HR: 12:05h
AN: U41C-08 INVITED     [PDF]
TI: Decadal variations in length of day: a probe of the CMB?
AU: * Holme, R
EM: holme@liv.ac.uk
AF: Richard Holme, Deptartment of Earth and Ocean Sciences, University of Liverpool 4 Brownlow St, Liverpool, L69 3GP United Kingdom
AB: Decadal variations in length of day are believed to result from the exchange of angular momentum between the fluid core and the solid mantle. Based on the theory of torsional oscillations, a good match has been found between modelled changes in core angular momentum and observed Earth rotation, at least for the period 1900-1990. However, the mechanism by which angular momentum is exchanged is still not clear. I discuss the difficulties with using geomagnetic observations to constrain this process, and consider what information on the CMB region may be gleaned. I reconsider the period prior to 1900, to see what can be constrained from this period. Recent dedicated magnetic satellites have resulted in high resolution models of the geomagnetic field and its temporal variation for the current epoch. I consider what these models can tell us about core processes, both now and in the future.
DE: 1239 Rotational variations
DE: 1507 Core processes (8115)
DE: 1560 Time variations--secular and long term
DE: 8115 Core processes (1507)
SC: U
MN: 2003 Fall Meeting