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  • 1
    Online Resource
    Online Resource
    Coastal Acoustic Tomography. (2020)
    San Diego :Elsevier,
    Details
    Keywords: Ocean tomography. ; Electronic books.
    Type of Medium: Online Resource
    Pages: 1 online resource (363 pages)
    Edition: 1st ed.
    ISBN: 9780128189429
    URL: https://ebookcentral.proquest.com/lib/geomar/detail.action?docID=6038312
    DDC: 620.2/5
    Language: English
    Note: Front Cover -- Coastal Acoustic Tomography -- Copyright Page -- Contents -- Preface -- 1 Fundamental Knowledge -- 1.1 Ocean Acoustic Tomography -- 1.1.1 Break Corner (Projected Rays on a Horizontal Slice) -- 1.2 Advancement by Coastal Acoustic Tomography -- 1.3 Coastal-Sea Environmental Monitoring -- 1.4 Coastal-Sea Sound Propagation -- 2 Instrumentation -- 2.1 System Design -- 2.2 Field Deployment Methods -- 2.2.1 Nearshore Platforms -- 2.2.2 Necessity for Permanent Platform -- 2.3 Transmit Signals -- 2.4 Cross-Correlating the Received Data -- 3 Sound Transmission and Reception -- 3.1 One-Dimensional Sound Wave Equation -- 3.2 Sound Transmission Losses -- 3.2.1 Spreading Losses -- 3.2.2 Absorption Losses -- 3.2.3 Bottom Losses -- 3.2.4 Surface Losses -- 3.2.5 Receiving Transmission Sound -- 3.3 Processing the Received Data -- 3.3.1 Ensemble Average -- 3.3.2 Arrival Peaks Identification -- 3.3.3 Processing the Noisy Received Data -- 3.3.4 Multi-Arrival Peak Method -- 4 Range-Average Measurement -- 4.1 Vertical Section Averages -- 4.2 Resolution and Errors -- 4.3 Position Correction -- 4.4 Clock Correction -- 4.5 Conversing From One-Line Current to Along-Channel Current -- 4.6 Conversing From Two-Line Current to North-East Current -- 4.7 Along-Strait Volume Transport and Energy Estimate -- 4.8 Conversing From Sound Speed to Temperature and Salinity -- 4.9 Travel-Time Errors Due to the Station Movements -- 4.10 Errors From the Time Resolution of M Sequence -- 5 Forward Formulation -- 5.1 Sound Wave Equation With a Velocity Field -- 5.2 Ray Simulation -- 5.3 Modal Simulation -- 5.4 Time-of-Flight Equation Along the Rays -- 6 Inversion on a Horizontal Slice -- 6.1 Grid Method -- 6.2 Function Expansion Method -- 6.3 Adding the Coastline Conditions -- 6.4 Validating the Observed Data -- 6.4.1 Comparing the Pre- and Postinversion Results. , 6.4.2 Energy Balance -- 6.4.3 Direct Comparison With the Standard Oceanographic Data -- 7 Inversion on a Vertical Slice -- 7.1 Ray Method -- 7.1.1 Layered Inversion -- 7.1.2 Layered Inversion Deleting Clock Errors -- 7.1.3 Explicit Solution -- 7.2 Acoustic Normal Modes With a Constraint of Narrowband Sound -- 7.3 Function Expansion Using Various Normal Modes -- 7.4 The Three-Dimensional Mapping -- 8 Data Assimilation -- 8.1 Conventional Ensemble Kalman Filter -- 8.1.1 Introductory Remarks -- 8.1.2 Ensemble Kalman Filter Scheme -- 8.1.3 Innovation Vector -- 8.1.4 External Forcing -- 8.1.5 Kalman Gain Smoother -- 8.2 Time-Efficient Ensemble Kalman Filter -- 8.2.1 Time-Invariant Model Error Covariance -- 8.2.2 Assimilation Scheme for Coastal Acoustic Tomography Data -- 9 Applications for Horizontal-Slice Inversion -- 9.1 Nekoseto Channel -- 9.1.1 Oceanographic State -- 9.1.2 Experiment and Methods -- 9.1.3 Differential Travel Times -- 9.1.4 Inversion -- 9.1.5 Mapping Current Velocity Fields -- 9.2 Tokyo Bay -- 9.2.1 Oceanographic State -- 9.2.2 Experiment and Methods -- 9.2.3 Differential Travel Times -- 9.2.4 Inversion -- 9.2.5 Mapping Current Velocity Fields -- 9.3 