A stochastic model for backscattering on the sea

Backscattering From Trees Explained by Random Propagation Times

“…The motion of the tree branches and leaves gives a random character to the travel time. We have proved that this model is well adapted to the propagation of waves (in acoustics or electromagnetics) [6]- [8]. Z(t) can be split in [16] …”

“…[3][4][5][6][7][8][9][10][11][12][13][14] is very well fitted by a piece of line starting from the last point at the left of the intersection with the horizontal axis (the "decorrelation point"). The remaining data at the right below the horizontal axis are above the line most of the time.…”

“…We consider that the random character is summarized by a random propagation time. This process was successfully applied in other domains of propagation like acoustics, ultrasonics, or sea return [6]- [8]. In a first stage, we revisit the paper by Narayanan et al [1].…”

A stochastic model for acoustic attenuation

“…Developments in Appendix 2 suggest that a coefficient of variation µ proportional to √ α implies no moment for the log-amplitude (see Appendix 3). A Gaussian random transit time is a fair model for explaining the spectra of electromagnetic waves [18][19][20][21]. The product ω 0 σ is large enough to cancel the monochromatic part, because electromagnetic waves are in frequency bands far above the acoustic band.…”

“…Secondly, we show how to explain the random increase of the attenuation which leads to the coefficient of variation, when inhomogeneities or eddies appear in the fluid. This kind of method was successfully applied to other phenomena [17], like backscattering on trees [18], backscattering on sea of radar waves [19], or HF propagation [20].…”