Some developments that are planned to be included into an information system for atmospheric applications are considered. A fast algorithm to retrieve temperature, pressure, and mixing ration altitude profiles of the atmosphere composition from high-resolution spectra that are recorded by the interferometer of a new generation on the satellite platform is discussed. The algorithm is distinguished by the analytical computation of the derivatives, entered the inverse calculations, and by the regularization technique. Validating this code, the MITI's IMG data, recorded on board NASDA's ADEOS satellite, is used in order to retrieve a realistic temperature profile of the low atmosphere up to altitudes of 20 km.

Integral transmission functions in near infrared region of spectrum were extracted from the benchmark calculations of the solar radiation fluxes for the mid-latitude summer atmosphere. Their comparison with the values obtained from empirical formulas shows a good agreement. Hence, the transmission functions resulting from both ways can be used in climate modeling.

At present, the tendency of global warming of the earth climate is observed. The climate depends on even small changes of radiative processes in the atmosphere. According to recent conceptions, the 'green house' effect can be connected with the increasing concentration of minor gaseous components, such as CO₂, CO, CH₄, and freons, therewith the contribution of the letter is comparable to that of CO₂. A radiance transfer through the atmosphere is performed through spectral transmission windows, in which one of the basic roles belongs to water vapor continuum absorption. Different recent models of continuum absorption, based on the experimental data, are considered here. The long-wave radiance flux calculation is made on the basis of these models. It is shown that the error of the radiative fluxes calculation in the transmission windows is of the same order as the contribution of some atmospheric minor gaseous constituents and often exceeds it. Therefore, the accurate analytical expressions, describing the water continuum absorption and accounting for the nonlinear dependence of the absorption on humidity, temperature, wavelength and other factors, are needed.

Relative transmission of radiation P in the minimum of the 2724-cm₁ HDO band has been analyzed in two cases: a) for solar radiation and different air masses m (slant paths); b) globar as the artificial source of radiation in the ground air layer (horizontal paths with a length of 1.4 km). A technique for estimation of precipitated water w_z (cm) in the vertical atmospheric column with accuracy of about 10 percent has been suggested. Calibration curve P (s_z x m) calculated from the dependence of P on w_o - precipitated water of the ground air layer - is used.

Transparency spectra I of solar radiation in the range v = 750 — 1250 -cm1 have been analyzed. By coincidence of I obtained in winter at close air masses but different values of water vapor content, spectral dependence of absorption of the solar radiation in H20 continuum was has been determined. It is shown, that the results of the present work can be used to estimate ofthe aerosol contribution to the continuum extinction in the 750 — 1250 -cm' transparency window.

Absorption coefficient of the water vapor was obtained in laser measurements in Ref. 1 in spectral region 930 - 990 cm₁ at temperatures from 263 K to 300 K. In this paper, the water vapor selective absorption in this spectral region is calculated and subtracted from the experimental data₁ to determine the 'experimental' continuum absorption. Continuum absorption calculated using some empirical relations in compared with the 'experimental' one to study its temperature dependence.

Series of calculations of the solar radiation fluxes were done by the Monte Carlo Method with rigorous treatment of gaseous absorption. The spectral ranges for which gaseous absorption should be considered in case of measuring fluxes with the K-3 spectrometer are selected. Our analysis demonstrated that the absorption by 5 gases, namely H₂O, O₃, O₂, NO₂ and NO₃ is significant for the examined measurements.

The characteristics of the solar spectrum at the top of the atmosphere and near the ground surface in different seasons are presented. The solar radiation flux in the photosynthetic active regime (PAR) is considered at the normal incidence of solar rays on the ground surface with respect to the top of the atmosphere. The transparency of the atmosphere at the latitude of 42 degree(s) during 1993-1997 and April until October 1993 is presented. Extinction of the direct PAR under different conditions of aerosol pollution is considered.

The theory of linked groupings of vibrational-rotational interactions in molecules has been applied for the construction of the infinite series for effective dipole moments of one quantum vibrational transitions. The necessary and sufficient symmetric selection rules for forbidden transitions dipole moments have been developed. All aspects of the removal of prohibition from fully symmetric fundamentals of nonpolar molecules have been investigated. Mechanisms of activation of other inactive fundamentals of nonpolar molecules are considered also. Ab initio calculation of dipole moment function and the evaluation of the effective transition dipole moments for CH₄ molecule are presented.

The two modern conceptions of the perturbation theory and the series theory have been applied to the analysis of diatomic molecular spectra. The first is linked with ordering of the perturbations according to the limiting grouping of vibrational-rotational interactions. The second is linked with summation of series on the base of nonlinear sequence transformations. The results for vibrational and rotational dependencies of effective dipole moments for diatomic molecules have been presented for the first time in nonpolynomial forms.

The common origin of the operators of the forms (formula available in paper)in effective molecular vibration-rotation Hamiltonian for the quasidegenerate vibrational states are discussed on the base of the theory of linked groupings of vibrational-rotational interactions. It is shown that any operator contribution into effective Hamiltonian of the effective operators of the observables may be presented in the form (formula available in paper)approaching (formula available in paper)equals (formula available in paper). The values h (formula available in paper)are considered as the grouping uncertainties. On the base of grouping uncertainties for (g) approaching (g') implies (W) approaching (M), where the (W) and (M) are limiting groupings developed by J.L. Watson (m+(epsilon) n) and V.M. Mikhailov ((epsilon) m+n) ((epsilon) approaching 0), classification of the accidental resonances on the types (i) strong(S), (ii) middle(m), (iii) weak(w) has been developed for the first time. The Taylor approximation of rotational dependencies of accidental resonances and axiomatic representation of these dependencies by analytical functions have been considered. The following molecules are the first studied: Methane type, CO₂, H₂ type.

