TIDES AND TSUNAMIS 



Bernard D. Zetler 



National Oceanic and Atmospheric Administration 

 Atlantic Oceanographic and Meteorological Laboratories 

 Physical Oceanography Laboratory 

 Miami, Florida 33130 



Abstract 



Although tides and tsunamis are both shallow water 

 waves, it does not follow that they are equally amenable 

 to an observational program using an orbiting altimeter 

 on a satellite. Therefore, the physics of each is con- 

 sidered in an effort to evaluate the feasibility of 

 successful measurement from space. Because tide analysis 

 requires a multiplicity of orbits, absolute accuracy is 

 important but a constant bias is acceptable. A numerical 

 feasibility investigation using a hypothetical satellite 

 orbit, real tide observations, and sequentially increased 

 levels of white noise has been conducted to study the de- 

 gradation of the tidal harmonic constants caused by adding 

 noise to the tide data. Tsunami waves, possibly a foot 

 high and one hundred miles long, must be measured in in- 

 dividual orbits, thus requiring high relative resolution. 



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