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For purposes of atmospheric correction of satellite images, the problem of estimating the distance from the cloud gap center at which the effect from cloudiness on the satellite image can be neglected is posed. The Monte Carlo method with the backward simulation scheme is used. The value for the radius of the gap in continuous cloudiness at which the influence of clouds changes the received radiation intensity by 10% has been obtained. Dependences of the received intensity on the gap radius have been obtained and explained.

Three algorithms of the Monte Carlo method for the calculation of the pulse reaction in channels of laser sensing and communication are considered: the local estimation algorithm, double local estimation algorithm, and proposed modified double local estimation algorithm. Results of testing the algorithms and their comparison are shown. For the case of a homogeneous medium, the performances of the algorithms are compared. The comparison shows conditions for which the proposed algorithm has the advantage over the double local estimation algorithm. The contribution of double, triple, and higher multiplicity scattering is estimated. The high contribution of multiple scattering justifies the applicability of the Monte Carlo method for solving such problems.

The problem of allowance for polarization in statistical simulation of satellite imaging of the surface of the Earth in the optical wavelength range is considered. It is shown that the neglect of polarizing properties of radiation can lead to significant errors when retrieving the reflection coefficients of low-reflectivity surfaces.

Near-ground propagation of monochromatic acoustic radiation at frequencies of 300, 1000, 2000, and 3150 Hz along atmospheric paths up to 100 m long is investigated experimentally and theoretically depending on altitudes of the acoustic source and receiver. The experiment was carried out at the experimental site of the Institute of Monitoring of Climatic and Ecological Systems (IMCES) using a specially developed setup. The dependence of the recorded sound pressure level on the propagation path length and initial signal power is analyzed. The theoretical analysis is performed by the Monte Carlo method using the local estimation algorithm developed by the authors. The comparison of the experimental and theoretical results shows their satisfactory agreement, which indicates the effectiveness of the proposed algorithm and its applicability to predicting the near-ground sound propagation.

A description of a software package for reconstructing the distribution of the reflection coefficient of the Earth’s surface, as well as procedures developed for a considerable reduction of the computation time, is presented. By an example of a test region in the western coast of Africa, a comparison has been performed for results obtained by the proposed algorithm, the algorithm of homogeneous correction, and the standard MOD09 NASA algorithm. The correlation coefficients of results for this test region are as follows: between the new algorithm and homogeneity correction algorithm, 0.999; between the new algorithm and the MOD09 algorithm, 0.984.

In the report a review is given and new results obtained at the IAO SB RAS on problems of optical communication on scattered laser radiation in the atmosphere and water media are presented. Examples of its implementation are presented under various optical-geometrical conditions and with high quality of field experiments at distances up to 70 km in the atmosphere and up to 25 m in the water medium.

The problem of taking into account the effect of polarization is considered for correction of satellite images of the Erath’s surface in the visible wavelength range for the distorting effect of the atmosphere. A program complex for calculation of the radiation components forming the satellite images has been developed with and without allowance for radiation polarization in the approximation of the homogeneous surface. Conditions are considered under which the neglect of polarization properties of radiation can lead to significant errors in reconstruction of the reflection coefficients of weakly reflecting surfaces.

Algorithms for retrieving the reflection coefficient of the Earth’s surface from satellite measurement data are proposed. They permit one to take into account the main components of the radiation forming the Earth’s surface image with different degrees of accuracy. The algorithms include solving the radiative transfer equation by use of the theory of linear systems, the Monte Carlo method, approximation formulas, and the image isoplanarity criterion. The algorithms were validated based on numerical experiments and comparisons with calculation results obtained by other authors.

The paper considers the methods for theoretical and experimental study of bistatic optical communication schemes. A laboratory model of an optoelectronic communication system has been developed for experimental studies. Copper-vapor laser radiation at a wavelength of 510 nm was used as a source of signals. Test demonstration experiments were performed in the real atmosphere through atmospheric channels with a reflecting surface and a dense nonstationary aerosol-molecular structure. For theoretical studies, software means were developed for numerical statistical estimation of the energy and transfer characteristics of the bistatic atmospheric communication channels by the Monte Carlo method.