The effective rotational Hamiltonian for the stretching modes of H₂X molecules have been analyzed on the base of the two conceptions: site-symmetry and linked groupings of vibrational rotational interactions. The site-symmetry of the effective Hamiltonian for the region of (v₁, v₃) dyad of H₂X molecules at the condition m_H << m_x is reduced to C_s symmetry, as compared with C₂V symmetry of the initial Hamiltonian. For the first time for H₂X molecule with strong Coriolis-type accidental resonance it had been shown that the parameters of effective Hamiltonian depend on groupings of vibrational- rotational interactions. This dependence from weak via middle to strong resonances has the trend to decrease. For H₂S molecule at the local mode limit, the effective Hamiltonian for Coriolis-type resonance don't depend on the groupings of initial Hamiltonian expansions. Two ways of experimental energy levels assignment for some vibrational polyads of H₂S molecule, based on the symmetry reduction conception have been presented.

The vibrational translational relaxation time of 001 state of ozone in binary mixtures with noble gases (He, Ne, Ar, Kr, Xe) was measured from the phase shift of the photoacoustic signal relative to the amplitude-modulated radiation of the CO₂ laser used for excitation of O₃. A three-level kinetic model of O₃ is used to fit the experimental and calculational data of the phase shift and to determine the vibrational relaxation rate coefficient. The vibrational relaxation rate constants for 001 state were obtained corresponding to the deexcitation by the direct way of the 000 state and in two steps through the 010 state. Dependences of the relaxation rate constants on molecular mass and polarizability of buffer gas are presented. Estimates of vibrational relaxation rate constants in the Landau-Teller approximation for various molecular masses and polarizabilities of buffer gas were performed.

Data on vibrational spectra of polycyclic aromatic hydrocarbons in gas phase are of considerable interest for solving the astrophysical problems. Results of experimental and theoretical investigations of spectral characteristics: positions, widths, absorption cross-sections and oscillator strengths of anthracene molecule bands in the 800 - 3200 cm ^-1 region are given. Comparison of experimental and calculated intensity distribution in a separate absorption band of anthracene vapors shows that a decisive factor in forming a profile is free rotation of molecules.

Values of the binary absorption coefficients are obtained for the region of Herzberg photodissociation continuum in mixtures of oxygen with various foreign gases X, where X - Ar, Kr, Xe, N₂, N₂O, CH₄, C₃H₈, CO₂, NH₃, NF₃, SF₆, CF₄, C₂F₆, C₃F₈, CF₃H, CF₃Cl, CF₃Br, CF₂ClH, CF₂Cl₂ - group I (the ionization potential of molecules >= 11 eV) and C₂H₄, CF₃I, C₂F₅I - group II (the ionization potential < 11 eV). The induced absorption of the mixtures of O₂ with gases from group I is found to result from the Herzberg III band of oxygen. The obtained regular dependence of the intensity of induced absorption in an O₂ - X pair on the ionization potential of a molecule X, confirms the hypothesis that excited electronic states of the ionic type of the molecular pair serve as the main intensity source for the Herzberg III band. The long-wavelength wing of the charge transfer band of the O₂ - X pair is shown to contribute to the induced absorption of the mixtures of O₂ with gases from group II.

Measurements and calculations of the oxygen pressure-induced shift coefficients for more than 100 water vapor absorption lines of the (000) - (011) and (000) - (110) bands have been performed. Experimental data on line shift coefficients were obtained from analysis of H₂O - O₂ room temperature absorption spectra at 11 different pressures of O₂ over the range 148.5 Torr to 3800.4 Torr, using a Fourier transform spectrometer with spectral resolution of 0.0007 cm^-1 and an optical pathlength of 84.05 m. Calculations of line shift coefficients were performed using the Anderson semiclassical impact theory.

The water vapor line broadening coefficients in the (010) - (000) band induced by nitrogen pressure have been measured with FT - spectrometer of Paris University at the spectral resolution 0.005 cm ^-1 for lines with angular moment of upper states up to 18. The method of spectral line parameters retrieving is presented. Calculations were made using Anderson theory. The calculated line widths agree satisfactory with measured values.

About 150 lines of the (nu) ₂ band of H₂O were measured by Fourier transform spectrometer of Paris VI University, with a spectral resolution of 0.005 cm ^-1. It was found that some of spectrally unresolved doublets reveal a significant collision line narrowing as the pressure of the buffer gas (N₂) increases. Experimental data on such doublet line profiles was processed with a specially developed theory in the hard collision model under the assumption of strong collision line mixing of unresolved doublet lines. The pressure line broadening coefficients also with the line narrowing parameters were obtained. The observed difference in pressure broadening coefficients of the considered doublet (nu) ₁ equals 1879.0194 and (nu) ₂ equals 1879.0195 cm^-1 and nearby singlet lines was explained on the basis of the developed theory.

The present study considered the structural and spectral features of (H₂O)₇ complex and trends in water complexes (H₂O)_n, equals 2 - 7. HF calculations have been done. The vibrational spectra of water complexes show blue shifts in intramolecular bends and red shifts in the OH stretches with respect to monomer water. There is elongation of a bridge OH_b bond that participates in the hydrogen bonding. The R (O...O) distance decreases with the increasing complex size.

The new analysis of water vapor high resolution spectra in 13200 - 16500 cm ^-1 region has been done using conventional scheme of the effective Hamiltonians in the Pade-Borel approximants representation. About 30 percent of new energy levels has been derived after the spectrum identification including the highest ever observed (0 10 0) [7 0 7] level. An alternative method of the spectrum identification using recent ab initio and variational calculations is discussed.

If the size of atmospheric plasma is sufficiently large, its resonance radiation can be efficiently absorbed by its atoms and molecules being in the ground and excited states. Such atmospheric plasma is adiabatic. This paper develops the adiabatic theory of plasma recombination in the atmosphere. Dependence of the recombination coefficient on the temperature of electrons is obtained. Singular points of the solution of equations are interpreted as evidence that long- living matastable states of plasma exist. Parameters of such states are presented. Ball lightening and plasma of night ionosphere are considered as examples.

