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Oceanic residual topography agrees with mantle flow predictions at long wavelengths

Yang, Ting and Moresi, Louis and Müller, R. Dietmar and Gurnis, Michael (2017) Oceanic residual topography agrees with mantle flow predictions at long wavelengths. Geophysical Research Letters, 44 (21). pp. 10896-10906. ISSN 0094-8276. http://resolver.caltech.edu/CaltechAUTHORS:20171024-101304476

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Abstract

Dynamic topography, the surface deflection induced by sublithosheric mantle flow, is an important prediction made by geodynamic models, but there is an apparent disparity between geodynamic model predictions and estimates of residual topography (total topography minus lithospheric and crustal contributions). We generate synthetic global topography fields with different power spectral slopes and spatial patterns to investigate how well the long-wavelength (spherical degrees 1 to 3) components can be recovered from a discrete set of samples where residual topography has been recently estimated. An analysis of synthetic topography, along with observed geoid and gravity anomalies, demonstrates the reliability of signal recovery. Appropriate damping factors, which depend on the maximum degree in the spherical harmonic expansion that is used to fit the samples, must be applied to recover the long-wavelength topography correctly; large damping factors smooth the model excessively and suppress residual topography amplitude and power spectra unrealistically. Recovered long-wavelength residual topographies based on recent oceanic point-wise estimates with different spherical expansion degrees agree with each other and with the predicted dynamic topography from mantle flow models. The peak amplitude of the long-wavelength residual topography from oceanic observations is about 1 km, suggesting an important influence of large-scale deep mantle flow.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1002/2017GL074800DOIArticle
http://onlinelibrary.wiley.com/doi/10.1002/2017GL074800/abstractPublisherArticle
ORCID:
AuthorORCID
Yang, Ting0000-0003-2301-2525
Moresi, Louis0000-0003-3685-174X
Müller, R. Dietmar0000-0002-3334-5764
Gurnis, Michael0000-0003-1704-597X
Additional Information:© 2017 American Geophysical Union. Received 5 JUL 2017; Accepted 17 OCT 2017; Accepted article online 24 OCT 2017; Published online 4 NOV 2017. T.Y. benefitted from the discussion with Judith Sippel on residual topography. The authors thank Malcolm Sambridge and two anonymous reviewers for reading the original manuscript and providing insightful suggestions. M.G. has been supported by the National Science Foundation through EAR-1358646, EAR-1600956, and EAR-1645775 and by Statoil ASA. L.M. and R.D.M. were supported by Australian Research Council grants DP130101946 and IH130200012. Dynamic topography and the recovered long-wavelength residual topography data are listed in the supporting information.
Group:Seismological Laboratory
Funders:
Funding AgencyGrant Number
NSFEAR-1358646
NSFEAR-1600956
NSFEAR-1645775
Statoil ASAUNSPECIFIED
Australian Research CouncilDP130101946
Australian Research CouncilIH130200012
Subject Keywords:residual topography; dynamic topography; long wavelength; amplitude; spatial pattern; damping factors
Record Number:CaltechAUTHORS:20171024-101304476
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20171024-101304476
Official Citation:Yang, T., Moresi, L., Müller, R. D., & Gurnis, M. (2017). Oceanic residual topography agrees with mantle flow predictions at long wavelengths. Geophysical Research Letters, 44, 10,896–10,906. https://doi.org/10.1002/2017GL074800
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:82614
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:24 Oct 2017 17:59
Last Modified:13 Dec 2017 17:51

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