The history of science in Siberia has begun long before the establishment of the Siberian Branch of the national Academy f Sciences. The following fact confirmed this statement: 1) the foundation ofthe Tomsk Imperial University in 1878 and after this the foundation of the Tomsk Technological Institute in 1896; 2) the foundation in 1922 in Tomsk of the Institute of Applied Physics of the Siberian Technological Institute ( as a social service), which was reorganized in 1928 into the Siberian Physico-Technical Institute (SPTI) as a result of enormous work of physicists, and first of all, professor Vladimir Dmitrievich Kuznetsov, the founder of SPTI and its permanent director from 1928 to 1933 and then from 1938 to 1960. Right until the beginning of establishment of the Siberian Branch of the USSR Academy of Sciences in 1957 the city of Tomsk, undoubtedly, was the first in Siberia in the progress of science, but, nevertheless, a decision was made to establish the science centers of the Siberian Branch of the USSR Academy of Sciences in Novosibirsk, Irkutsk and Yakutsk based on the West-Siberian, East-Siberian and the Yakut Branches of the USSR Academy of Sciences as well as on a blank pace in Krasnoyarsk and not in Tomsk through the fault ofthe administration of the Tomsk region of those days.

The molecular structure and properties of (H₂O...HF)_n, n equals 1 - 3, complexes were studied. Structural parameters were found from HF/6-31G* ab initio geometry optimization. Vibrational frequencies were calculated from Newton-Raphson/3-21G ab initio optimization routine of second derivatives of the potential. Analysis of spectral features of complexes such as vibrational band shift has been done.

The medium where the electromagnetic field propagates, in relation to the parameters characterizing the electric field, is found to form a linear dynamic system. The magnetic field parameters are related in a similar way. Based on this statement the Maxwell macroscopic equations are derived from the microscopic equations. The relative dielectric constant is a positive real function of complex variable and can be represented by the fractional-rational function. The paper describes the mathematical grounds of the substance polarization Lorentz model. Besides its correction is given taking account of the magnetic field action. A consideration of the relative dielectric constant in space of a complex variable enables, us, along with the Kramers-Kronig formula, to obtain a series of new relationships for its real and imaginary parts. We derived the expression of the coefficient of transfer of a plane wave through the propagation medium. The requirements are given to which the transfer coefficient must satisfy when the signal transfer is not distorted.

Measurements of direct and diffuse solar radiation in cloudless atmosphere were conducted in 1984 and 1996 - 1998 in South-Eastern Kazakhstan (not far from Almaty city) during the period July - October. The day sky spectrophotometer, operating in 8 spectral bands within the interval 0.42 - 22.2 microns, was used. Aerosol phase function was inverted from diffuse radiance in the solar almucantar using proposed earlier adjustment method. Aerosol optical depth was calculated by long Bouguer method for solar zenith angles 30 degree(s) - 80 degree(s) (both a.m. and p.m.) under condition of stability of atmospheric optical transparency during 1 and more hours.

In the paper we suggest an empirical model for calculation of aerosol extinction of 0.4 - 12 micrometers wavelength radiation in the near-ground atmospheric layer from measured values of extinction coefficient at two visible wavelengths. The performance of the model under different meteorological conditions is tested. This model is shown to satisfactorily describe the experimental and calculated models of aerosol extinction for different climatic zones and most optical weather types (hazes, fog hazes, haze with drizzle, haze with incessant rain, haze with snow or graupel, ice fog).

This paper deals with the problem of interaction between the optical and electrical parameters of atmosphere. At present the interaction not investigated experimental enough. The results of several series of experiments are presented. The experiments in the artificial media camera; the experiments with the nephelometery installation; the experiments on the measurement of spectral transparency of natural atmosphere by the base method is considered as well. The experimental results allowed us to note the existence of the electro optic ratio. The special conditions for observing the above ratio are discussed.

This paper is devoted to the analysis of variability of thermo- and hygrooptical characteristics of atmospheric aerosol particles obtained at artificial moistening and heating of aerosol sample. The tendency of decreasing the parameter of condensation activity during spring has been revealed. The relation between hygro- and thermooptical parameters are considered. The estimates of condensation activity of different aerosol fractions have been performed.

