Service interruption on Monday 11 July from 12:30 to 13:00: all the sites of the CCSD (HAL, EpiSciences, SciencesConf, AureHAL) will be inaccessible (network hardware connection).
Skip to Main content Skip to Navigation
Journal articles

The flow at the Earth's core-mantle boundary under weak prior constraints

Abstract : Prior information in ill-posed inverse problem is of critical importance because it is conditioning the posterior solution and its associated variability. The problem of determining the flow evolving at the Earth's core-mantle boundary through magnetic field models derived from satellite or observatory data is no exception to the rule. This study aims to estimate what information can be extracted on the velocity field at the core-mantle boundary, when the frozen flux equation is inverted under very weakly informative, but realistic, prior constraints. Instead of imposing a converging spectrum to the flow, we simply assume that its poloidal and toroidal energy spectra are characterized by power laws. The parameters of the spectra, namely, their magnitudes, and slopes are unknown. The connection between the velocity field, its spectra parameters, and the magnetic field model is established through the Bayesian formulation of the problem. Working in two steps, we determined the time-averaged spectra of the flow within the 2001-2009.5 period, as well as the flow itself and its associated uncertainties in 2005.0. According to the spectra we obtained, we can conclude that the large-scale approximation of the velocity field is not an appropriate assumption within the time window we considered. For the flow itself, we show that although it is dominated by its equatorial symmetric component, it is very unlikely to be perfectly symmetric. We also demonstrate that its geostrophic state is questioned in different locations of the outer core.
Document type :
Journal articles
Complete list of metadata
Contributor : Nathalie POTHIER Connect in order to contact the contributor
Submitted on : Sunday, February 20, 2022 - 12:57:11 PM
Last modification on : Tuesday, February 22, 2022 - 3:36:01 AM
Long-term archiving on: : Saturday, May 21, 2022 - 6:11:19 PM


JGR Solid Earth - 2016 - Baere...
Publisher files allowed on an open archive


Distributed under a Creative Commons Attribution 4.0 International License



Julien Baerenzung, Matthias Holschneider, Vincent Lesur. The flow at the Earth's core-mantle boundary under weak prior constraints. Journal of Geophysical Research : Solid Earth, American Geophysical Union, 2016, 121, pp.1343-1364. ⟨10.1002/2015JB012464⟩. ⟨insu-03581670⟩



Record views


Files downloads