South China Sea internal tide/internal waves-impact on the temporal variability of horizontal array gain at 276 Hz
Orr, Marshall H.
Pasewark, Bruce H.
Wolf, Stephen N.
Lynch, James F.
MetadataShow full item record
The temporal variability of the spatial coherence of an acoustic signal received on a bottomed horizontal array has been calculated for 276-Hz narrow-band signals. A conventional plane wave beamformer was applied to the received signals. The temporal variability of the array's omnipower, beam power, and array gain are related to variability in the sound-speed field. The spectral characteristics of array omnipower are nonstationary and changed as the spectral characteristics of the temperature field varied. The array omnipower and beam-power variability tracked each other in time and varied by as much as 15 dB over time intervals as short as 7 min. Array gain varied up to 5 dB and usually tracked the omnipower variability. A contiguous 24-h section of data is discussed in detail. This data section is from a time period during which the high-frequency fluid dynamic perturbation of the sound-speed field was of smaller amplitude than other sections of the 16-d data set. Consequently, this section of data sets an upper bound for the realizable array gain. The temporal variability of array gain and spatial coherence at times appears to be correlated with environmental perturbation of the sound-speed field, but are also correlated with changes in the signal-to-noise ratio. The data was acquired during the Office of Naval Research's South China Sea Asian Seas International Acoustics Experiment. The 465-m 32-channel horizontal array was placed on the bottom in 120 m of water at the South China Sea shelf break. The acoustic source was moored in 114 m of water /spl sim/19 km from the receiving array.
The article of record as published may be found at https://doi.org/10.1109/JOE.2004.836794
Showing items related by title, author, creator and subject.
Castro, Rubén; Mascarenhas, Affonso S.; Durazo, Reginaldo; Collins, Curtis A. (2000);Se describe la variabilidad estacional en la entrada al Golfo de California utilizando datos de CTD en una sección a través de la entrada al golfo, la cual fue ocupada en ocho ocasiones entre 1992 y 1998. Se encontró que ...
Ramp, Steven R.; Tang, Tswen Yung; Duda, Timothy F.; Lynch, James F.; Liu, Antony; Chiu, Ching-Sang; Bahr, Frederick L.; Kim, Hyoung-Rok; Yang, Ying-Jang (IEEE, 2004-10);A moored array of current, temperature, conductivity, and pressure sensors was deployed across the Chinese continental shelf and slope in support of the Asian Seas International Acoustics Experiment. The goal of the ...
Chen, Yuchun; Chu, Peter C.; Wang, Guihua (2002);The autocorrelation functions of temperature and salinity in the three basins (Ulleung, Japan, and Yamato Basins) of the Japan/East Sea are computed using the U.S. Navy’s Master Oceanographic Observational Dataset for ...