Alexander G. Voronovich

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A theoretical model that describes the power of a scattered Global Positioning System (GPS) signal as a function of geometrical and environmental parameters has been developed. This model is based on a bistatic radar equation derived using the geometric optics limit of the Kirchhoff approximation. The waveform (i.e., the time-delayed power obtained in the(More)
A small-slope approximation (SSA) is used for numerical calculations of a radar backscattering cross section of the ocean surface for both Kuand C-bands for various wind speeds and incident angles. Both the lowest order of the SSA and the one that includes the next-order correction to it are considered. The calculations were made by assuming the(More)
The full utilization of satellite-based passive microwave imagery for weather forecasting rests on the ability to assimilate radiances into numerical weather prediction (NWP) models for highly scattering and absorbing hydrometeor states. State vector updates need to be performed rapidly enough to maintain pace with the sensor data stream and require, in(More)
In 1998–1999, a comprehensive low-frequency long-range sound propagation experiment was carried out by the North Pacific Acoustic Laboratory ~NPAL!. In this paper, the data recorded during the experiment by a billboard acoustic array were used to compute the horizontal refraction of the arriving acoustic signals using both rayand mode-based approaches. The(More)
The mean value and the coherence function of a sound field propagating in an oceanic waveguide with random inhomogeneities are important statistical characteristics of this field, which are needed for many practical applications. Closed equations for the coherence function were obtained in many works for both two dimensional and three dimensional(More)
Second moments of mode amplitudes at fixed frequency as a function of separations in mode number, time, and horizontal distance are investigated using mode-based transport equations and Monte Carlo simulation. These second moments are used to study full-field acoustic coherence, including depth separations. Calculations for low-order modes between 50 and(More)
Ocean gravity waves can be rather steep and even breaking depending on wind speed. Analytical modeling of both the evolution of such strongly nonlinear waves and electromagnetic (EM) scattering from them is currently impossible. At the same time, numerical modeling of these processes poses a significant challenge in terms of the complexity of codes and(More)