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Measuring the Kuroshio Current with ocean acoustic tomography
Naokazu Taniguchi1, Chen-Fen Huang, Arata Kaneko
1Graduate School of Engineering, Hiroshima University, Hiroshima 739-8527, Japan.
The Journal of the Acoustical Society of America
|October 15, 2013
Summary
Ocean acoustic tomography (OAT) successfully profiled Kuroshio Current, revealing strong upper-layer currents that weakened with depth. Results align with acoustic Doppler current profiler and ocean model predictions.
Area of Science:
- Oceanography
- Acoustic physics
Background:
- Ocean current profiling is crucial for understanding marine dynamics.
- Ocean Acoustic Tomography (OAT) offers a non-invasive method for measuring underwater currents.
Purpose of the Study:
- To profile ocean currents in the Kuroshio Current using OAT.
- To validate OAT methods against established techniques and ocean models.
Main Methods:
- Reciprocal sound pulse transmission between two acoustic stations (48 km apart).
- Analysis of received signals divided into ray groups to determine differential travel times.
- Reconstruction of vertical current profiles using explicit solution and inversion with regularization.
Main Results:
- Strong currents were observed in the upper 200 m, weakening significantly by 500 m depth.
- OAT results showed good agreement with Acoustic Doppler Current Profiler (ADCP) data in the upper 150 m.
- Temporal variations in currents correlated well with predictions from the Hybrid Coordinate Ocean Model (HYCOM).
Conclusions:
- OAT is an effective method for reconstructing vertical ocean current profiles.
- The study validated the accuracy of OAT in the Kuroshio Current.
- Observed current dynamics were consistent with large-scale ocean modeling efforts.
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