Could the energy near the FCN and the FICN be explained by luni-solar or atmospheric forcing?

Details Could the energy near the FCN and the FICN be explained by luni-solar or atmospheric forcing? Could the energy near the FCN and the FICN be explained by luni-solar or atmospheric forcing?

Aug 1997

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1997geoji.130..535d&link_type=abstract

Geophysical Journal International, Vol. 130, No. 2, p. 535 - 546

Physics

1

Earth Rotation: Nutation

Scientific paper

The observed time-series of precession/nutation show residuals with respect to an empirical model based on the rigid Earth theoretical nutations and a frequency-dependent transfer function with resonances to the Earth's normal modes. These residuals display energy mainly in the frequency domain around 430 and 500 days in the inertial frame. In this frequency band, the energy is possibly related to two normal-mode frequencies: the free core nutation (FCN) and the free inner core nutation (FICN). The authors examine the possibility of obtaining this energy from the resonance effect induced by a luni-solar (or planetary) forcing, or by an atmospheric forcing at a frequency very close to these Earth free nutations. The amplification factor due to the resonance is computed from an analytical formula expressed in the case of a simplified three-layer ellipsoidal rotating Earth (with an elastic inner core, a liquid outer core and an elastic mantle), as well as the empirical formula based on the analysis of VLBI observations. For the tidal forcing, the theoretical results do not show any resonance at the level of precision examined but it is still possible to find one frequency near the FCN or FICN frequencies which could be excited. In contrast, for the atmospheric pressure the level of energy needed could be obtained from the diurnal pressure, depending on the noise level of the Earth's global pressure. The authors also show that the combination of three waves can explain the observed decrease of energy with time.

Affiliated with

Also associated with

No associations

Rating

Could the energy near the FCN and the FICN be explained by luni-solar or atmospheric forcing? does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Could the energy near the FCN and the FICN be explained by luni-solar or atmospheric forcing?, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Could the energy near the FCN and the FICN be explained by luni-solar or atmospheric forcing? will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-805235