HR: 0830h
AN: OS41C-0817    [PDF]
TI: The Global S$_1$ Ocean Tide
AU: * Ray, R D
EM: richard.ray@nasa.gov
AF: Space Geodesy Branch, NASA/GSFC, Code 926, Greenbelt, MD 20771 United States
AU: Egbert, G D
EM: egbert@coas.oregonstate.edu
AF: COAS, Oregon State University, Corvallis, OR 97331 United States
AB: The small S$_1$ ocean tide is caused primarily by diurnal atmospheric pressure loading. Its excitation is therefore unlike any other diurnal tide. The global character of $S_1$ is here determined by numerical modeling and by analysis of Topex/Poseidon satellite altimeter data. The two approaches yield reasonably consistent results, and large ( $>$1\,cm) amplitudes in several regions are further confirmed by comparison with coastal tide gauges. Notwithstanding their excitation differences, S$_1$ and other diurnal tides are found to share several common features, such as relatively large amplitudes in the Arabian Sea, the Sea of Okhotsk, and the Gulf of Alaska. The most noticeable difference is the lack of an S$_1$ Antarctic Kelvin wave. These similarites and differences can be explained in terms of the coherences between near-diurnal oceanic normal modes and the underlying tidal forcings. While gravitational diurnal tidal forces excite primarily a 28-hour Antarctic-Pacific mode, the S$_1$ air tide excites several other near-diurnal modes, none of which has large amplitudes near Antarctica.
DE: 4560 Surface waves and tides (1255)
SC: Ocean Sciences [OS]
MN: 2003 Fall Meeting