The night-time seeing measurements obtained with the ESO Differential Image Motion Monitor at Mt. Maidanak from August 1996, up to June 1999 are presented. This instrument was also used for seeing estimation at La Silla and Paranal Observatories in Chile in 1988 - 1996. The median value of seeing--(beta) _FWHM (the full width at half maximum of a long-exposure stellar image at zenith at (lambda) equals 500 nm) for the entire period of observations is 0.69 arcsec. For the La Silla and Paranal Observatories, this parameter is 0.87 and 0.66 arcsec, respectively.

The results of measurements of concentration of some aerosol-producing gases in the near-ground layer of the atmosphere are considered.

Correlation between total ozone content and scattered UV fluxes (A and B portions) measured in Tomsk (56.6N, 85E) during 1994 - 1998 has been investigated. It was shown that for the data corresponding to cloudless days the regression curve may be satisfactorily described both by exponential and linear dependence. With the cloudy days included the correlation decreases. There is no correlation between UV-A and UV-B fluxes when taking into account the observations at any cloudiness.

Data of in situ observations obtained in Zarechnyi Polygon of the Institute of Atmospheric Optics near Tomsk in the morning on October 9 1996, are analyzed. Ultrasound acoustic meteorological station was capable of recording with a frequency of 2 Hz three components of the wind velocity and temperature of the air, and a two-angle nephelometer of an open type measured the coefficients of scattering at angles of 45 degree(s) and 165 degree(s). Measurements have been carried out continuously for a long time at a sampling frequency of 2 Hz. Devices were mounted on the mast of 5 m height. When stratification was temperature stable, the quasi-periodic vibrations of meteorological parameters and parameters of aerosol scattering was temperature stable, the quasi- periodic vibrations of meteorological parameters and parameters of aerosol scattering were observed with a period of 25 minutes. The oscillations of the transformation coefficient of scattering phase function as well as of temperature were particularly pronounced. The view of time realizations pointed to the presence in the atmosphere of the known as buoyancy waves or gravity waves. The spectra of fluctuations of parameters were calculated. It is noted that spectra of speed, temperature and aerosol concentration, calculated from 17 minute intervals, in the low-frequency region of the inertial interval had greater slope in frequency region from 0.03 Hz to 0.2...0.3 Hz than the slope of the Kolmogorov spectrum (the -5/3 law). Simultaneously, analogous spectrum for vertical component of the wind velocity had the slope close to the Kolmogorov spectrum in the frequency range from 0.03 Hz to 1 Hz.

A rate of the ozone generation within the ground air layer depending on the solar radiation intensity is considered in the paper. The radiation consumption for formation of a unit of the ozone concentration is shown to range from 15 to 120 W/m² for 1 mkg/m³ and to vary in different seasons. It is greater in cold seasons when the ozone concentration is minimum and less in warm seasons with maximum ozone concentration. This reflects a peculiarity of the atmospheric ozone generation which starts from photolysis of the ozone available in the atmosphere. Empirical relations are obtained connecting the ozone concentration with total solar radiation.

We have experimentally studied the transformation of polarization properties of light scattered from particles oriented in an external constant electric field. A mathematical model of the phenomena observed in presented. It was established in this study that by measuring the behavior of polarization properties of backscattered radiation as a function of the electric field strength can enable one to estimate polarizability of particles and the form of the optical polarizability tensor.

Some problems, connected with the development of ground- based adaptive telescope, particularly, with equipping it with an additional optical system for laser guide star formation, are treated in the paper. The point of the work is determination of the type of the laser guide star being formed. Here, the calculated results are presented for scheme for laser guide star formation, when arbitrary magnitudes of the correlation between random angular displacements of the image of the scattering volume stipulated by the laser beam fluctuations over direct and back paths can be obtained. Expressions for the monostatic and bistatic schemes are obtained as limiting cases.

The algorithms of reconstruction of singular phase from the measurements of wave front slopes by Hartmann sensor, shear interferometer, and from the interference measurements of Knox-Thompson are proposed. Based on the hydrodynamic approach to description of the wave front spatial dynamics we have developed the algorithms which make it possible the singular phase of an optical speckle field to be reconstructed with the use of analytic representation of the phase in terms of its partial derivatives with the allowance for the vortex nature of the phase gradient vector field.

