Orbital Influence on Earth's Magnetic Field: 100,000-Year Periodicity in Inclination

Abstract

A continuous record of the inclination and intensity of Earth's magnetic field, during the past 2.25 million years, was obtained from a marine sediment core of 42 meters in length. This record reveals the presence of 100,000-year periodicity in inclination and intensity, which suggests that the magnetic field is modulated by orbital eccentricity. The correlation between inclination and intensity shifted from antiphase to in-phase, corresponding to a magnetic polarity change from reversed to normal. To explain the observation, we propose a model in which the strength of the geocentric axial dipole field varies with 100,000-year periodicity, whereas persistent nondipole components do not.

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

“…Recent progress in paleomagnetic studies using ocean sediment cores has enabled further investigations of possible occurrence of geomagnetic field variations on a 100-kyr time scale. Yamazaki and Oda [2002] found a 100 kyr quasi-period in paleomagnetic inclination, and Yamazaki [1999], Yokoyama and Yamazaki [2000], Thouveny et al [2004], Yamazaki and Oda [2004], Yokoyama et al [2007], and Saracco et al [2009] all found similar variations in paleointensity, suggesting that the geomagnetic field may be modulated by the orbital eccentricity.…”

“…[9] We analyzed a paleomagnetic record of core MD982185 (3°05′N, 135°01′E), which covers the period from 30 to 2236 ka [Yamazaki and Oda, 2002]. From paleointensity of the core, Yokoyama et al [2007] extracted geomagnetic variations on a 100 kyr time scale, which have a good correlation with those extracted from a distant core KR0310-PC1 (35°15′N, 175°00′E).…”

“…[11] We also analyzed the normalizer of the paleointensity, saturation isothermal remanent magnetization (SIRM) [Yamazaki and Oda, 2002] to examine lithological contamination in the paleointensity record (Figure 1f).…”

“…The first problem is the statistical significance. Roberts et al [2003] concluded that a ∼100 kyr periodicity in the inclination record of Yamazaki and Oda [2002] is not statistically significant using the wavelet analysis, and similarly Xuan and Channell [2008b] postulated that the orbital frequencies in the paleointensity records of Yamazaki and Oda [2002] and Horng et al…”

Galactic cosmic rays—clouds effect and bifurcation model of the Earth global climate. Part 2. Comparison of theory with experiment

“…(15) in (Rusov et al, 2010)). Necessary experimental data of the magnetization M t and magnetic susceptibility χ t at millennial time scales for the time t ∈ [0, 2.25] million years are obtained by Yamasaki and Oda (2002).…”