|
| |
General Info
|
You are here : |
|
Tomography info/General info
|
|
|
|
Tomography principle
|
|
Ocean tomography uses transmission of acoustic sound waves to deduce the ocean sound speed and velocity structure
(sound speed depends on temperature, pressure and salinity). Instruments moored in the vicinity of the sofar channel
transmit a low frequency coded signal during a few minutes per day. Receivers situated at distances ranging from hundreds
to thousands of kilometers records the signal which is below the background noise level.
Large volumes of ocean are then explored in a few minutes.
Ocean perturbations produce very small changes in travel time.
In order to separate this effect from the change in the distance, due to mooring motion, the instruments positions are
monitored with bottom mounted transponders.
The figure shows a configuration based on 3 transceivers, that cumulates the transmitting and receiving functions.
|
|
|
 |
|
|
|
Recommended readings
|
|
Bold, G. C. S. Chiu, J.
Colosi, B. Cornuelle, B. Dushaw, M. Dzieciuh, A. Forbes, F. Gaillard, J.
Gould, B. Howe, M Lawrence, J. Lynch, D. Menemenlis, J. Mercer, P.
Mikhalevsky, W. Munk, I. Nakano, F. Schott, U. Send, R. Spindel, T. Terre,
P. Worcester, C. Wunsch,
Observing the ocean in the
2000's: A strategy for the role of acoustic tomography in ocean climate
observation.
International conference
on the Ocean Observing system for climate, OCEANOBS 99, Proceedings, 1999.
|
Cornuelle, B., C. Wunsch,
D. Behringer, T. Birdsall, M. Brown, R. Heinmiller, R. Knox, K. Metzger, W. Munk, J. Spiesberger, R. Spindel, D.
Webb,
and P. Worcester, Tomographic maps of the ocean mesoscale,
Part 1,
Pure acoustics, JPO, 15, 133-152, 1985.
|
Dushaw, B. D.,
Inversion of multi-megameter range acoustic data for ocean temperature,
IEE J. Oceanic. Engin., 24, 205-223, 1999.
|
Menemenlis, D., T. Webb,
C. Wunsh, U. Send and C. Hill,
Basin-scale ocean circulation from combined altimetric, tomographic and model data.
Nature, 385, 618-621, 1997.
|
Morawitz, W. M. L., P. L.
Sutton, P. F. Worcester and B. D. Cornuelle, J. F. Lynch and R. Pawlowitcz,
Three-dimensional observations of a deep convective chimney in the Greenland
Sea during winter 1988/89.
JPO, 26, 2316-2343, 1996.
|
Munk, W., P. Worcester and
C. Wunsh,
Ocean Acoustic Tomography.
Cambridge Monographs on Mechanics, 1995.
|
Munk, W., and C. Wunsh,
Ocean acoustic tomography: a scheme for large scale monitoring.
DS, 26A, 123-161, 1979.
|
Send, U., G. Krahmann, D.
Mauury, Y. Desaubies, F. Gaillard, T. Terre, J. Papadakis, M. Taroudakis, E.
Skarsoulis and C. Millot,
Acoustic observation of heat content across the Mediterranean sea.
Nature, 385, 615-617, 1997.
|
Send, U., F. Schott, F. Gaillard, and Y. Desaubies,
Oberservation of a deep convection regime with acoustic tomography,
JGR, 100, 6927-6941, 1995.
|
|
|
|