The probability-density function of the log-amplitude derivative was represented as regular part of Laurent series in a neighborhood of the point at infinity and then it was established that real-plane zeros exist only if asymptotic behavior of the probability-density function at infinity is inversely related to cube of the random variable. Therewith the density of points, where the light wave has zeros of any order, is determined by the coefficient with the index minus three of Laurent series for the probability-density function of the log-amplitude derivative. This result is reduced to known particular cases.

The correction of low-order aberrations is important in many adaptive optics applications. Modal cylindrical adaptive lenses can be used to correct several low order aberrations. Furthermore, the same technology can be used for creating arrays of controllable lenses. The most significant feature of these cylindrical lenses is a modal control system based on nematic liquid crystals. Modal control allows the precise control of the spatial phase distribution in order to achieve an aberration-free lens. This has been investigated both by computer simulation and experiment. We found that the introduction of a 180-degree phase shift between the second or higher order harmonics and no phase shift between the first harmonic components of the control voltages improves the optical performance of the device. These extra harmonics eliminate the strong dependence of the liquid crystal orientation on the impedance of the device. This is especially important for devices with small apertures. It also was found that modal cylindrical lens controlled by two-harmonic voltages can produce a slit-like beam whose transverse structure has the shape of a pulse which remains unchanged over a long range in the direction of propagation. We investigated a device with two-crossed 1D control electrodes and produced a lens with controllable focus and astigmatism.

Clearing of water aerosol by laser beam vaporization of particles is investigated and in the condensation trail behind aircraft. Physical parameters are calculated for the condensation trail behind subsonic and supersonic. Russian and American aircraft in cruise. Solutions are derived for the intensity of laser radiation, moisture (ice content) and optical thickness of the aerosol in the flow, which is parallel to the beam path. These physical values are described as a function of time and coordinate at the distances of significant medium clearing and radiation extinction.

We analyze here the influence of multi-mode excitation of stimulated light scattering (SLS) in the spherical particle on the angular intensity distribution in the far-field zone. It is shown that at multi-mode excitation of SLS the scattering diagram becomes asymmetric, unlike the case, when process is realized on single resonant mode of a particle. Degree of its asymmetry significantly depends on combinations of modes excited in the particle that brings either to a significant increase of the intensity of backscattered wave, or to its weakening in the given direction. The comparison with angular intensity distribution at elastic scattering is made.

Spherical dielectric microdroplets are known to be high- quality optical microcavities due to the existence of the quasinormal electromagnetic eigenmodes, usually referred to as morphology-dependent resonances (MDR's). These modes are the subject of considerable interest owing to their significant influence on such optical nonlinear scattering effects, as SRS, SBS, lasing. The resonant properties of a microcavity strongly depend on its shape. It was experimentally established that the distortions of droplet shape cause extra-leakage of MDR's-photons through droplet surface bulges, and hence, the spoiling of its Q-factor. The shape deformation can be simply caused by thermal fluctuations of liquid, or induced by a laser pulse due to ponderomotive effect, and have been observed in several experiments. The main purpose of the paper is theoretical investigation of the ponderomotive deformations of spherical droplets and their influence on radiative energy balance of MDR's. The task is considered on the basis of first-order perturbation approach to the boundary problem of oscillations of dielectric sphere in the electromagnetic field. The numerical simulations have confirmed experimentally observed fact that when the train of picosecond laser pulses is acting on the droplet the maximal surface displacement occur in the region of the so-called Descartes ring on the droplet shadow hemisphere. The radiative energy extra-losses in this region are caused by surface bulge, are proportional to its amplitude and lead to a decrease of the cavity Q-factor.

Radiation propagating through inhomogeneously absorbing media is investigated within of the geometric optics approach. On the basis of the equation obtained for a real ray trajectory, numerical analysis of propagation features is carried out for various symmetrical distributions of complex dielectric constant such as parabolic, Gaussian and power low distribution. On the basis of the numerical simulations the validity of the solutions constructed on real geometric rays is determined for a propagation problem of coherent and partially coherent radiation. It is shown that the solutions of the propagation problem within the geometric optics limit approach the exact solutions for partially coherent radiation faster than for the coherent one. Recognizing that the equation for the real ray trajectory is not the equation of the second order, we show that two initial conditions do not suffice the problem, namely index point and initial slope angle for the unique definition of the real ray trajectory. On the basis of the analytical solution obtained for the case of parabolic distribution of dielectric constant it was proved analytically that the ray trajectory in highly absorbing inhomogeneous media depends not only on the complex dielectric constant distribution, but also on the wave phase front distribution.

