Calculations of ocean-acoustic fluctuations for use in tomography of internal waves

In order to use observations of the bias and variance of travel time, the length scale of acoustic coherence in depth, and the spreading of the acoustic pulse as information about the internal-wave field in the ocean (all for identifiable rays at long range), a reliable method of calculation of these quantities in the presence of a specific internal-wave model must be made. Attempts to use analytical methods having proven unreliable for long range, except for the variance of travel time; there are two possibilities: (1) restrict tomography of identifiable rays to travel-time variance; or (2) use simulation by parabolic equation to calculate expected values. The former is restricted and the latter is computer intensive. The needed resources for the latter will be discussed.