Perturbations from a source in a three-layer atmosphere

✍ Scribed by A.M. Ter-Krikorov

• Publisher: Elsevier Science
• Year: 2002
• Tongue: English
• Weight: 442 KB
• Volume: 66
• Category: Article
• ISSN: 0021-8928
• DOI: 10.1016/s0021-8928(02)00008-4

✦ Synopsis

The problem of internal waves, excited by a point source in a three-layer, initially unperturbed, atmosphere is investigated in a linear formulation. It is assumed that the vertical displacements and the velocities of the particles change continuously at the boundaries of the layers and that the Brunt-Vais& frequency is constant in each layer but suffers discontinuities at the boundaries of the layers. The solution, found using integral transforms, is expressed in terms of double integrals of multiple-valued analytic functions. The integral representation for the perturbations in the middle layer does not enable asymptotic methods to be used directly to obtain an approximate description of the behaviour of the solution at long times. It is transformed into finite sums of single-valued integrals which, in a certain sense, represent the various modes of oscillation which arise. Modes making the major contribution to the perturbation are investigated by the stationary phase method. Particular surfaces are found in the neighbourhood of which the amplitudes of the oscillations decay weakly with time. A problem on perturbations from a source in a two-layer atmosphere was investigated earlier in [l]. A study of the case of a three-layer atmosphere is of interest since the middle layer acts as a waveguide.