570-580

The development of tools for the generation of 3D city models started almost two decades ago. From the beginning, fully automatic reconstruction systems were envisioned to fulfil the need for efficient data collection. However, research on automatic city modelling is still a very active area. The paper will review a number of current approaches in order to comprehensively elaborate the state of the art of reconstruction methods and their respective principles. Originally, automatic city modelling only aimed at polyhedral building objects, which mainly reflects the respective roof shapes and building footprints. For this purpose, airborne images or laser scans are used. In addition to these developments, the paper will also review current approaches for the generation of more detailed facade geometries from terrestrial data collection.  相似文献   

Phosphorus input by upwelling in the eastern Gotland Basin (Baltic Sea) in summer and its effects on filamentous cyanobacteria     

Monika Nausch  Günther Nausch  Hans Ulrich Lass  Volker Mohrholz  Klaus Nagel  Herbert Siegel  Norbert Wasmund   《Estuarine, Coastal and Shelf Science》2009,83(4):434-442

In July 2007, phosphorus input by an upwelling event along the east coast of Gotland Island and the response of filamentous cyanobacteria were studied to determine whether introduced phosphorus can intensify cyanobacterial bloom formation in the eastern Gotland Basin. Surface temperature, nutrient concentrations, phytoplankton biomass and its stoichiometry, as well as phosphate uptake rates were determined in two transects between the coasts of Gotland and Latvia and in a short grid offshore of Gotland. In the upwelling area, surface temperatures of 11–12 °C and average dissolved inorganic phosphorus (DIP) concentrations of 0.26 μM were measured. Outside the upwelling, surface temperatures were higher (15.5–16.6 °C) and DIP supplies in the upper 10 m layer were exhausted. Nitrite and nitrate concentrations (0.01–0.22 μM) were very low within and outside the upwelling region. Abundances of filamentous cyanobacteria were highly reduced in the upwelling area, accounting for only 1.4–6.0% of the total phytoplankton biomass, in contrast to 18–20% outside the upwelling. The C:P ratio of filamentous cyanobacteria varied between 32.8 and 310 in the upwelling region, most likely due to the introduction of phosphorus-depleted organisms into the upwelling water. These organisms accumulate DIP in upwelling water and have lower C:P ratios as long as they remain in DIP-rich water. Thus, diazotrophic cyanobacteria benefit from phosphorus input directly in the upwelling region. Outside the upwelling region, the C:P ratios of filamentous cyanobacteria varied widely, between 240 and 463, whereas those of particulate material in the water ranged only between 96 and 224. To reduce their C:P ratio from 300 to 35, cyanobacteria in the upwelling region had to take up 0.05 mmol m⁻³ DIP, which is about 20% of the available DIP. Thus, a larger biomass of filamentous cyanobacteria may be able to benefit from a given DIP input. As determined from the DIP uptake rates measured in upwelling cells, the time needed to reduce the C:P ratio from 300 to 35 was too long to explain the huge bloom formations that typically occur in summer. However, phosphorus uptake rates increased significantly with increasing C:P ratios, allowing phosphorus accumulation within 4–5 days, a span of time suitable for bloom formation in July and August.  相似文献   

Regime shifts in the marine environment: the scientific basis and political context   总被引：1，自引：0，他引：1  

Kraberg AC  Wasmund N  Vanaverbeke J  Schiedek D  Wiltshire KH  Mieszkowska N 《Marine pollution bulletin》2011,62(1):7-20

Regime shifts in the marine environment have recently received much attention. To date, however, few large-scale meta-analyses have been carried out due to insufficient data coverage and integration between sustained observational datasets because of diverse methodologies used in data collection, recording and archival. Here we review the available data on regime shifts globally, followed by a review of current and planned policies with relevance to regime shifts.We then focus on the North and Baltic Seas, providing examples of existing efforts for data integration in the MarBEF Network of Excellence. Existing gaps in data coverage are identified, and the added value from meta-analyses of multiple datasets demonstrated using examples from the MarBEF integrated data project LargeNet. We discuss whether these efforts are addressing current policy needs and close with recommendations for future integrated data networks to increase our ability to understand, identify and predict recent and future regime shifts.  相似文献   

New findings on the tectono-metamorphic history of the western Rhenish Massif (Germany) by K–Ar dating of metasedimentary illite     

Rolf Nierhoff  Norbert Clauer  Gerhard Spaeth 《Journal of Geodynamics》2011

Metapelites, clay-rich sandstones and volcanics from Cambrian, Ordovician and Lower Devonian strata of the western Rhenish Massif underwent a complex regional Variscan tectono-thermal evolution, as shown by mineralogical and K–Ar isotopic analyses of the illite to mica components from three NW-SE transects. The metamorphic degree extended from an anchimetamorphic to an epimetamorphic intensity during two major episodes of illite crystallization at 328 ± 6 and 282 ± 12 Ma. A further late orogenic or post-orogenic extensional activity could also be detected, but not precisely, around 270 Ma, probably recorded by the precipitation of illite in new or reactivated extensional faults with upward moving heat flows.  相似文献   

Reply to the comment of Mitchell et al. (2010) on “Formation of Thetis Deep metal-rich sediments in the absence of brines,Red Sea” by Pierret et al. (2010)     

Marie-Claire Pierret  Norbert Clauer 《Journal of Geochemical Exploration》2011

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Expected damage from displacement of slow-moving slides   总被引：10，自引：7，他引：3  

Mohamed Farouk Mansour  Norbert R. Morgenstern  C. Derek Martin 《Landslides》2011,8(1):117-131

Facilities such as buildings, highways, railways, bridges, dams and pipelines often are built on natural slopes where the risk of landslides is not low. The vulnerability of these facilities to slow-moving slides has sometimes been underestimated, although the velocity of some classes of slow slides is uncontrollable. More than 50 cases of slow slides were compiled from the literature for this study. Some statistics about the movement trigger(s), the methods used to measure displacement, the material forming the rupture surface and the type of the vulnerable facilities are presented. It is shown that the expected degree of damage to urban settlements, highways, bridges and dams can be related to the slide velocity or accumulating displacement. Buildings and residential houses may tolerate higher slide velocities and total displacements than other facilities before experiencing serious damage. Movements as low as 100 mm may severely damage bridges, but such low rates may cause only moderate damage to urban communities. The relationship between movement and the expected extent of damage should be useful to geotechnical engineers who deal with different classes of slow slides and will help in the choice of appropriate mitigation measures based on preliminary estimates of movement rates.  相似文献