The three-dimensional LES model with explicit microphysics and a 3D Monte Carlo radiation transfer model were used to study the influence of vertical variability of extinction coefficient on the mean, variance, and two-dimensional fields of upward, downward, and horizontal radiative fluxes of overcast stratocumulus clouds. Within the cloud layer, the vertical stratification of extinction coefficient has considerable effect on the means and variances of the fluxes. At the cloud boundaries, the spatial distributions of the fluxes depend strongly on the vertical inhomogeneity of extinction coefficient.

Influence of effects, caused by stochastic cloud geometry, on integrated radiative characteristics of one-layer broken clouds has been studied. It is shown that the difference between the mean fluxes of shortwave radiation in cumulus and equivalent stratus clouds may amount to tens of percent. An increase of the height of cloud top boundary causes a 10- 15% increase in albedo at the top of the atmosphere, while leaving transmittance at the surface level unaffected. The influence of cloud top height on absorption in clouds and in the entire atmosphere is discussed. It is shown that the parameterization of the mean shortwave radiative fluxes, developed previously for low-level clouds, can also be used for water-droplet clouds with top height of up to 7 km.

Using the experimental data available on the microstructure of crystal clouds, a new model of the ice cloud microstructure is proposed. The model we propose allows for shapes, size, concentration, and orientation of the ice crystals. Using this microstructure model, we have calculated the phase scattering function, absorption efficiency, and the single scattering albedo of crystal clouds in the visible and infrared spectral regions. Calculations of the optical properties of an individual ice crystal are being done using the geometric optics approach with the account for the diffraction effects on the crystals having the size larger than the wavelength of incident radiation. The view of scattering phase function is shown to be mainly dependent upon different cloud microstructure parameters, provided that crystals of some shape dominate in the ensemble. The absorption efficiency and single scattering albedo of an ice cloud for the optical radiation are, to a high degree of accuracy, determined by the ratio of the ice content to the extinction coefficient of the cloud.

Backscattering of light by hexagonal ice crystals has been calculated within the framework of the ray-tracing method. It is shown that the backscattering properties of hexagonal ice crystals, including polarization, depend crucially on the particle orientations. A gigantic peak of backscattering is found at the tilt of the particles at the angle of 32.5 degrees. This peak has been explained by the peculiar 'effect of the corner reflector,' taking place in the solid hexagonal cylinders.

Analytical formulas are derived for integrals of phase function of large particles, namely for light fluxes scattered singly within an arbitrary angular range and mean scattering angle squared. The relations of the first kind are obtained via direct integration, by the scattering angle, of the Fresnel's reflectivities weighted with some angular function. The Fraunhofer's diffraction and geometrical optics parts are taken into account. As a result, the light flux is expressed as a sum of elementary functions. The formulas can be obviously converted to the known relations for the single-scattering albedo and mean cosine of the phase function for a particular case of the integration over full range from) to 180 degrees. The mean scattering angle squared is used, for example, by the small- angle diffusion approximation to compute light propagation. The corresponding formula is derived by comparing the solutions to the radiative transfer equation with the said approximation and with the small-angle one. The mean scattering angle squared is particularly shown to be inversely proportional to the effective size parameter squared of particles. The proportionality coefficient is found.

A problem on the illumination of a plane layer by a 'wide' light source and the recording of backscattered radiation by a 'narrow' - angle receiver is considered. An opaque obstacle can be inside the layer, i.e., optical properties of the medium are, in general, horizontal non-uniform. The light signal reflected from the medium with highly forward extended phase function (e.g., from a cloud) can be naturally partitioned to two components, the first arriving at the receiver from the medium in front of the target, the second - from the shadow region of the target. These components are calculated by the multicomponent approach to the radiative transfer equation, including the representation of the forward phase function as a sum of diffraction and geometrical optics terms. The computations are implemented for gamma size distribution of cloud drops. The first of the said components is analytically shown to depend weakly on microstructural parameters of the medium. The physical interpretation of such behavior of a signal, that can be regarded as a signal model for space lidar sounding, is given. The relation for the second component is also derived to show the regions of the medium providing higher sensitivity of the signal to the microstructural parameters as compared with the medium without target.

Within the framework of the small-angle approximation, a rigorous analytic solution to the problem of determining the instrumental function has been obtained for measurements of the scattering phase functions considering finite angular sizes of a radiation source and receiver. It has been shown that the instrumental function is described by an integral of a product of the Bessel functions. The instrumental function is expressed in terms of elementary functions. The effect of the instrumental function on the accuracy of measuring small-angle scattering-phase functions for different particle sizes is discussed.

Based on field data on spectral atmospheric transmission along the extended near-ground paths in an arid zone and in a region of West Siberia, excess continuous absorption of radiation in the 0.44-11.5 micrometers wavelength region has been revealed, which nonlinearly depends on the absolute air humidity. Its value, under assumption of quadratic dependence on absolute air humidity, is about 1000-1450 g ^-2cm⁵, far in excess of the continuous absorption by water vapor. The character of its spectral dependence suggests that it is related to the finely dispersed soot aerosol. The absorption coefficients obtained on the near-ground and slant paths are compared. The comparison made shows quite satisfactory agreement between them. The presence of the finely dispersed aerosol in the atmosphere is considered one of the important factors causing the anomalous absorption of optical radiation by clouds.

