Tracking near surface drogues using an acoustic travel time technique in shallow, highly stratified water : problems and observations
Citable URI
https://hdl.handle.net/1912/10253DOI
10.1575/1912/10253Abstract
During July and August of 1980 near surface water velocities of Lake
Huron were measured by tracking drogues, equipped with sonobuoys, using an
acoustic travel time technique. Prior to these experiments difficulties
associated with acoustic ray bending in the shallow, highly stratified
environment were anticipated. Simple models were developed to predict the
errors in drogue position and velocity determination resulting from ray
bending. During the experiments round trip travel times of acoustic pulses
transmitted between three bottom transponders and a transducer (lowered from a
ship) were recorded. These combined with ray diagrams strongly suggested
that, for a separation between the transducer and a bottom transponder of about 1.2 km, pulses which were detected first traveled by two paths, that of
an inflected ray and that of a ray trapped beneath the thermocline. The error
in position and velocity determination associated with these paths was 1 to
2%. Evidence also indicated that increased thermocline depth resulted in
decreased tracking range.
Collections
Suggested Citation
Churchill, J. H. (1981). Tracking near surface drogues using an acoustic travel time technique in shallow, highly stratified water: problems and observations. Woods Hole Oceanographic Institution. https://doi.org/10.1575/1912/10253Related items
Showing items related by title, author, creator and subject.
-
Acoustically and visually tracked drogue measurements of nearsurface water velocities in Lake Huron, plus observations of a coastal upwelling
Churchill, James H.; Pade, Bert H.-G. (Woods Hole Oceanographic Institution, 1981-10)During July and August of 1980 our research group measured nearsurface water velocities near the eastern coast of Lake Huron by tracking drogues using acoustic travel time and compass sighting techniques. The velocity fields ... -
Water velocity measurement from near surface to 110 m depth at deepwater dumpsite #106 using acoustically tracked drogues and conventional current meters
Churchill, James H.; Pade, Bert H.-G.; Peal, Kenneth R. (Woods Hole Oceanographic Institution, 1981-02)A system has been developed recently at W.H.O.I. for tracking nearsurface drogues equipped with sonobuoys using an acoustic navigation system. Surface and submerged drogues of mean depths ranging from 0.15 m to 4.88 m ... -
Measurement of nearsurface current in Cape Cod Bay using sighted drogues
Churchill, James H.; Pade, Bert H.-G. (Woods Hole Oceanographic Institution, 1980-01)During July 16-19, 1979 currents in Cape Cod Bay from the very near surface to 1.8 m were measured by taking simultaneous bearings on submerged drogues from two anchored vessels. The error in drogue position as a function ...