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  • 1
    Electronic Resource
    Electronic Resource
    Three-dimensional visualization of orbital forcing and climatic repsonse: Interactively exploring the pacemaker of the ice ages (1996)
    Springer
    International journal of earth sciences 85 (1996), S. 505-512 
    Details
    ISSN: 1437-3262
    Keywords: Paleoclimate ; 3D visualization ; Milankovitch cycles ; Orbital models ; Equatorial Pacific ; Paleoceanography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract Recent developments in continuous core-logging techniques now permit us to recover the high-resolution time series necessary for the detailed spectral analyses of paleoclimatic proxy records. When applied to long records recovered by scientific drilling (5–10 Ma) they enable us to look at the long-term history and evolution of the ocean’s response to orbital forcing. A serious limitation in these studies is the need to display the complex, multidimensional spatial and temporal interactions of the ocean-climate system in an easily comprehensible manner. We have addressed this issue by developing a series 3D visualization tools which permit visualization of the role of the orbital parameters in determining the latitudinal variation of insolation as well as the interactive exploration of multidimensional data sets. The ORBITS tool allows us to visualize the effect of orbital eccentricity, precession, and tilt on the latitudinal distribution of insolation on the earth at the solstices and the equinoxes for any time over the past 5 Ma (for Berger’s orbital model) or 10 Ma (for Laskar’s orbital model). The effect of the orbital parameters on insolation can be viewed individually, in pairs, or all three together. By moving the model steadily through time, the rate at which orbitally induced changes in insolation occur can also be visualized. To look at the ocean’s response to orbital forcing we take the long time series generated from our paleoclimatic proxies and calculate their spectrum over a fixed, but sliding, time window. To view the complex multidimensional relationships found in these evolutionary spectral analyses, we use another interactive 3D data exploration tool developed at the University of New Brunswick (Canada). This tool (FLEDERMAUS) uses a six-degrees-of-freedom input device (BAT) and a series of software modules for color coding, shading, and rendering complex data sets, to allow the user to interactively “fly” through the multidimensional data. Through the use of color, texture, and 3D position, as many as six or seven variables can be explored in a simple and intuitive manner. With special liquid-crystal-display glasses, the scene can be viewed in true “stereo.” We use these tools to explore the relationship between orbital forcing and the response of the benthic isotope and calcium carbonate record at ODP Site 846 (90°W and 5°S) This analysis shows an equatorial Pacific carbonate record which has a large component of linear response to tilt, but little linear response to precession. There is a major shift in response, from a carbonate-dominated response to an isotope (ice volume)-dominated response at approximately 4.5 Ma, and as expected, there is a large nonlinear response at the lower frequencies (400 and 100 kyr) during the past 800 kyr to 1 Ma
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02369005
    Location Call Number Limitation Availability
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    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Three-dimensional visualization of orbital forcing and climatic reponse: interactively exploring the pacemaker of the ice ages (1996)
    Springer
    Geologische Rundschau 85 (1996), S. 505-512 
    Details
    ISSN: 0016-7835
    Keywords: Key words Paleoclimate ; 3D visualization ; Milankovitch cycles ; Orbital models ; Equatorial Pacific ; Paleoceanography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract  Recent developments in continuous core-logging techniques now permit us to recover the high-resolution time series necessary for the detailed spectral analyses of paleoclimatic proxy records. When applied to long records recovered by scientific drilling (5–10 Ma) they enable us to look at the long-term history and evolution of the ocean's response to orbital forcing. A serious limitation in these studies is the need to display the complex, multidimensional spatial and temporal interactions of the ocean-climate system in an easily comprehensible manner. We have addressed this issue by developing a series 3D visualization tools which permit visualization of the role of the orbital parameters in determining the latitudinal variation of insolation as well as the interactive exploration of multidimensional data sets. The ORBITS tool allows us to visualize the effect of orbital eccentricity, precession, and tilt on the latitudinal distribution of insolation on the earth at the solstices and the equinoxes for any time over the past 5 Ma (for Berger's orbital model) or 10 Ma (for Laskar's orbital model). The effect of the orbital parameters on insolation can be viewed individually, in pairs, or all three together. By moving the model steadily through time, the rate at which orbitally induced changes in insolation occur can also be visualized. To look at the ocean's response to orbital forcing we take the long time series generated from our paleoclimatic proxies and calculate their spectrum over a fixed, but sliding, time window. To view the complex multidimensional relationships found in these evolutionary spectral analyses, we use another interactive 3D data exploration tool developed at the University of New Brunswick (Canada). This tool (FLEDERMAUS) uses a six-degrees-of-freedom input device (BAT) and a series of software modules for color coding, shading, and rendering complex data sets, to allow the user to interactively "fly" through the multidimensional data. Through the use of color, texture, and 3D position, as many as six or seven variables can be explored in a simple and intuitive manner. With special liquid-crystal-display glasses, the scene can be viewed in true "stereo." We use these tools to explore the relationship between orbital forcing and the response of the benthic isotope and calcium carbonate record at ODP Site 846 (90°W and 5°S) This analysis shows an equatorial Pacific carbonate record which has a large component of linear response to tilt, but little linear response to precession. There is a major shift in response, from a carbonate-dominated response to an isotope (ice volume)-dominated response at approximately 4.5 Ma, and as expected, there is a large nonlinear response at the lower frequencies (400 and 100 kyr) during the past 800 kyr to 1 Ma
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s005310050091
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Shallow-water imaging multibeam sonars: A new tool for investigating seafloor processes in the coastal zone and on the continental shelf (1996)
    Springer
    Marine geophysical researches 18 (1996), S. 607-629 
    Details
    ISSN: 1573-0581
    Keywords: Multibeam ; sediment classification ; seabed backscatter
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract Hydrographic quality bathymetry and quantitative acoustic backscatter data are now being acquired in shallow water on a routine basis using high frequency multibeam sonars. The data provided by these systems produce hitherto unobtainable information about geomorphology and seafloor geologic processes in the coastal zone and on the continental shelf. Before one can use the multibeam data for hydrography or quantitative acoustic backscatter studies, however, it is essential to be able to correct for systematic errors in the data. For bathymetric data, artifacts common to deep-water systems (roll, refraction, positioning) need to be corrected. In addition, the potentially far greater effects of tides, heave, vessel lift/squat, antenna motion and internal time delays become of increasing importance in shallower water. Such artifacts now cause greater errors in hydrographic data quality than bottom detection. Many of these artifacts are a result of imperfect motion sensing, however, new methods such as differential GPS hold great potential for resolving such limitations. For backscatter data, while the system response is well characterised, significant post processing is required to remove residual effects of imaging geometry, gain adjustments and water column effects. With the removal of these system artifacts and the establishment of a calibrated test site in intertidal regions (where the seabed may be intimately examined by eye) one can build up a sediment classification scheme for routine regional seafloor identification. When properly processed, high frequency multibeam sonar data can provide a view of seafloor geology and geomorphology at resolutions of as little as a few decimetres. Specific applications include quantitative estimation of sediment transport rates in large-scale sediment waves, volume effects of iceberg scouring, extent and style of seafloor mass-wasting and delineation of structural trends in bedrock. In addition, the imagery potentially provides a means of quantitative classification of seafloor lithology, allowing sedimentologists the ability to examine spatial distributions of seabed sediment type without resorting to subjective estimation or prohibitively expensive bottom-sampling programs. Using Simrad EM100 and EM1000 sonars as an example, this paper illustrates the nature and scale of possible artifacts, the necessary post-processing steps and shows specific applications of these sonars.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00313877
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
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