Le Dosage Du Carbone Particulaire Dans L'Eau De Mer Et Son Application Dans Le Golfe Du Lion     

Szekielda  Karl-Heinz 《ICES Journal of Marine Science》1969,32(3):318-343

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Upwelling Studies With Satellites     

Szekielda  Karl-Heinz 《ICES Journal of Marine Science》1972,34(3):379-388

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Pattern recognition of suspended material     

Szekielda  Karl-Heinz; Duvall  James T. 《ICES Journal of Marine Science》1976,36(3):205-216

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Why chromatic imaging matters     

Joel Sanchez-Bermudez  Florentin Millour  Fabien Baron  Roy van Boekel  Laurent Bourgès  Gilles Duvert  Paulo J. V. Garcia  Nuno Gomes  Karl-Heinz Hofmann  Thomas Henning  Jacob W. Isbell  Bruno Lopez  Alexis Matter  J-Uwe Pott  Dieter Schertl  Eric Thiébaut  Gerd Weigelt  John Young 《Experimental Astronomy》2018,46(3):457-473

During the last two decades, the first generation of beam combiners at the Very Large Telescope Interferometer has proved the importance of optical interferometry for high-angular resolution astrophysical studies in the near- and mid-infrared. With the advent of 4-beam combiners at the VLTI, the u ? v coverage per pointing increases significantly, providing an opportunity to use reconstructed images as powerful scientific tools. Therefore, interferometric imaging is already a key feature of the new generation of VLTI instruments, as well as for other interferometric facilities like CHARA and JWST. It is thus imperative to account for the current image reconstruction capabilities and their expected evolutions in the coming years. Here, we present a general overview of the current situation of optical interferometric image reconstruction with a focus on new wavelength-dependent information, highlighting its main advantages and limitations. As an Appendix we include several cookbooks describing the usage and installation of several state-of-the art image reconstruction packages. To illustrate the current capabilities of the software available to the community, we recovered chromatic images, from simulated MATISSE data, using the MCMC software SQUEEZE. With these images, we aim at showing the importance of selecting good regularization functions and their impact on the reconstruction.  相似文献   

Characteristics of a planar rock slide: Hamersley range, Western Australia     

Karl-Heinz Wyrwoll 《Engineering Geology》1986,22(4):335-348

A large planar rock slide in the Hamersley Range, Western Australia, is described and analysed for possible causes of failure. The general characteristics of the slide are determined by the major joint sets. The rock mass consists predominantly of alternating massive chert members and argillaceous horizons—giving the rock mass a distinctive flaggy appearance. The failure plane dips at 17° and is coincident with a shale horizon. Because of the low inclination of the failure plane factors of safety less than one cannot be obtained from limiting-equilibrium hindcast estimates, unless high joint-water pressures and/or seismic loading are invoked. But while the operation of these two factors cannot be totally ruled out, the field evidence suggests that the necessary conditions for failure were due to the weathering out of shale horizons which could have led to “adjustments” of the rock mass, giving rise to dynamic loading conditions along potential failure planes.  相似文献   

From pastoralism to tourism: The historical impact of changing land use practices in Namaqualand   总被引：1，自引：2，他引：1  