The kinetics equation is considered for the differential concentration of a single atmospheric aerosol component particles. For the size distribution function, the kinetics equation is obtained under assumption that the function describing an elementary size interval change due to gas-to- particle process doesn't depend on time. The terms in the right side of the equation are due to gas-to-particle conversion and presents the product of the particle growth rate and the particle size derivative of the differential concentration. Under mist the particles' growth rate is determined as the product of three factors: the supersaturation of condensing substance, the function describing particles' volume dependence on air relative humidity and the function of particles size, which is analogically to the growth law in the dry atmosphere. In case of multicomponent aerosol we use the kinetics equations system. The equations of system are related with each other due to coagulation process and redistribution of condensing gas impurities on al aerosol components. It is shown that polymodal approximation is the effective instrument to solve different tasks of multicomponent aerosol kinetics. The possibility to control and aerosol structure and physical- chemical composition is illustrated by help the simple kinetics model of water-soluble and soot aerosol at the stationary approximation. Coagulation process is considered by analogy with gas-to-particle conversion processes. Therefore, the growth rate of particle volume and size is presented as the sum of two terms. The second term allows to take into account coagulation process approximately for a wide range of particle size change. For soot, water-soluble particles, the particular cases of growth law are considered. To determine soot volume part in aerosol mixed particles the analytical method is suggested.

Most theoretical investigations into the problem of turbulent transport of pollutants consider the case of their transport by an air flow above an even underlying surface. However, in Russia, sources of industrial pollution are more often surrounded by forests. In the present paper, a mathematical model is suggested that describes the turbulent transport of aerosol pollutants under conditions of extremely rough underlying surface (forest). A single elevated source of atmospheric pollution is considered. In case of several sources of pollution, the principle of superposition can be applied.

The aerosol particle size depends on the air relative humidity. In the range of air relative humidity from 0.2 to 0.93, the equilibrium particle size is determined by the Kasten formula. This formula is an asymptotic approximation of the solution of the linear differential equation at t equals (infinity) . The first order differential equation describing the particle size variation dynamics establishes a new aerosol parameter, name the time constant.

Results of the statistical analysis of height distribution of the atmospheric aerosol in the boundary layer are presented. Data on the lidar sounding obtained in Tomsk (56 degree(s)N, 85 degree(s)E) were used as starting data. Vertical stratification of atmospheric aerosol is found following the modified method of clustering of arguments.

Experimental data on statistical properties of an aerosol content in the atmospheric surface layer collected by an in situ method with a nephelometer and ultrasonic meteorological stations are presented. Thus, obtained data are classified on the basis of the Monin-Obukhov similarity theory has been done. The analysis of asymmetry coefficient of the scattering phase function has shown, that the change of microphysical properties of aerosol happens with delay by approximately 6 hours after the establishment of stable thermal stratification. On the contrary the change of sign of stratification results in an immediate reset of microphysical parameters to the initial condition, i.e., without any delay.

The results of floodlight sounding of atmospheric layers with spatio-oriented nonspherical particles are presented in this paper. It is shown that components obeying the regularities of diffuse scattering and specular reflection occur in the scattered radiation as a result of interaction of the directional optical radiation with such a layer. Depending on observational conditions, the intensity of specularly reflected component might be several times higher than the intensity of radiation diffusely scattered in the same direction.

The results of complex experiments on smoke aerosol study are presented. The complex inverse problem has been solved for the data of light-scattering matrix measurements for a number of smokes. That have allowed to retrieve the volume particle's size distribution as well as real and imaginary parts of refractive index of particle matter. It was found that the majority of smokes, in particule's radii region r equals 0.05 - 2 mcm, have narrow single modal volume size distribution, which can be approximated by lognormal one. The connections among materials, which were burned, methods of burning particles sizes and their refractive index were displayed. For some smokes, the anomalous spectral dependences of the extinction coefficient and the degree of linear polarization were detected. The calculations by means of the harmonical oscillator model showed that this effect can be explained by the existence of an absorption band in this spectral region.

Results of remote sensing of the earth's upper atmosphere with the help of the astrophysical space station, Astron, obtained using a tangent sensing arrangement and the ultraviolet wavelength region (273, 280 nm), are presented. Profiles of the aerosol scattering parameters at altitudes 50-100 km in the equatorial zone and at the middle latitudes have been reconstructed. Vertical profiles of ozone concentration at altitudes 55-65 km have been estimated as well. According to the data obtained, thick aerosol layers were observed between 65 and 100 km and near 500 km. It is established that after the spacecraft launch (Space Shuttle), a long-lived and extended anthropogenic aerosol layer is formed at altitudes about 100 km. No significant influence is found of the spacecraft launch on the aerosol scattering characteristics at altitudes from 50 km and u to 85-90 km and on the ozone concentration between 55 and 65 (the characteristic scale of horizontal averaging in tangent sensing is about 10³km).

A two-stage procedure of detection of thermal, fire-type anomalies on the territory of the region form satellite date of AVHRR radiometer has been considered. At the first stage, the field of thermodynamic surface temperature is retrieved using non-linear, non-parametric regression equation, which is adapted to specific observation conditions using coincident meteoroligical data from the existing meteorological stations as well as data of AVHRR radiometer on NOAA satellite. At the second stage, on the basis of retrieved temperature field, an adaptive Bayes rule of detection of thermal anomalies is constructed, which is based on the principle of identification of the components of mixed distribution and approximation of conditional probability density functions by Johnson curves. An example of identification of thermal anomalies from satellite videodata for the territory of Tomsk region is presented.

The problem of forest fire detection from space using infrared channels of advanced very high resolution radiometer (AVHRR), under conditions of broken clouds, has been considered. Using numerical simulation technique, we studied the statistical characteristics of intensity of upward IR radiation, emitted by the fire and backing, including emission of surface, atmosphere, and clouds in wavelength intervals 3.55 - 3.93 and 10.3 - 11.3 micrometers . Gamma distribution is suggested for approximation of probability density of background power recorded by radiometer. Using the Meyman-Pearson test, we estimated the probabilities of detection of fires of different sizes. The obtained results illustrate the efficiency of the suggested approach.

