Geomagnetic 100‐kyr variation excited by a change in the Earth's orbital eccentricity

Abstract

[1] Geomagnetic secular variations on a time scale of 10-100 kyr have important implications regarding the energy source of the geomagnetic field. Some high-quality paleomagnetic records from marine sediment cores show quasi-periodic variations having a time scale close to that of the Earth's orbital eccentricity. We analyzed a paleomagnetic record of core MD982185 from the equatorial Pacific and the Earth's eccentricity for the last 2.2 m.y. utilizing wavelet analysis. Variations in the geomagnetic vertical component were synchronous with those in the first derivative of the eccentricity, implying that the geomagnetic variations are excited by changes in the eccentricity. Citation: Yokoyama, Y., T. Yamazaki, and H. Oda (2010), Geomagnetic 100-kyr variation excited by a change in the Earth's orbital eccentricity, Geophys.

Eccentricity-paced geomagnetic field and monsoon rainfall variations over the last 870 kyr

“…However, whether the geomagnetic field intensity is modulated by Earth’s orbital parameters, or it interacts with paleoclimate change remains controversial ( 2 ). Previous studies reveal that Earth’s orbital signals such as eccentricity and obliquity cycles have been observed in the records of paleomagnetic inclination/intensity from marine sediments ( 3 – 7 ), implying a likely relationship between geomagnetic field and orbital parameters. However, other studies have argued that sedimentary records of paleomagnetic intensity (relative paleointensity) may be contaminated by climate and/or sediment diagenetic processes ( 8 – 10 ), leaving the relationship between climate and the geomagnetic field inconclusive.…”

Magnetic Field Variation Caused by Rotational Speed Change in a Magnetohydrodynamic Dynamo

“…The strength of the geomagnetic field has experienced temporal variations of several tens of percent, which is discovered in recent several hundreds of thousands of years [14][15][16][17][18]. Climatic changes with ice and non-ice ages might cause these variations [19] through Earth's rotational speed or length-of-day (LOD) variations [20][21][22].…”