A Probabilistic Assessment of the Next Geomagnetic Reversal
| Autor: | William B. Davis, Bruce A. Buffett |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
Paleomagnetism
010504 meteorology & atmospheric sciences Stochastic modelling Geophysics 010502 geochemistry & geophysics 01 natural sciences Physics::Geophysics Geomagnetic reversal Moment (mathematics) Dipole Amplitude Earth's magnetic field General Earth and Planetary Sciences Magnetic dipole Geology 0105 earth and related environmental sciences |
| Zdroj: | Geophysical Research Letters. 45:1845-1850 |
| ISSN: | 0094-8276 |
| Popis: | Author(s): Buffett, B; Davis, W | Abstract: Deterministic forecasts for the next geomagnetic reversal are not feasible due to large uncertainties in the present-day state of the Earth's core. A more practical approach relies on probabilistic assessments using paleomagnetic observations to characterize the amplitude of fluctuations in the geomagnetic dipole. We use paleomagnetic observations for the past 2nMyr to construct a stochastic model for the axial dipole field and apply well-established methods to evaluate the probability of the next geomagnetic reversal as a function of time. For a present-day axial dipole moment of 7.6 × 1022nAnm2, the probability of the dipole entering a reversed state is less than 2% after 20nkyr. This probability rises to 11% after 50nkyr. An imminent geomagnetic reversal is not supported by paleomagnetic observations. The current rate of decline in the dipole moment is unusual but within the natural variability predicted by the stochastic model. |
| Databáze: | OpenAIRE |
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