The possibility of image improvement by increasing its resolution using operations of fragment selection, interpolation, point-spread function reconstruction, deconvolution and regularization is considered. First two operations broaden the spectrum of image spatial frequencies, and others remove image blurring and noise. The approach effectiveness is demonstrated on examples of processing the images for different parts of the earth surface, which were taken from the satellites NOAA and 'Resurs - MSU.' It has been shown that the resolution can increase in not less than 10 times.

In the present paper, some experimental results are given of investigations into the effect of the scattering medium comprising a smoke aerosol on imaging of low-light small- sized objects radiating light pulses. An optoelectronic system capable of recording single photons was used to record images. Its brief description is given. A measurement procedure and a date processing algorithm are also considered. It has been established that the laws of distribution of signal and background noise photocounts remain unchanged when the density of the scattering medium changes. Nonmonotonic character of image contrast variations attendant to the increase of the optical thickness of the medium is pointed out. The feasibility of estimating the information capacity of this imaging system is analyzed in case of photocount accumulation in real time.

The paper presents two algorithms of the Monte Carlo method for estimating the optical transfer function (OTF) of the atmosphere-underlying surface system. Some results of numerical calculations of the mean value of the frequency- contrast characteristics of the scattering coefficients of a random field are presented. The calculations are based on horizontally-inhomogeneous models of the stochastic atmosphere, built on the Palms fluxes. The values, on the average, increase when transferring from the determined model to a one-dimensional stochastic model and then to a 3- D stochastic model. The obtained values of the frequency- contrast characteristics (FCC) were used for the correction of the simulated 'space snapshots' of test objects.

Inverse optical problems are considered as a problem of point convergence from different convex sets characterizing the solution properties. If some functional is chosen as a measure of convergence, then any of its minimizing sequences determine the solution of an inverse problem. We consider in detail coordinate-by-coordinate descent to the functional minimum, which leads to projection methods of the inverse problem solution.

Knowledge of the state of the ionospheric radio channels is of great importance for both ionospere research and radio wave propagation predictions. Diagnostic of ionospheric radio channels is carried out by the analysis of ionograms. An efficient method of ionogram processing is proposed. It uses an artificial neural network (ANN) with the mean field theory updating scheme. Because of a complex character of ionospheric traces with quite a heavy background, a modified rotor model of Hopfield network is used. To speed up the convergence of the ANN evolution, a special initial ANN configuration is constructed in a vicinity of the global minimum of the ANN energy function. It is done by applying a special angular histograming within a sliding window, whose size is determined by the average local track curvature. Our model was tested on ionograms obtained on the chirp- ionosonde (ISTP, Irkutsk). Result analysis shows the efficiency of our approach and its prospects for the solution of the ionograms processing problems.

Propagation of partially coherent radiation through strongly absorbing media is studied in this paper. The equation for coherency function was used in the investigation. It was shown that the equation could be reduced to a system of ray equations, assuming a construction of an efficient numerical procedure for its solution. For parabolic distribution of the dielectric constant and an initial Gaussian distribution of the average radiation intensity the analytical solution for a field was obtained. Based on this, the influence of the refraction on inhomogeneous profiles of the refraction index, the absorptance on the statistical, and energy characteristics of radiation were investigated. The peculiarities of coherent and partially coherent radiation propagation through inhomogeneous media were found.

A physical phenomenon of wave propagation has certain logarithmic threshold of complexity above which the conventional description of wave process is inadequate. From this reason the real-place zeros of light wave are examined in the present paper. The probability of the real-plane zero occurrence is calculated by the numerical simulation of the light-wave propagation in an inhomogeneous medium. The functional relationship between the phase and the amplitude logarithm of the wave function near its real zero point has been found. This result takes the form of the dispersion relation, derived analytically and supported by numerical experiments.

We suggest hardware realization of the Newton iteration method in the problem of modal reconstruction and correction of angular segmented mirror aberrations by functionals of the extended source image. A special basis for the wave- front aberration function, which makes it possible to cut the problem dimension in half is proposed. We present results of numerical simulation for the six-segment mirror with account for measurement noises.

Identification aberration algorithm for the automatic phasing of an adaptive optical system with a segmented controllable mirror is proposed. Aberration information from the spatial frequencies of the intensity distribution in the image is defined. We consider in detail the case of a three- segmented mirror.

A numerical model of the wind-driven undulation of the sea surface is constructed in this paper. This model was used for studying optical properties of the sea surface by the Monte Carlo method. It is shown that simulation of the field of the sea surface elevations makes it possible to more precisely determine the optical properties of the swell with allowance for multiple reflection effects and radiation shading by surface elements.

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 have studied theoretically the problem on the resonance excitation of surface oscillation of the transparent liquid weakly viscous particles of arbitrary size under the modulated laser irradiation. The dependence of the droplet surface deformation amplitude on the radiation modulation frequency was determined for different values of the particle radius. The characteristics of induced oscillation of particles at their resonance excitation were investigated. The increase of the resonance characteristic width of surface oscillation was observed with the particle size decrease and with growth of liquid viscosity as well. The problem of light scattering on oscillating liquid particles was numerically studied. The greatest modulation of scattered light is shown to occur in the directions normal to the incident radiation, as well as in the direction of primary rainbow.

There are many laser and optical-navigation systems located at the world spacedromes, among which are laser range finders, optical refractometers, television systems of monitoring of the visible and infrared spectral range, systems of optical navigation and aiming and so on. These instruments are used in the information systems for solving the problems when launching space rockets. For precise operation of such optical systems, efficient information is needed on the effects of the real atmosphere on precise and energy characteristics of the used optical-electron devices.