M.T. Hoffman  R.F. Rohde   《Journal of Arid Environments》2007,70(4):641

We use the concept of ecological revolutions to explain the environmental history of Namaqualand, from the advent of pastoralism 2000 years BP, to colonial settlement in the 18th century and finally to the recent trend of de-agrarianization from the middle of the 20th century. Early traveller's records and census data are used to assess changes in the human population of the region and how this affected wildlife and agricultural practices. Pre-colonial indigenous hunter-gatherer (Bushmen) and pastoralist (Khoekhoen) populations in Namaqualand consisted of probably no more than a few thousand individuals. Over the next three centuries, the general population rose steadily to more than 65,000 people but has fallen in recent years. Wildlife appears not to have been abundant in Namaqualand's pre-colonial landscapes and large springbok ‘treks’ were probably a rare event. The number of domestic livestock in Namaqualand peaked in 1957 largely as a result of an increase in the number of sheep which have fallen steadily since this time. Crop production was absent from Namaqualand's pre-colonial landscapes but increased to cover nearly 30,000 ha in the early 1970s. The area under cultivation has declined by nearly two thirds since this time largely as a result of the large-scale abandonment of wheat farming in marginal environments. We touch on differences between the communal areas and private farms, particularly in terms of their human populations and agricultural impact on the land. Repeat landscape photographs support our main findings which suggest that both rocky, upland habitats and rivers have not been transformed substantially by land use practices in Namaqualand. Instead, sandy pediments have borne the brunt of human impacts in the region. Finally, we highlight the beginning of a new ecological revolution in Namaqualand due to changes in the global and national political economy.  相似文献   

The Holocene paleohydrology and climatic history of the northern great sandy desert - fitzroy trough: With special reference to the history of the northwest Australian monsoon     

Karl-Heinz Wyrwoll  Jennifer Hopwood  N. L. McKenzie 《Climatic change》1992,22(1):47-65

The Holocene history of the northwest Australian monsoon is considered in the light of new stratigraphic findings from the southern margin of the monsoon regime. A discussion of the present-day climatology of northwestern Australia and synoptic controls on precipitation in the areas at the southern margin of the monsoon regime is given as background information for the interpretation of stratigraphic findings from swamp and alluvial sequences. The stratigraphic findings point to little change in the intensity of the northwest Australian monsoon since ca. 6.5 ka. A more tentative inference drawn from the field evidence is that the monsoon activity may well have been reduced in this region during the Early Holocene; during this time insolation levels were also reduced. The possible relationship of the northwest Australian monsoon to insolation levels is explored. It is clear that monsoon behavior cannot be accounted for as a simple linear response of monsoon intensity to variations in insolation. Possible controls are discussed with particular emphasis on the plausibility of changes in the damping of convective motions providing the mechanism. Gill's model of heat-induced circulation is used to provide some evidence in favour of this conjecture.  相似文献   

Anticyclonic and cyclonic eddies near the Somali Coast     

Dr. Karl-Heinz Szekielda 《Ocean Dynamics》1971,24(1):26-29

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Modellrechnungen für die freigesetzte Energie bei der Oxydation organischen Materials im Seewasser     

Karl-Heinz Szekielda 《Ocean Dynamics》1967,20(6):265-269

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Evolution of Magnetic Fields in Galaxies with Spiral Structure     

Rohde  R.  Elstner  D.  Rüdiger  G. 《Studia Geophysica et Geodaetica》1998,42(3):382-390

We present simulations of the 3D nonlinear induction equation in order to investigate the temporal evolution of large-scale magnetic fields in spiral galaxies. Our model includes differential rotation, ambipolar diffusion and, based on small-scale turbulence, eddy diffusivity and the tensorial -effect with magnetic feedback. The nonaxisymmetric spiral pattern and – if considered – the vertical stratification of the galaxy are represented in its density and turbulence profile. Neglecting vertical stratification the lifetime and geometry of an initial magnetic field depend on the correlation time of interstellar turbulence _corr . Short correlation times increase the lifetime of the initial magnetic field, but the field is rapidly wound up. Its pitch-angles develop to zero. The magnetic field has disappeared after at most 1 to 1.5 Gyr. A resonance like phenomenon is found by tuning the pattern velocity of the galactic spiral. The simulations then show an exceptional amplification of the magnetic field in the case that the pattern speed and a magnetic drift velocity have similar values. Considering a vertical stratification we achieve sufficiently long living grand-designed magnetic fields excited by dynamo action. The behaviour and geometry of the resulting field is again significantly influenced by the correlation time _corr . Small values of _corr lead to axisymmetric fields with small pitch-angles and field-concentration between the spiral arms. Increasing the correlation time the solutions show larger pitch-angles; and depending on very large correlation times the galactic dynamo rather generates fields clearly within the spiral arms and having a bisymmetric structure.  相似文献