Abstract
The mathematical basis for a method to invert modal ocean acoustic tomography measurements without explicitly assuming an initial sound-speed profile is described. The method is based on determining the group and phase travel times for each vertical slice through the tomographic region. The group travel times are determined directly as the measurements of modal pulse travel time. The phase travel times are determined by resolving the cycle ambiguities in the phase measurements with constraints connecting the group and phase travel times. Standard tomographic techniques then determine the modal group and phase speeds within the tomographic region, and Abel transforms can be used to determine the symmetric part (the difference between the upper and lower profiles) of the sound channel. As with ray tomography, modal tomographic measurements supply no information about the antisymmetric part of the sound channel (the average of the upper and lower profiles), but determining the lower part of the sound channel can supply the missing information. The lower part of the sound channel can be estimated from climatology or by using arrays to determine local sound-speed profiles from local modal properties and interpolating into the interior of the tomographic region.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