Lidar technology and applications are well-established (Kirchbaumer et al. 1993). A backscatter lidar technology experiment was tested in space in 1994 (Winker et al. 1994). Scientists need global information on wind, clouds, and aerosol layers. On a space-borne platform, only a limited amount of power is available for a lidar system. Therefore, a compromise is necessary between the possibilities and the requirements.

In this paper we describe the algorithm of simulating and of scanning cw Doppler lidar operation in the boundary layer of the atmosphere. We show examples of simulation data, sine- wave fitting procedure of simulated data, examples of restoration of given profiles of mean velocity and dissipation rate of turbulent energy, as a result of processing the simulated data.

The accuracy of the autocorrelation function method, spectral function method, and maximum likelihood method, as a function of the parameters of the turbulent atmosphere, is studied and compared. The cases of the stable, unstable, and indifferent stratification are considered. The theoretical analysis of the Gaussian and non-Gaussian frequency fluctuations shows that the measurement accuracy of the Doppler shift depends strongly on the state of the turbulent atmosphere, the parameters of the Doppler Lidar and on the method used.

We investigate the speckle effect in atmosphere Lidar returns. Temporal developing speckle patterns in the receiver plane are simulated. The atmospheric model behind this simulation divides the atmosphere into small slices. The contribution from each slice to the field at a particular point in the receiver plane is a sum over a large number of contributions and can be replaced by a Gaussian distributed random number of appropriate variance.

LabVIEW (National Instruments) provides a powerful instrumentation system for simulations, including an excellent graphical presentation environment. Our Doppler Lidar simulation tool contains signal propagation and scattering in the atmosphere, a model of the heterodyne front end in the low SNR-regime and a processing unit for signal digitizing and frequency estimation. As a consequence of LabVIEW's programming language, G, this end-to-end simulator for Laser Doppler wind measurement can run on either a Windows PC, a Macintosh PowerPC or a SUN station.

The purpose of this paper is to present and summarize the activity of the Florence group, relevant to the effect of multiple scattering in the lidar technique of sounding clouds or fog.

We present here an approach to estimating the multiple scattering (MS) contribution into the lidar returns from clouds recorded from space that enables us to describe in more detail the return formation at the depth where first orders of scattering dominate. The estimates made enabled us to propose a method for correcting solutions of single scattering lidar equations for the MS contribution. We also describe here an algorithm of reconstructing the profiles of the cloud scattering coefficient and optical thickness, (tau) , under conditions of a priori uncertainties. The approach proposed is illustrated with the results on optical parameters of cirrus and stratiform clouds determined from return signals calculated by Monte Carlo method, as well as from return signals acquired with the American space-borne lidar during LITE.

Some results of experimental investigations of integrated water vapor and integrated cloud liquid water content obtained in different geographical regions and meteorological conditions are presented. Uncertainty of water vapor determination is about 2 kg/m². Radiometrically obtained mean liquid of stratocumulus compares favorably with empirical models based on airborne soundings. Observations of water vapor during thunderstorms are analyzed.

A new, fast algorithm of solving convolution equation with a nearly rectangular kernel is proposed. The algorithm was tested on incoherent scatter power profile data. The algorithm can be used for a wide range of practical problems, where there is a need for reversing the convolution of experimental data with nearly rectangular kernel and can be extended to kernels which are not rectangular.

During radio wave ionospheric soundings in the short-wave range, reflected signal distortions are mostly determined by the parameter (gamma) , a relative amplitude-frequency characteristic slope of the ionospheric slope of the ionospheric radio channel. This paper demonstrates the possibility of using this parameter to investigate the inhomogeneous ionospheric structure. In terms of the phase screen model, there is established the association of the radio channel amplitude-frequency characteristic slope with the properties of ionospheric irregularities. On the basis of the relations obtained, the experimental data is processed. Estimates are made of inhomogeneous ionospheric structure parameters.

This paper presents a technique for separation of a powerful coherent component and a weak noise-like component of a scattered signal. The method is based on the linear accumulation of signal samplings and the original method of determining the phrase of coherent parts. This technique was tested on processing the data from the ISTP IS radar, showing the possibility of effect part elimination from the signal, which is associated with reflection from mountain relief. The proposed technique can also be used in other problems, which need elimination of coherent interferences from the scattered signal.

The method of radio wave backscatter from small-scale fluctuations of the medium is extensively used to diagnose the atmosphere and ionosphere. In the statistical theory of scattering, the relation between correlation functions of the scattered signal and fluctuations of the medium was established and scrutinized; also, the single scattering approximation and an additional assumption of the smallness of the spatial radius of correlation are normally used in obtaining the radar equation of the problem. This paper analyzes the usual expression for a single scattered waveform, rather than its energy characteristics. We suggest a procedure, based on using a special Fourier spectrum of fluctuations and calculating the scattering amplitude at each spatial harmonic by a 3-D method of stationary phase (MSP) for obtaining the equation relating the scattered signal to spectral characteristics of the medium. Two equivalent representations are obtained for the signal scattered from spatial harmonics of fluctuations of the medium, and selective properties of the scattering process are considered. We have shown that it is possible to obtain a standard radar equation for a statistically quasi- homogeneous medium based on the derived representations.

We discussed here a possibility of determining characteristics of the wind field near the sea surface in the regions of a tropical cyclone based on the radiation- wind models available. The grounds for the discussion is data on three tropical cyclones in the Pacific ocean, acquired with the VHF-SSM/I radiometer from onboard the DMSP satellite. Before making analysis, we have processed the data collected and have given its interpretation from the standpoint of meteorology. The wind fields reconstructed are compared with independent data from storm warning services. It is shown that the use of the radiation-wind models and algorithms developed for standard meteorological conditions allow one to retrieve, with good accuracy, such important wind field characteristics, in the tropical cyclone region, as the dimensions of a pre-storm zone, wind field asymmetry, local maxima in the wind field, etc.

