Abstract:

The Polar frontal zone is known to have the highest contrast between properties of the divided water masses in Nordic seas. Acoustically, it is a strongly range-dependent environment. Numerical simulations of acoustic propagation in the frequency range of 20--200 Hz have been conducted for typical cases by using the IFD-PE and KRAKEN codes. The adiabaticity is strongly frequency dependent. For lower frequency, the inverted results of the frontal parameters based on the adiabatic modal travel time and modal horizontal refraction data can be obtained analytically using a simple ``few parameter model'' proposed by Kuz'kin [Acoust. Phys. 39(4), 402 (1993)]. The possibility of estimating the frontal parameters for a more complex realistic model will also be discussed. [Work supported by ONR and NOAA.]