Normal mode sound propagation in an ocean with random narrow‐band surface waves

1993 ◽  
Vol 94 (1) ◽  
pp. 279-292 ◽  
Author(s):  
G. V. Anand ◽  
Mathews K. George
Keyword(s):  
Surface Waves ◽  
Normal Mode ◽  
Sound Propagation ◽  
Narrow Band

Laser generation of narrow‐band surface waves

1992 ◽  
Vol 92 (5) ◽  
pp. 2527-2531 ◽  
Author(s):  
Jin Huang ◽  
Sridhar Krishnaswamy ◽  
Jan D. Achenbach
Keyword(s):  
Surface Waves ◽  
Narrow Band ◽  
Laser Generation

scholarly journals Automated detection and association of surface waves

1994 ◽  
Vol 37 (3) ◽  
Author(s):  
R. G. North ◽  
C. R. D. Woodgold
Keyword(s):  
Surface Waves ◽  
Group Velocity ◽  
Rayleigh Waves ◽  
Arrival Time ◽  
Narrow Band ◽  
Broad Band ◽  
Detection Algorithm ◽  
Automated Detection ◽  
Short Period ◽  
Group Velocities

An algorithm for the automatic detection and association of surface waves has been developed and tested over an 18 month interval on broad band data from the Yellowknife array (YKA). The detection algorithm uses a conventional STA/LTA scheme on data that have been narrow band filtered at 20 s periods and a test is then applied to identify dispersion. An average of 9 surface waves are detected daily using this technique. Beamforming is applied to determine the arrival azimuth; at a nonarray station this could be provided by poIarization analysis. The detected surface waves are associated daily with the events located by the short period array at Yellowknife, and later with the events listed in the USGS NEIC Monthly Summaries. Association requires matching both arrival time and azimuth of the Rayleigh waves. Regional calibration of group velocity and azimuth is required. . Large variations in both group velocity and azimuth corrections were found, as an example, signals from events in Fiji Tonga arrive with apparent group velocities of 2.9 3.5 krn/s and azimuths from 5 to + 40 degrees clockwise from true (great circle) azimuth, whereas signals from Kuriles Kamchatka have velocities of 2.4 2.9 km/s and azimuths off by 35 to 0 degrees. After applying the regional corrections, surface waves are considered associated if the arrival time matches to within 0.25 km/s in apparent group velocity and the azimuth is within 30 degrees of the median expected. Over the 18 month period studied, 32% of the automatically detected surface waves were associated with events located by the Yellowknife short period array, and 34% (1591) with NEIC events; there is about 70% overlap between the two sets of events. Had the automatic detections been reported to the USGS, YKA would have ranked second (after LZH) in terms of numbers of associated surface waves for the study period of April 1991 to September 1992.

Remote laser generation of narrow-band surface waves through optical fibers

1999 ◽  
Vol 46 (6) ◽  
pp. 1551-1557 ◽  
Author(s):  
F.L. Di Scalea ◽  
T.P. Berndt ◽  
J.B. Spicer ◽  
B.B. Djordjevic
Keyword(s):  
Surface Waves ◽  
Optical Fibers ◽  
Narrow Band ◽  
Laser Generation

MHD surface waves in high- and low-beta plasmas. Part 1. Normal-mode solutions

1989 ◽  
Vol 42 (1) ◽  
pp. 75-89 ◽  
Author(s):  
Z. E. Musielak ◽  
S. T. Suess
Keyword(s):  
Magnetic Field ◽  
Surface Waves ◽  
Normal Mode ◽  
General Structure ◽  
Normal Modes ◽  
Resonant Absorption ◽  
Normal Surface ◽  
Phase Mixing ◽  
Cold Plasmas ◽  
The Waves

Since the first paper by Barston (1964) on electrostatic oscillations in inhomogeneous cold plasmas, it has been commonly accepted that all finite layers with a continuous profile in pressure, density and magnetic field cannot support normal surface waves but instead the waves always decay through phase mixing (also called resonant absorption). Here we reanalyse the problem by studying a compressible current sheet of a general structure with rotation of the magnetic field included. We find that all inhomogeneous layers considered in the high-β plasma limit do not support normal modes. However, in the limit of a low-β plasma there are some cases when normal-mode solutions are recovered. The latter means that the process of resonant absorption is not common for all inhomogeneous layers.

Sound propagation in shallow water with surface waves

2004 ◽  
Vol 116 (4) ◽  
pp. 2550-2550
Author(s):  
Chris T. Tindle ◽  
Grant B. Deane
Keyword(s):  
Surface Waves ◽  
Shallow Water ◽  
Sound Propagation

Shallow water sound propagation with surface waves

2005 ◽  
Vol 117 (5) ◽  
pp. 2783-2794 ◽  
Author(s):  
Chris T. Tindle ◽  
Grant B. Deane
Keyword(s):  
Surface Waves ◽  
Shallow Water ◽  
Sound Propagation
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