Propagation of optical radiation through media with complex dielectric constant is studied in this paper. The rigorous solution of this problems taking into account for curvature of ray trajectories caused by the inhomogeneous absorption is obtained on the basis of the ray-tracing technique. For a parabolic distribution of dielectric constant the analytical solution for a field is obtained. For this and other distributions of the complex dielectric constant such as Gaussian and power-low distribution the comparison is made for exact solutions and solutions neglecting the refraction caused by inhomogeneities of the imaginary component of the complex dielectric constant. It has been found that in the media where the imaginary component of the dielectric constant is comparable to or larger than the real component the effect of the curvature of the ray trajectories due to the inhomogeneity of the imaginary component is essential or dominate, respectively. The validity of solutions neglecting the refraction caused by inhomogeneous absorption is investigated.

An approach to the deconvolution of images of the Earth's underlying surface considering the distorting effect of the atmosphere is considered. The peculiarity of this approach is that the point spread function (PSF) used in the linear model of image restoration is unknown and should be estimated a priori. To this end the same image is used and information that the observable scene comprises objects with contrast brightness gradients. The Gumbel distribution of extremal values is taken as a stochastic model of image fragments with high gradients. For the alternative the family of the Johnson curves has been chosen. The Bayes decision rule based on these distributions identifies the external gradients. The brightness variations of a blurred image fragment along the gradients serve as a material for the PSF restoration. The image itself is restored with the use of a standard approach. An example is given to illustrate the PSF and blurred image restoration.

A two-stage procedure for correcting and restoring images of the Earth's underlying surface, recorded by AVHRR instruments placed onboard the NOAA satellites, is considered for some situations observed in the fall and spring. At the first stage (data correction), a method of histogram transformation is used to eliminate the effect of semi-transparent cloudiness. At the second stage (reconstruction), an approach based on the data reconstruction with the help of nonparametric regression dependences is used to eliminate shadowing effect of clouds. Some examples of correcting and restoring real images recorded with the AVHRR instrument are given.

Experimental results on forest combustibles (FC) burning are treated in the paper. The relations V equals V₀exp(-W²/W₀²) are proposed to describe the dependence of the burning front movement velocity on the humidity W (V₀ equals 3 mm/s is the velocity of the burning front movement for dry FC). Maximum radiation temperature of the condensed phase burning within the range of the 3 to 12 micrometers , reconstructed by the blackbody radiation law at the radiation coefficient (epsilon) of 1, is 800 - 900 K for dry needles of pine and cedar. The higher is humidity, the lower is the maximum radiation temperature.

Digital classifications of RESURS MSY-E data of forest Tomsk region were used. One scene acquired on 22 October 1992 was selected for classification. A supervised approach was used to generate training signatures for input to ERDAS classification. The classes (forest predominate composition) for classification were: (1) 80% cedar (pinus sibirica) + 20% spruce (picea); (2) 80 - 100% cedar without spruce; (3) moorland; (4) recent wood-cutting area; (5) old wood-cutting area; (6) 90 - 100% pine. Parametric and non-parametric decision rule were used. The GIS-compatible classifications provided a comprehensive view and evaluation of the results. Comparison of the results of classification with the forest management inventory data shows a satisfactory agreement.

We present some results of laboratory experiments on the image transfer of small-size objects emitting a radiation in a pulsed mode. The experiments involved viewing such objects through a dispersion layer in the near-IR range. A four-tie mira has been used as a test-object. The spatiotemporal statistics of photocounts, signal-to-noise ratio, and the average image contrast were analyzed in the image plane of the optical imaging system used. Dependences of these parameters on the optical density of a scattering medium are found. The feasibility of recognizing the objects equivalent to the above mentioned mira is estimated for the maximum values of the medium optical thickness realized in the optical experiments conducted.

This paper represents development of techniques for classification of forest regions using radar images. SIR- C/L-SAR data were used. The application of textural features and artificial neural networks was considered.

