Assessing links between geo/paleo-magnetic observations and the geodynamo process
Abstract
Establishing links between geomagnetic observations and the physics of the geodynamo process gives crucial clues for understanding the dynamics and evolution of Earths core. Recent high-resolution modeling suggests that the force balance approaching Earths core conditions in the bulk is Quasi-Geostrophic (QG) at leading order, with a Magneto-Archimedean-Coriolis (MAC) balance at the next order. Concurrently, several criteria have been proposed to quantify the level of agreement between numerical model outputs and observations of the geomagnetic and paleomagnetic field at the core-mantle boundary (CMB). Here, we consider the links between the dynamics of Earths core revealed by the force balances in the bulk, the observed low-degree geomagnetic field at the CMB, and dipole field variations revealed by paleomagnetism. With a large suite of numerical dynamo simulation, three criteria are computed: 1. Force balance spectra for elucidating the relevant regimes of dynamics; 2. Misfit values between simulated magnetic field at the CMB and the recent geomagnetic field using the compliance criteria (Christensen et al., 2010); 3. The quality of paleomagnetic modeling (QPM) criteria for assessing the misfit between simulated and paleomagnetic fields. By analyzing the trends between force balances and compliance criteria, we can access the conditions for dynamo action satisfying both physics and observations.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2021
- Bibcode:
- 2021AGUFMDI34B..08N