Nonperturbative ocean acoustic tomography inversion

A method for estimating range‐averaged sound‐speed and sound‐slowness profiles from single‐slice tomographic travel‐time measurements is demonstrated. The method directly yields the range average of the equivalent symmetric profile and the asymmetry of the sound channel at the source and receiver. In the absence of independent information, the measurements themselves indicate whether they are consistent with a range‐independent sound channel. The inversion method is applied to a simulated pulse arrival sequence (generated by ray tracing), and the recovered sound speed agrees with that used for the simulation. Using climatology (or other independent information) for the sound speed below the sound‐channel axis would allow an estimate of the range average of the profile above the sound‐channel axis. The method yields the range average of sound slowness without linearization and gives the range average of the sound speed to first order.