Kanmon Strait -- 9.3.1 Oceanographic State -- 9.3.2 Experiment and Methods -- 9.3.3 Differential Travel Times -- 9.3.4 Inversion -- 9.3.5 Mapping Current Velocity Fields -- 9.4 Zhitouyang Bay -- 9.4.1 Oceanographic State -- 9.4.2 Experiment and Methods -- 9.4.3 Differential Travel Times -- 9.4.4 Inversion -- 9.4.5 Mapping Current Velocity Fields -- 9.4.6 Tidal Harmonics -- 9.4.7 Rotation of Tidal Currents With the Tidal Phase -- 9.5 Qiongzhou Strait -- 9.5.1 Oceanographic State -- 9.5.2 Experiment and Methods -- 9.5.3 Range-Average Current and Volume Transport -- 9.5.4 Inversion -- 9.5.5 Mapping Current Velocity Fields -- 9.6 Dalian Bay -- 9.6.1 Oceanographic State. , 9.6.2 Experiment and Methods -- 9.6.3 Differential Travel Times -- 9.6.4 Inversion -- 9.6.5 Mapping Current Velocity Fields -- 9.6.6 Validation -- 9.7 Bali Strait (June 2016) -- 9.7.1 Oceanographic State -- 9.7.2 Experiment and Methods -- 9.7.3 Range-Average Currents -- 9.7.4 North-east Currents -- 9.7.5 Along-Strait Volume Transport and Energy Balance -- 9.7.6 Inversion -- 9.7.7 Mapping Current Velocity Fields -- 9.7.8 Specialty of the 3-h Oscillation -- 9.8 Hiroshima Bay -- 9.8.1 Oceanographic State -- 9.8.2 Experiment -- 9.8.3 Position Correction -- 9.8.4 Range-Average Temperature -- 9.8.5 Inversion -- 9.8.6 Mapping Reconstructed Temperature Fields -- 9.8.7 Coastal Upwelling and Diurnal Internal Tides -- 9.8.8 Sea Surface Depression Associated With Upwelling -- 9.8.9 Upwelling Velocity and Mixing Rate -- 10 Applications for Vertical-Slice Inversion -- 10.1 Bali Strait (June 2015) -- 10.1.1 Experiment -- 10.1.2 Ray Simulation -- 10.1.3 Identifying the First Two Arrival Peaks -- 10.1.4 Range-Average Current and Temperature -- 10.1.5 Inversion -- 10.1.6 Profiling the Current and Temperature -- 10.1.7 Power Spectral Densities -- 10.1.8 Nonlinear Tides -- 10.1.9 Concluding Remarks -- 10.2 Luzon Strait -- 10.2.1 Oceanographic State -- 10.2.2 Site and Experiment -- 10.2.3 Data Acquisition and Errors -- 10.2.4 Modal Simulation -- 10.2.5 Identifying Arrival Peaks in the Received Data -- 10.2.6 Profiling the Sound Speed Deviation -- 10.2.7 Retrieving the Periodic Phenomena -- 11 Applications for Data Assimilation -- 11.1 Nekoseto Channel -- 11.1.1 Model and Methods -- 11.1.2 Mapping 2D Current Fields -- 11.1.3 Validation -- 11.2 Kanmon Strait -- 11.2.1 Model and Method -- 11.2.2 Mapping Two-Dimensional Current Velocity Fields -- 11.2.3 Along-Strait Volume Transport -- 11.2.4 Validation -- 11.3 Sanmen Bay -- 11.3.1 Model Site and Data -- 11.3.2 Methods. , 11.3.3 Model -- 11.3.4 Mapping Two-Dimensional Current Velocity Fields -- 11.3.5 Validation -- 11.4 Hiroshima Bay -- 11.4.1 Model -- 11.4.2 Methods -- 11.4.3 Mapping Three-Dimensional Current Velocity and Salinity Fields -- 11.4.4 Volume Transports -- 11.4.5 Transport Continuity and Mixing Fractions -- 12 Modal Function Expansion With Coastline Constraints -- 12.1 Fundamental Remarks -- 12.2 Formulation -- 12.3 Application to Hiroshima Bay -- 12.3.1 Experiment and Methods -- 12.3.2 Observed Data -- 12.3.3 Modal Expansion Functions -- 12.3.4 Mapping Two-Dimensional Current Velocity Fields -- 12.3.5 Validation -- 12.4 Application to Jiaozhou Bay -- 12.4.1 Oceanographic State -- 12.4.2 Experiment and Model -- 12.4.3 Modal Expansion Functions -- 12.4.4 Mapping Two-Dimensional Current Velocity Fields -- 13 Application to Various Fields and Phenomena -- 13.1 Yearly Measurement of the Residual Current -- 13.1.1 Specific Features -- 13.1.2 Experiment -- 13.1.3 Ray