Temporal variation of sound speed in ocean: a comparison between GPS/acoustic and in situ measurements
書誌事項
- 公開日
- 2008-03
- 権利情報
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- https://creativecommons.org/licenses/by/4.0/
- https://creativecommons.org/licenses/by/4.0/
- DOI
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- 10.1186/bf03352785
- 公開者
- Springer Science and Business Media LLC
説明
<jats:title>Abstract</jats:title> <jats:p>The GPS/acoustic technique applied to seafloor geodesy intrinsically measures integrated sound speed along a trajectory of an acoustic signal as well as the position of a seafloor transponder array. We present here a generalized expression of sound speed variation in terms of a traveltime residual normalized to the vertical component. With this expression, residual traveltimes to any seafloor transponders will have a same value regardless of their depths and slant angles. This is valid even for the case having horizontal gradient in sound speed structure; the gradient affects only on positioning of a transponder array and not on the estimate of sound speed just beneath the observation point. We monitored temporal variation of this quantity through a GPS/acoustic survey and compared it with <jats:italic>in situ</jats:italic> expendable bathythermograph (XBT) measurements periodically carried out during the survey. We found that the relative change of the two independent measurements are in good agreement within 5% of the typical amplitude of temporal variation.</jats:p>
収録刊行物
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- Earth, Planets and Space
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Earth, Planets and Space 60 (3), 229-234, 2008-03
Springer Science and Business Media LLC
