Analysis and modeling of the acoustic tomography signal transmission from Davidson Seamount to Sur Ridge : the forward problem
Onofre, Jose Alberto de Mesquita.
Curtis A. Collins.
MetadataShow full item record
The repeated transmissions of a tomography signal from an autonomous sound source placed on Davidson Seamount was continuously monitored by a bottom- lying, cabled-to-shore receiver on Sur Ridge. To address the signal stability, resolvability and identifiability criteria that determine the applicability of ocean tomography along this path, the data recorded from July 1998 to January 1999 were first processed to obtain the multipath pulse arrival structure and its variability in time. The processed signals showed strong arrivals that were both stable and resolvable. In order to identify the resolved arrivals, acoustic propagation modeling was performed using ray theory in conjunction with measured sound speed and high-resolution bathymetric data. A comparison of the predicted and measured arrival structures show that the observed arrivals were clearly identifiable and were made up of eigenray groups (i.e., eigenray tubes) instead of individual eigenrays. Since the eigenrays within each group were found to have almost identical trajectories through the ocean, the common passage along which the ray group integrates the ocean variability was unambiguous. Consistent with previous CalCOFI observations, the extracted ray group travel time series exhibited dominant oscillations with semidiurnal, diurnal, 8-day, 18-day and 26- day periods, respectively. Using spectral estimation techniques, the travel time variances of these dominant oscillations were quantified. These travel time variances represent direct measurements of the variances of spatially averaged ocean temperatures. Therefore, they are useful for establishing the solution and noise variances for the construction of the inverse solution.
Showing items related by title, author, creator and subject.
Oswald, Ronald G. (Monterey, California. Naval Postgraduate School, 1998-06);This study examines the logic behind choosing variances and the design of forums during the planning of deliberations in non-routine work environments using a Sociotechnical System design approach. This study was accomplished ...
Yang, Wen-Huei (Monterey, California: Naval Postgraduate School, 1990-09);Two approximate interval estimation procedures for mechanical component reliability, P(XY), are developed and their accuracy evaluated by computer simulations. The strength, X, of the component and the stress, Y, applied ...
An analysis of the factors generating the variance between the budgeted and actual operating results of the Naval Aviation Depot at North Island, California Curran, Thomas; Schimpff, Joshua J. (Monterey, California: Naval Postgraduate School, 2008., 2008-06);For six of the past eight years, naval aviation depot-level maintenances activities have encountered operating losses that were not anticipated in the Navy Working Capital Fund (NWCF) budgets. These unanticipated losses ...