A new method has been suggested for reconstruction of raindrop size distribution and rain intensity from the normalized spectra of acoustic signals measured with a cw bistatic Doppler sodar. A data processing algorithm has been constructed and successively used for real sodar data processing, based on the analytical formulas derived in the Rayleigh approximation and with the use of the exact Mie formulas. The raindrop size spectra were reconstructed from the individual power spectra of signals recorded every 20 s and from the signal power spectra averaged of 2-, 3-, %-, and 25-min periods. This has allowed us to track the dynamics of the raindrop size distribution. The presence of the second maximum of the number density of large raindrops was established, whose position shifted with time from 0.3 to 1 mm. Our study has shown that the large raindrops were grouped in ensembles and the second maximum of the raindrop size distribution was observed only periodically. The obtained results demonstrate that high- frequency cw bistatic sodars are very promising for measurements of rain.

We present the dynamics of stratospheric aerosol characteristics after the Mt. Pinatubo eruption. Measurements were carried out with a lidar, which has been operating at 532 and 1064 nm wavelengths. An approach to the processing of two-wavelength polarization sounding data is presented. Altitude-temporal dependence contours of the aerosol backscatter ratio, the ratio of aerosol backscatter coefficients at two wavelengths, and the aerosol linear depolarization ratios are given. Possible temporal transformations of the stratospheric aerosol microstructure characteristics that cause the changes in optical parameters are discussed.

Several physical factors that govern the light scattering scenario in optically anisotropic media are discussed and the degree to which they may affect the date of laser sounding of crystal clouds is assessed. Among the peculiarities of light propagation and scattering in such media there are: 1) possible changes in the state of polarization of a sounding beam; 2) the transformations of the polarization state and extinction of sounding radiation may depend on the direction of sounding; 3) the data of laser sounding regarding the backscatter and lidar depolarization may be ambiguous. The matter is that in an anisotropic medium these properties of the backscattered radiation depend on the polarization state of a sounding beam and on the orientation of the lidar. As the calculated and experimental data presented in this paper show, the change of the sounding beam polarization state during the propagation in cirrus clouds may be neglected in the majority of practical cases. At the same time, the dependence of the radiation extinction on the direction of sounding, as well as the ambiguity in sounding data mentioned above should certainly be taken into account.

Lidars are widely used for sensing of sea water turbidity and bottom depth. Our Makrel'-2 lidar has been used since the 1980s for water monitoring and searching for schools of fish over the Norwegian, Barents, and North seas. In the present paper, we discuss the results obtained with our lidar, placed onboard the Optik-E Antonov-30 aircraft- laboratory during our flight over Lake Baikal on November 2, 1996. Some results of lidar data processing are presented, which demonstrate the salient features of lidar return signals and the possibilities for lidar signal processing. The extinction index of the purest water found in the northern part of Lake Baikal was 0.12_MIN^PLU0.01 m^- (averaged over 600 pulses). In the region near the mouth of the River Selenga, the extinction index changed from 0.14 to 0.6 m^-. The minimum and maximum bottom depths recorded with our lidar are estimated. We detected bottom depths as great as 40 m when the aircraft flew near Bol'shoi Ushkanii Island.

Integral methods of lidar determination of atmospheric optical parameters are discussed in this paper. The integral solutions of lidar equation commonly in use for sounding of inhomogeneous atmosphere suffer from the fact of a priori assumed optical properties of the medium. It has necessitated the development of new multiposition techniques of lidar sounding. K-position lidar techniques are based on sounding of investigated atmospheric volume from different points in space, along the paths, making up a closed polygon in intersection. Unlike traditional methods, new methods give a posteriori possibility of the estimation of the results' reliability. The simulations of the statistical and systematic errors were performed for multiposition schemes of lidar sounding. New approaches appear as a result of the errors in calculations, to be effective for a variety of typical atmospheric scenarios. The additional effectiveness of the method is connected with combining of traditional and multiposition lidar sounding schemes.

This paper is devoted to the mathematical simulation of a ground-based lidar system, which is designed for remote sensing of atmosphere and its optical parameter range profiles reconstruction, under strong background radiation conditions. In particular, from these parameters, it is possible to obtain information about number concentration of aerosol particles in the atmosphere, water content in clouds and pollutants.

We propose a new optical arrangement of the double grating monochromator (DGRM), intended for use in a pure rotational Raman-lidar. The main idea of the construction proposed is in the use of optical monofibers, to couple two chambers of the DGRM. The coupling with optical monofibers enables isolation of two pairs of spectral portions in the S and O branches of the pure rotational Raman spectra (PRRS) of nitrogen and oxygen symmetric relative to the line of exciting radiation. The use of monofibers provides for optically summing the symmetric portions of the PRRS at the exit of the second monochromator, thus increasing the power of PRRS collected for further temperature retrieval. It is important that this approach provides for better than 10⁷ suppression of the spectral line, due to unshifted Mie+Rayleigh scattering. As calculations and laboratory experiments show the end-to-end transmission of the DGRM, with the account of optical summing mentioned, can compare with the transmission of the interference filters available. At the same time, the DGRM provides better spectral purity of the RRS portions isolated, which is a crucial point of the Raman-lidar temperature measurements. Temperature profiles of the atmosphere acquired with the combined Raman- lidar of the Institute for Tropospheric Research in Leipzig, Germany, equipped with the DGRM proposed, showed a good agreement with the profiles measured with a radiosonge.

Different lidar receiving objects (three types of refractors, two reflectors, three refractor-reflectors, and two multicomponent objectives) have been analyzed using some generalized performance criteria. The method proposed for making a comparison based on the diagram, involving the efficiency factor and overall dimensions of the objective, enables one to choose an optimal objective according to the proposed factor of the relative efficiency or the minimal longitudinal dimension (at the same light diameter). From its point of view, in the order of increasing longitudinal dimension, the Mangene objective, the Fresnel lens, the multicomponent objective, and the Cassegrain objective are most compact, respectively. However, the Mangene objective has the smallest factor of relative efficiency.

