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| Titel |
Stochastic Heterogeneity Mapping around a Mediterranean salt lens |
| VerfasserIn |
G. G. Buffett, C. A. Hurich, E. A. Vsemirnova, R. W. Hobbs, V. Sallarès, R. Carbonell, D. Klaeschen, B. Biescas |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1812-0784
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| Digitales Dokument |
URL |
| Erschienen |
In: Ocean Science ; 6, no. 1 ; Nr. 6, no. 1 (2010-03-31), S.423-429 |
| Datensatznummer |
250003370
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| Publikation (Nr.) |
 copernicus.org/os-6-423-2010.pdf |
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| Zusammenfassung |
| We present the first application of Stochastic Heterogeneity Mapping based
on the band-limited von Kármán function to a seismic reflection
stack of a Mediterranean water eddy (meddy), a large salt lens of
Mediterranean water. This process extracts two stochastic parameters
directly from the reflectivity field of the seismic data: the Hurst number,
which ranges from 0 to 1, and the correlation length (scale length). Lower
Hurst numbers represent a richer range of high wavenumbers and correspond to
a broader range of heterogeneity in reflection events. The Hurst number
estimate for the top of the meddy (0.39) compares well with recent
theoretical work, which required values between 0.25 and 0.5 to model
internal wave surfaces in open ocean conditions based on simulating a
Garrett-Munk spectrum (GM76) slope of −2. The scale lengths obtained do not
fit as well to seismic reflection events as those used in other studies to
model internal waves. We suggest two explanations for this discrepancy: (1)
due to the fact that the stochastic parameters are derived from the
reflectivity field rather than the impedance field the estimated scale
lengths may be underestimated, as has been reported; and (2) because the
meddy seismic image is a two-dimensional slice of a complex and dynamic
three-dimensional object, the derived scale lengths are biased to the
direction of flow. Nonetheless, varying stochastic parameters, which
correspond to different spectral slopes in the Garrett-Munk spectrum
(horizontal wavenumber spectrum), can provide an estimate of different
internal wave scales from seismic data alone. We hence introduce Stochastic
Heterogeneity Mapping as a novel tool in physical oceanography. |
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