Simulation -- 13.1.4 Received Data -- 13.1.5 Along-Channel Current -- 13.1.6 Yearly Variations of the Observed Current and Temperature -- 13.1.7 Residual Current Calculated From Upslope Point Method -- 13.2 Bay With Multiinternal Modes -- 13.2.1 Specific Features -- 13.2.2 Experiment and Methods -- 13.2.3 Range-Average Sound Speed -- 13.2.4 Spectral Analyses -- 13.2.5 Propagation of Internal-Mode Waves -- 13.3 Bay With Resonant Internal Modes -- 13.4 Strait With Internal Solitary Waves -- 13.4.1 Background -- 13.4.2 Experimental Site and Methods -- 13.4.3 Travel Times and Range-Average Temperatures for the Largest Arrival Peak -- 13.4.4 Distance Correction -- 13.4.5 Sound Transmission Data With Multiarrival Peaks -- 13.4.6 Ray Simulation and Inversion -- 13.4.7 Profiling Temperatures -- 13.4.8 Concluding Remarks -- 13.5 River With Tidal Bores -- 13.5.1 Specific Features. , 13.5.2 Experiment and Methods -- 13.5.3 Cross-River Surveys by Shipboard Acoustic Doppler Current Profiler -- 13.5.4 Cross-River Surveys by Coastal Acoustic Tomography -- 13.5.5 River Discharges -- 13.5.6 Concluding Remarks -- 13.6 Large Circular Tank With Omnidirectional Waves and Currents -- 13.6.1 FloWave Circular Tank -- 13.6.2 Simulating Flow Fields -- 13.6.3 Experiment and Methods -- 13.6.4 Identifying Multiarrival Peaks -- 13.6.5 Mapping the Two-Dimensional Current Velocity Fields -- 13.6.6 Remaining Issues -- 14 Mirror-Type Coastal Acoustic Tomography -- 14.1 Introductory Remarks -- 14.2 Mirror-Type Coastal Acoustic Tomography System Design -- 14.3 Enhancing the Positioning Accuracy -- 14.4 Feasibility Experiments -- 14.5 Ray Simulation -- 14.6 Arrival-Peak Identification -- 14.7 Range-Average Currents -- 14.8 Compact Mirror-Type Coastal Acoustic Tomography Array -- 14.9 Further Advancement -- Bibliography -- Index -- Back Cover.
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  • 2
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    Manifestation of the Pacific Decadal Oscillation in the Kuroshio (2010)
    American Geophysical Union
    Details
    Publication Date: 2022-05-25
    Description: Author Posting. © American Geophysical Union, 2009. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 36 (2009): L16602, doi:10.1029/2009GL039216.
    Description: Pacific Decadal Oscillation (PDO) index is strongly correlated with vertically integrated transport carried by the Kuroshio through the East China Sea (ECS). Transport was determined from satellite altimetry calibrated with in situ data and its correlation with PDO index (0.76) is highest at zero lag. Total PDO-correlated transport variation carried by the ECS-Kuroshio and Ryukyu Current is about 4 Sv. In addition, PDO index is strongly negatively correlated, at zero lag, with NCEP wind-stress-curl over the central North Pacific at ECS latitudes. Sverdrup transport, calculated from wind-stress-curl anomalies, is consistent with the observed transport variations. Finally, PDO index and ECS-Kuroshio transport are each negatively correlated with Kuroshio Position Index in the Tokara Strait; this can be explained by a model in which Kuroshio path is steered by topography when transport is low and is inertially controlled when transport is high.
    Description: MA, MW and JP were supported by ONR grant N000140210271. XZ was supported by the National Natural Science Foundation of China under grant 40776021 and the National Basic Research Programs of China under grant 2006CB400603. KK and KC were supported by the Korea EAST-I Program.