An exact analytic description of the lidar geometric factor, in the form of an integral of a product of the Bessel functions, has been analyzed for separated source and receiver.

Climatic analysis of the vertical structure of stratospheric ozone concentration and its statistical characteristics (average values, standard deviations, autocorrelation functions, eigenvectors, and egenvalues) over Western Siberia has been made based on the data of lidar sensing in Tomsk (56 degree(s)N, 85 degree(s)E) in 1995-97. Regional peculiarities in the vertical ozone distribution, its variability, and behavior of the correlation function caused by specific features in the stratospheric circulation and primarily in its meridional component over Western Siberia have been established. Seasonal peculiarities in the behavior of three eigenvectors of the ozone covariance matrix have been established and their contribution to the total variance (being equal to about 85-88%) has been estimated.

Results of ozone sensing with a twilight spectrophotometer and an ozone lidar are discussed in the present report. A brief description of the spectrophotometer is given. A procedure for observation and a method for reconstruction of vertical ozone profiles is described.

Total ozone (TO) content measurements have been performed by different organizations on a regular basis at Murmansk ((phi) equals68.97⁰N, (lambda) equals33.05⁰E; (Phi) equals64.5⁰N, (Lambda) equalsaa5.2⁰E). All the data of ozone observations from 1971 through 1997 are collected as a database in the Geophysical Observatory Loparskaya. An initial analysis of collected data was implemented and it was noted that the TO over Murmansk during the last 27 years showed the decreasing of the one. A seasonal behavior and other characteristics of TO were obtained.

Zeeman atomic absorption mercury analyzers are widely used in ecological monitoring, geochemistry, and analytics. In this paper, we describe UV analyzer with Zeeman background correction RGA-11 and its modified version, which is intended to measure enhanced ozone concentrations in the atmosphere.

Results of regular long-term spectroscopic measurements of carbon dioxide and water vapor in the atmosphere over the Issyk Kul station (42⁰ 37' N, 79⁰ 59' E, 1650 m above sea level) from 1980 through 1997 are discussed. The technique of spectroscopic measurement used is based on recording spectra of solar radiation passed through the atmosphere. Recorded were the spectrum portions within the CO₂4v₂ + v₃ absorption band at 2.06(mu) . Analysis of the spectrograms recorded within this interval, including the wings of this absorption band, enabled us to reconstruct both the carbon dioxide and water vapor content in the atmosphere.

We present here some measurement results on the atmospheric methane column density, which were obtained in Zvenigorod, in September 1997. The measurements have been carried out in parallel, using several variants of the spectroscopic method and instrumentation. Thus, obtained results showed that three different modifications of the method and measurement instrument that are normally used on long-term observations in different observation sites yield, when operated in one site, the data that agrees quite well.

Since 1990, regular measurements of columnar abundance and vertical distribution of NO₂ are carried out at Zvenigorod Scientific Station (50 degree(s)N, 38 degree(s)E) of the Oboukhov Institute of Atmospheric Physics with the use of visible, zenith viewing, grating spectrometer scanning in the wavelength range 435-450 nm. Measurements are done during morning and evening twilight at solar zenith angles 84 degree(s) - 96 degree(s). The method of NO₂ derivation is based on analysis of NO₂ differential absorption taking into account ozone absorption, single molecular and aerosol scattering and the Ring effect. Vertical NO₂ distribution is retrieved as a solution of reverse mathematical problem using the Chahine method. The kernel in the problem is computed taking into account photochemical processes. A NO₂ vertical profile is represented by ten 5-km thick layers and a thin surface layer. Counting the surface layer as an additional layer is necessary for correct NO₂ determination in conditions of the lower troposphere contaminated by nitrogen oxides. Results of eight years of NO₂ measurements at Zvenigorod Station are presented. The NO₂ annual variations in the stratosphere and the troposphere are analyzed; effects of interannual NO₂ variability are considered as well. Also analyzed are the NO₂ decrease in 1992 after the Mt. Pinatubo eruption and the following gradual recovery of the NO₂ layer. Other NO₂ anomalies are considered as well.

A new characteristic of the sea surface radiance spectrum is suggested as a parameter for the optical remote sensing. It gives the possibility of efficient estimation of light absorbing and light scattering admixture concentrations in sea-water being practically invariant to the affection of the atmosphere. This parameter is the gradient of the sea spectral radiance coefficient distribution within the band 490-510 nm. The investigation of this gradient dependence upon the type of sea water in the open ocean, as well as in the Mediterranean, Black and Baltic Seas was carried out. The results are given, showing the high informativity of the suggested parameter. It should be stressed that the atmospheric light scattering doesn't contribute much to this parameter by ocean remote sensing through the atmosphere. That's why the spectral gradient of sea- atmosphere radiance coefficient at about 500 nm can be used for sea monitoring practically without atmospheric correction.

The results of light absorption spectra measurements on different depths of Lake Baikal are presented here. The empirical link equation between concentration of organic carbon in Baikal water and parameter describing absorption spectra are obtained. The equation allows evaluating organ substance contents in the water medium by results of optical observation.

The isoline maps were developed on the basis of database on radio meteorological parameters of group atmosphere, based on the values of main meteoelements up to 3000 m above the level of 146 stations on the territory of the former USSR. The set comprises up to 20 maps, characterizing spatial distribution of average and average square deviations of ground values of refractivity, vertical gradient, main meteoelements in different times of the day (morning, noon, evening and night) of the middle months in four seasons of the year. It also includes 4 maps of average monthly values of the said parameters.

This paper presents new results obtained by the authors in the development of technologies for monitoring the atmospheric boundary layer anomalies, caused by the microgeochemical conditions or industrial pollution emissions.