Time distribution of the monostatic sodar signal intensity has been obtained in the report with allowance for the contribution of multiply scattered radiation. Dependences of the sodar signal intensity on its parameters and atmospheric meteorological conditions are analyzed.

An algorithm for reconstructing the Earth’s surface reflection coefficients from the data of MODIS satellite measurements is considered. For six channels of the MODIS device in the visible and near-IR ranges, the influence of a 10% error in the assignment of the aerosol and molecular extinction on the accuracy of reconstructing of the Earth’s surface reflection coefficients is estimated. A comparison of this error with the error of reconstructing the reflection coefficient for a surface area in the Tomsk Region by the suggested algorithm and the algorithm MOD09 is performed. Results of comparison show that the error in assignment of the input optical parameters can be the main source of the error of the correction algorithms for wavelengths 0.4–0.85 μm. For the channel centered at 1.25 μm the error of the algorithms is much greater than the error caused by a 10 % error of assignment of the optical parameters.

Problems of application of the statistical simulation (Monte Carlo) method for solving fundamental and applied problems of atmospheric optics and acoustics at the V. E. Zuev Institute of Atmospheric Optics of the SB RAS are discussed in the present work. The most significant results obtained in the study of imaging of objects located on the Earth’s surface, in the atmosphere, and in space for ground-based and satellite observations aimed at the development of means for atmospheric correction of data of satellite passive sensing of the Earth’s surface, investigation of bistatic atmospheric optical communication channels, and estimation of the energy characteristics of acoustic radiation propagating through the turbulent atmosphere and sodar signals are presented.

The problem of estimating the influence of homogeneous cloudiness on the signal received during observation of the Earth’s surface from a satellite system is considered for the Lambert reflection from the Earth’s surface. In calculations the Monte Carlo method with backward scheme of simulation of trajectories is used. The gap radii at which the influence of cloudiness decreases down to 10 % of the received radiance are found. A dependence of the radiance on the gap radius is obtained and explained.

The problem of polarization account in statistical simulation of the process of satellite imaging of the Earth’s surface in the visible and near-IR range of wavelengths is considered. The complex of algorithms is developed on the basis of the Monte Carlo method that allows reflection coefficient of the Earth’s surface to be reconstructed in the homogeneous surface approximation with and without allowance for radiation polarization. Test examples are presented that prove the correctness of the algorithmic implementation. It is demonstrated that account of polarization can be an integral part of the atmospheric correction algorithm, in particular, for weakly reflecting surfaces.

We discuss the results of mathematical simulation of a field experiment on determining the contrast of an object’s image on the background of the sky in the UV wavelength range. The influence of the aerosol component of the atmosphere on this characteristic of image quality is analyzed. For experimental data, we used the field measurements carried out in the Institute of Atmospheric Optics, Siberian Branch of the Russian Academy of Sciences. Mathematical simulation was performed by the Monte Carlo method. The model of the atmosphere was specified by a generator of optical models based on LOWTRAN-7. Comparison of the results of mathematical simulation and measurement data shows almost full coincidence in the character of the variation of the normalized contrast of the object’s image on the background of the sky depending on the optical length of the path between the object and the optical system.

An algorithm is proposed to simulate a point spread function by the Monte Carlo method in order to represent external channel formation in the spherical model system of the “atmosphere-earth surface.” A new way of defining isoplanarity zones of optically homogeneous extended objects is described. We demonstrate that image restoration with a specified error for these objects when they are observed on the earth’s surface from space by an ideal optical system can determine a definite point spread function set.

A new algorithm of the Monte Carlo method is suggested for the statistical estimation at any arbitrary point of the atmosphere of the intensity of the visible radiation caused by the reflection of solar light fluxes from the Earth’s spherical surface. The algorithm allows for the albedo of the Earth’s optically homogeneous surface to be taken into account beyond the scheme of the statistical modeling of the trajectories of photons wandering in the medium.

