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| Titel |
Using multi-scale methods for sensitivity analysis in potential field interpretation |
| VerfasserIn |
I. Einarsson, J. Kusche |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250027421
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| Zusammenfassung |
| It is a common practise to use spherical harmonic coefficients and the associated global spectrum to analyse the sensitivity of time-variable potential field data, e.g. those provided by the GRACE satellite mission. When studying a signals detectability by a satellite mission with known error characteristics, the conventional method has disadvantages. While delivering meaningful comparisons for
global signals, the global nature of the spherical harmonic functions makes it
unsuitable for strongly localised signals. In such cases, the global spectrum will
compare the energy of locally concentrated signal to the globally distributed
energy of the measurement errors, strongly underestimating the signal-to-noise
ratios.
We study alternative methods for sensitivity analysis. Since we want to maintain
the spectral nature of the spherical harmonics, to be able to distinguish between
signals of different scales [a pointwise comparison is meaningless, instead...] we
concentrate on methods offering a spatio-spectral compromise. After a brief foray
into the optimally concentrated band-limited Slepian's functions, the main effort
goes into investigating wavelets on the sphere. Using Monte Carlo methods, we
propagate the errror characteristics of the GFZ-RL04 GRACE solution from the
original spherical harmonic coefficients onto a wavelet basis. Using these, we
study the detectability of locally concentrated events in Earth's gravity field,
using the great Sumatra-Andaman earthquake of 2004 as a test-case. |
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