ASA 124th Meeting New Orleans 1992 October

2pAO2. Relative arrival tomographic reconstruction using drifting receivers and a ship-board source.

J. Lynch

R. Pawlowicz

T. Duda

A. Newhall

Appl. Ocean Phys. and Eng. Dept., Woods Hole Oceanogr. Inst., Woods Hole, MA 02543

Rather than testing ocean imaging with accurately located and timed acoustic transmission equipment, a study of the quality of images produced with sonobuoy-type drifting receivers and ship-lowered sources is presented. The imprecise location and timing information means that the only information available is the relative timing of multipath (ray-type) arrivals. Accuracy of relative arrival time measurement is presumed to be 5 ms and positioning is to 1 km. The forward model is a ray trace through the background, and the basis set has various vertical forms. Three array sizes are considered, 100, 350, and 1000 km. Deployments on these different scales will have different oceanographic goals. The distribution of successfully mapped variance at all scales smaller than the array dimension will be shown. The appropriate array dimension, relative to the sound-speed field correlation length, will be discussed. Comparisons with more standard quick-survey methods (e.g., AXBT drops) will be considered.