The method of direct simulation of photon trajectories in a stochastic medium is compared with the method of closed equations suggested by G. A. Titov. A comparison is performed for the model of the stochastic medium in the form of a cloudy field of constant thickness comprising rectangular clouds whose boundaries are determined by a stationary Poisson flow of points. It is demonstrated that the difference between the calculated results can reach 20–30%; however, in some cases (for some sets of initial data) the difference is limited by 5% irrespective of the cloud cover index.

The question of the application of parallel computations for solving the problem of atmospheric correction of satellite images is considered. It is shown that parallelization of algorithms of the Monte Carlo method with respect to packets of trajectories makes it possible to significantly reduce the computation time.

For atmospheric correction of satellite images, the problem is formulated to estimate the distance from a cloud at which its influence on the satellite image of the Earth surface can be neglected. The Monte Carlo method of conjugate trajectories is used. The gap radius in the field of continuous cloudiness at which the influence of the cloudy medium on the received signal intensity does not exceed 10 % is obtained. It is revealed that for the Lambert law of radiation reflection from the Earth surface, the curve of the dependence of the received signal intensity on the gap radius has a maximum caused by the opposite influence of light scattering by the cloudy medium and radiation reflection by the surface (adjacency effect). To further generalize the examined problem to a stochastic cloud field, the method of direct simulation of photon trajectories in a stochastic medium is compared with G. A. Titov’s method of closed equations in the gap vicinity. A comparison is carried out with the model of the stochastic medium in the form of a cloud field of constant geometric thickness consisting of rectangular clouds whose boundaries are determined by the stationary Poisson flow of points. It is demonstrated that results of calculations can differ at most by 20‒30 %; however, in some cases (for some sets of initial data), the difference for the entire region of cloud cover indices is within 7 %. © (2015) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

In the present work, the problem of propagation of monochromatic acoustic radiation in the lower 500-meter layer of the plain stratified moving turbulent atmosphere is solved by the Monte Carlo method. The influence of the parameters of models of the outer scales of temperature and dynamic turbulence on the intensity of transmitted acoustic radiation intensity is investigated.

In this study, problems of statistical simulation of acoustic radiation propagation in the lower atmosphere along the vertical and horizontal paths by the Monte Carlo method and construction of the acoustic model of the atmosphere are considered. The influence of the geometry of problem being solved, radiation frequency, angle of source divergence, and outer scale of turbulence on the transmitted radiation intensity is discussed with allowance for the contribution of multiply scattered radiation.

Characteristics of object images observed through scattering media with an active vision system with wide receiving angle operating in the mode of spatial selection are estimated using the Monte Carlo method. The effect of optical and geometrical conditions of observation on the contrast in images of reflecting objects is considered. Interpretation is given to the obtained dependences. The main results obtained in this work are the following. A suit of programs of the Monte Carlo method has been developed for statistical simulation of the imaging process in pulsed active vision systems with spatial selection. In the framework of the considered formulation of the problem, the contrast of the object image against the scattered background and the surface lying under the observation path exceeds the level of 0.8 up to the optical depth of the medium τ ≈ 4 and exceeds 0.4 up to τ ≈ 5. The process of multiple scattering determines, to the significant degree, not only the backscattering, but also the useful signal and, in particular, the intensity of the non-scattered radiation reflected by the object and recorded by the receiver. The sample of the ladar for car application was created and got testing.

Pulsed responses of optical communication channels with reflections from underlying surfaces have been investigated by the Monte Carlo method, together with the radiation fluxes reflected from and transmitted through a scattering medium. The effect of reflection model, geometric parameters of transmitting and signal recording systems, and optical density of the medium on the responses has been analyzed. The contribution of singly scattered radiation to the pulsed response of the communication channel has been estimated.

We present the results of statistical simulation of upward flux of thermal scattered radiation in a wide range of variations of characteristics of aerosol extinction and scattering both in the atmospheric boundary layer and in the stratosphere. We carry out this simulation in case of spatially homogeneous Lambertian surface using the Monte Carlo method. We consider the effect of aerosol upon scattered radiance, characteristics of the adjacency effect as well as the accuracy of both the single scattering approximation and the conservative scattering model.© (1994) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.