User menu

Accès à distance ? S'identifier sur le proxy UCLouvain | Saint-Louis

The coupling between inertial and rotational eigenmodes in planets with liquid cores

Primary tabs

download
  • Open access
  • PDF
  • 3.86 M
Triana, Santiago Andrés [Royal Observatory of Belgium, Brussels, Belgium] Rekier, Jérémy [Royal Observatory of Belgium, Brussels, Belgium] Trinh, Antony [Royal Observatory of Belgium, Brussels, Belgium] Dehant, Véronique [UCL]

The Earth is a rapidly rotating body. The centrifugal pull makes its shape resemblea flattened ellipsoid and Coriolis forces support waves in its fluid core, known asinertial waves. These waves can lead to global oscillations, or modes, of the fluid.Periodic variations of the Earth’s rotation axis (nutations) can lead to an exchange ofangular momentum between the mantle and the fluid core and excite these inertialmodes. In addition to viscous torques that exist regardless of the shape of theboundaries, the small flattening of the core-mantle boundary (CMB) allows inertialmodes to exert pressure torques on the mantle. These torques effectively couple therigid-body dynamics of the Earth with the fluid dynamics of the fluid core. Herewe present the first high resolution numerical model that solves simultaneously therigid body dynamics of the mantle and the Navier-Stokes equation for the liquidcore. This method takes naturally into account dissipative processes in the fluidthat are ignored in current nutation models. We find that the Free Core Nutation(FCN) mode, mostly a toroidal fluid flow if the mantle has a large moment of inertia,enters into resonance with nearby modes if the mantle’s moment of inertia is reduced.These mode interactions seem to be completely analogous to the ones discovered bySchmitt (2006) in a uniformly rotating ellipsoid with varying flattening

Document type Article de périodique (Journal article) – Article de recherche
Access type Accès libre
Publication date 2019
Language Anglais
Journal information "Geophysical Journal International" - Vol. 218, no.2, p. 1071-1086 (2019)
Peer reviewed yes
Publisher Oxford University Press (OUP)
issn 0956-540X
e-issn 1365-246X
Publication status Publié
Affiliation UCL - SST/ELI/ELIC - Earth & Climate
Keywords Geochemistry and Petrology ; Geophysics
Links
  1. Amestoy Patrick R., Duff Iain S., L'Excellent Jean-Yves, Koster Jacko, A Fully Asynchronous Multifrontal Solver Using Distributed Dynamic Scheduling, 10.1137/s0895479899358194
  2. Amestoy Patrick R., Guermouche Abdou, L’Excellent Jean-Yves, Pralet Stéphane, Hybrid scheduling for the parallel solution of linear systems, 10.1016/j.parco.2005.07.004
  3. Buffett Bruce A., Tidal dissipation and the strength of the Earth’s internal magnetic field, 10.1038/nature09643
  4. Dalcin Lisandro D., Paz Rodrigo R., Kler Pablo A., Cosimo Alejandro, Parallel distributed computing using Python, 10.1016/j.advwatres.2011.04.013
  5. Greenspan, The Theory of Rotating Fluids (1968)
  6. Hernandez Vicente, Roman Jose E., Vidal Vicente, SLEPc : A scalable and flexible toolkit for the solution of eigenvalue problems, 10.1145/1089014.1089019
  7. Hollerbach R., Kerswell R. R., Oscillatory internal shear layers in rotating and precessing flows, 10.1017/s0022112095003338
  8. Johansson H. T., Forssén C., Fast and Accurate Evaluation of Wigner 3$j$, 6$j$, and 9$j$ Symbols Using Prime Factorization and Multiword Integer Arithmetic, 10.1137/15m1021908
  9. Koot L., Dumberry M., Rivoldini A., De Viron O., Dehant V., Constraints on the coupling at the core-mantle and inner core boundaries inferred from nutation observations : Nutation constraints on CMB and ICB coupling, 10.1111/j.1365-246x.2010.04711.x
  10. Le Bars Michael, Cébron David, Le Gal Patrice, Flows Driven by Libration, Precession, and Tides, 10.1146/annurev-fluid-010814-014556
  11. Lin Yufeng, Ogilvie Gordon I., Tidal interactions in spin–orbit misaligned systems, 10.1093/mnras/stx540
  12. Mathews P. M., Herring T. A., Buffett B. A., Modeling of nutation and precession: New nutation series for nonrigid Earth and insights into the Earth's interior : NEW NUTATION SERIES AND THE EARTH'S INTERIOR, 10.1029/2001jb000390
  13. Olver Sheehan, Townsend Alex, A Fast and Well-Conditioned Spectral Method, 10.1137/120865458
  14. Phinney Robert A., Burridge Robert, Representation of the Elastic - Gravitational Excitation of a Spherical Earth Model by Generalized Spherical Harmonics, 10.1111/j.1365-246x.1973.tb02407.x
  15. Rekier J, Trinh A, Triana S A, Dehant V, Inertial modes in near-spherical geometries, 10.1093/gji/ggy465
  16. RIEUTORD M., VALDETTARO L., Inertial waves in a rotating spherical shell, 10.1017/s0022112097005491
  17. Rieutord M., Valdettaro L., Axisymmetric inertial modes in a spherical shell at low Ekman numbers, 10.1017/jfm.2018.201
  18. RIEUTORD M., GEORGEOT B., VALDETTARO L., Inertial waves in a rotating spherical shell: attractors and asymptotic spectrum, 10.1017/s0022112001003718
  19. Rogister Yves, Valette Bernard, Influence of liquid core dynamics on rotational modes, 10.1111/j.1365-246x.2008.03996.x
  20. Roman (2017)
  21. SCHMITT D., Numerical study of viscous modes in a rotating spheroid, 10.1017/s0022112006002497
  22. ZHANG KEKE, LIAO XINHAO, EARNSHAW PAUL, On inertial waves and oscillations in a rapidly rotating spheroid, 10.1017/s0022112003007456
Bibliographic reference Triana, Santiago Andrés ; Rekier, Jérémy ; Trinh, Antony ; Dehant, Véronique. The coupling between inertial and rotational eigenmodes in planets with liquid cores. In: Geophysical Journal International, Vol. 218, no.2, p. 1071-1086 (2019)
Permanent URL http://hdl.handle.net/2078.1/220961