HR: 08:05h
AN: S11C-01 INVITED     [Abstracts]
TI: Methods for Detecting Microseism-Generating Ocean Waves
AU: * Longuet-Higgins, M
EM: mlonguet@ucsd.edu
AF: Institute for Nonlinear Science, Univ. of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0402 United States
AB: The likeliest field conditions for the generation of oceanic microseisms are the occurrence in an ocean wavenumber spectrum of energetic wave components travelling in opposite directions. This produces ${\em partial \; standing \; waves}$ at the sea surface. Besides the possibility of some reflection of wave energy from a steep coastline, the hindcasting of wave spectra (using the observed wind field) together with ${\em in \; situ}$ wave measurements with directional buoys, has demonstrated that such conditions are much more common over deep water than was previously thought. A simplified theory of the effect, confirmed by laboratory experiments, will be presented. The occurrence of partial standing waves also explains the generation of low-frequency sound (microbaroms) in the atmosphere, as has been shown by certain acoustical observations due to Evers and Haak (2001). Lastly, a new method will be proposed for detecting partial standing waves by aerial observations and by altimeter records from orbiting satellites.
DE: 7255 Surface waves and free oscillations
DE: 7200 SEISMOLOGY
DE: 4259 Ocean acoustics
DE: 3025 Marine seismics (0935)
SC: Seismology [S]
MN: 2004 AGU Fall Meeting