    Keywords: Kuroshio ; PDO ; Transport
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: application/pdf
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  • 3
    Electronic Resource
    Electronic Resource
    Dirunal variability and its quantification of subsurface sound scatterers in the western equatorial Pacific (1996)
    Springer
    Journal of oceanography 52 (1996), S. 655-674 
    Details
    ISSN: 1573-868X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract A downwardf-looking acoustic Doppler current profiler (ADCP), suspended by a series of surface and subsurface floats and connecte to an anchroed ship, proided a quite stable platform to measure the, vertical profiles of backscatter strenght *BS) and three components of the velocith from 12 to 22 November 1992 at 1°30′S and 156°15′E, in the Intensive Flux Array (IFA) of TOGA/COARE. While the variability of the horizontal velocity was controlled by the semi-diurnal tide, BS and vertifal velocity were dominated by diurnal variability probably caused by the diel migration of zooplakton. The downward migration occurred early in the moring (0500–0700 in local time) and the upward one late in the afternoon (1700–1900). The average values of about 4 cm s−1 for the sinking and rising speed were estimated from Doppler shift and BS isopleth displacement. The subsurface chlorophyll maximum (SCM) coincident with the top of the thermocline at 80–100 m was also detectable in the BS data during daytime when almost no migrating zooplankton remained in the upper 300 m. Backscatter signals from the SCM and thermocline were separated by corrlating the BS data with the chlorophylla and temperature data. The maximum contribution of the migrating zooplanktion, passively drifting phytoplankton and temperature gradient on BS was estimated to be 14.8, 7.0, 5.1 dB, respectively.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02238326
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  • 4
    Electronic Resource
    Electronic Resource
    Diurnal Cycle of Sound Scatterers and Measurements of Turbidity Using ADCP in Beppu Bay (2000)
    Springer
    Journal of oceanography 56 (2000), S. 559-565 
    Details
    ISSN: 1573-868X
    Keywords: Diurnal cycle of backscatter strength ; Beppu Bay ; bottom-mounted ADCP ; zooplankton ; turbidity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract From September 20 to 22 in 1994, the vertical profiles of echo intensity and three-component velocities were measured with a bottom-mounted 300 kHz broadband acoustic Doppler current profiler (ADCP) in Beppu Bay in the Seto Inland Sea of Japan. A very strong thermocline was observed from 50 to 60 m. A pronounced diurnal cycle of backscatter strength (BS) was found above the thermocline. However, it was not found under the thermocline where there was a lack of dissolved oxygen. We suggest that the diurnal cycle of BS is caused by the vertical migration of zooplankton. The downward and upward migration occurred in early morning and late afternoon, respectively. The migration speeds estimated from BS isopleth displacements were about 1 cm s−1. Further, the contribution of turbidity (Tur) to BS was examined by separating out the effect of migrating zooplankton. There was a significant correlation between BS and turbidity under the thermocline. The maximum contributions of the Tur, migrating zooplankton and non-migrating plankton on BS were estimated at 3, 12, 25 dB, respectively. These data suggest that when using an ADCP to estimate Tur, it is very important to consider carefully the backscatter signal from zooplankton.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1011105228526
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  • 5
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    Assimilation of coastal acoustic tomography data using an unstructured triangular grid ocean model for water with complex coastlines and islands (2017)
    Wiley-Blackwell
    Details
    Publication Date: 2017-08-12
    Description: For the first time, we present the application of an unstructured triangular grid to the Finite-Volume Community Ocean Model using the ensemble Kalman filter scheme, to assimilate coastal acoustic tomography (CAT) data. The fine horizontal and vertical current field structures around the island inside the observation region were both reproduced well. The assimilated depth-averaged velocities had better agreement with the independent acoustic Doppler current profiler (ADCP) data than the velocities obtained by inversion and simulation. The root mean square difference (RMSD) between depth-averaged current velocities obtained by data assimilation and those obtained by ADCPs was 0.07 m s −1 , which was less than the corresponding difference obtained by inversion and simulation (0.12 m s −1 and 0.17 m s −1 , respectively). The assimilated vertical layer velocities also exhibited better agreement with ADCP than the velocities obtained by simulation. RMSDs between assimilated and ADCP data in vertical layers ranged from 0.02 to 0.14 m s −1 , while RMSDs between simulation and ADCP data ranged from 0.08 to 0.27 m s −1 . These results indicate that assimilation had the highest accuracy. Sensitivity experiments involving the elimination of sound transmission lines showed that missing data had less impact on assimilation than on inversion. Sensitivity experiments involving the elimination of CAT stations showed that the assimilation with four CAT stations was the relatively economical and reasonable procedure in this experiment. These results indicate that, compared with inversion and simulation, data assimilation of CAT data with an unstructured triangular grid is more effective in reconstructing the current field.
    Print ISSN: 0148-0227
    Topics: Geosciences , Physics
    Published by Wiley-Blackwell on behalf of American Geophysical Union (AGU).
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