Intensive exploitation of Siberian forest resources requires to increase the level of their protection. In Russia, forests annually disturbed by fire make up about 6% of the total forest area, whereas they account for hundredth or even thousandth of per cent in the West European countries and Canada. Devastating forest fires associated with long draughts have become very common over recent decades in some parts of Siberia and the Russian Far East. Fires burning under these conditions disturb hundreds of thousands hectares of forest lands, and their detrimental effects, including economic damage, are hard to overestimate. This hard situation is attributed to that fire protection is far behind forest use. Another reason is the lack of well-developed scientific approaches to the problem. Current forest fire monitoring technologies have many weaknesses. Methods of fire danger rating and prediction and also techniques of forest fire damage appraisal need to be improved.

In this article the evaluation of correlation relation between subsequent frames of dynamic images of aerosol plumes and synthesized dynamic images construction is discussed. It was established, that such a procedure reduces the common level of noise of dynamic image, it is a method of compressing of information. Furthermore, the statistical accumulation of information on the object for the given period of time is happening as a result of toting initial sequences of frames.

In this paper, results of experimental researches of influence of turbulence on the laser beam image at reflection from a mirror are presented. The study was carried out with a beam focused on a reflector for correlated (monostatic) and uncorrelated (bistatic) paths under conditions of strong fluctuations of intensity. Distributions of the intensity were recorded in the image plane of a reflector and were analyzed. The distribution of intensity is shown to be the two-scale, having wide basis (turbulent scale) and narrow peak (coherent scale) under the certain conditions at the correlated path. The scales of the object image have been determined depending on conditions of propagation and of a diameter of the receiving objective.

We present some results of experimental investigation into the formation of plasma formations at optical breakdown of air initiated with high-power radiation of a CO₂ laser. Based on spectral and temporal characteristics as well as on photographic images of the plasma cells recorded we have shown that the mode of plasma cell evolution changes depending on the power density of incident radiation that varied from 10⁶ W/cm² to 5(DOT)10⁹ W/cm². At the power density exceeding the breakdown threshold by two orders of magnitude there occurs the mode of the plasma cell evolution different than the mode of light-induced detonation wave resulting in the changes in the spectral and temporal characteristics of the plasma cells as well as in their shape.

In this paper the theoretical approach to the investigation of the measurement accuracy of the true radial velocity in the turbulent atmosphere is proposed. This approach takes into account the non-Gaussian statistics effect of the Doppler lidar signal and the spatial averaging effect. The cases of the maximum likelihood method, the autocorrelation function method, and the spectral function method are considered. It is shown that the measurement accuracy of the true radial velocity measurement depends on the signal statistics, i.e., the parameters of the atmospheric turbulence and a Doppler lidar used. The measurement error variance of the true radial velocity is the sum of the Gaussian and the non-Gaussian components. It follows from the comparative analysis of the measurement accuracy of the true and average radial velocities that measurement error variances have different values. The Gaussian components of the measurement error variances of the true and average radial velocities have the same from. The non-Gaussian components of the measurement error variances have the different values. The non-Gaussian component is not averaged with increasing the scattering volume length; it tends to a constant value.

The information system HOTGAS 2.0 for calculation of rovibrational spectral line parameters (centers, intensities, half-widths, energies of low states) of CO, CO₂ and H₂O in 0 - 10000 cm^-1 spectral range and in 200 - 3000 K temperature range is described. The information system HOTGAS 2.0 developed for Windows 95,98,NT has a friendly user interface with textual and graphical information performance, which allows for using graphics and tables in other Windows applications, such as Word, Excel, etc. The HOTGAS 2.0 makes calculations of the absorption coefficient for single or mixed gases available.

The experience on the first backscatter lidar operating in space (LITE, USA, 1994; BALKAN, Russia, 1995 - 1997; ALISSA, Russia-France, 1996 - present time) is analyzed to provide a basis for guiding the development of new orbital lidars. Considering the status of development of laser sensing methods harnessing elastic scattering and needs for obtaining information on global distributions of atmospheric aerosols and cloudiness in real time, approaches to the conversion of lidars of this class from the testing regime of operation to the monitoring one are discussed. Within the framework of this approach the design features of lidar intended for accommodation on small space stations most suitable for monitoring are investigated. For such a lidar a deploying segmented mirror has been suggested which does not provide a narrow directional pattern due to the conditions of its transport to the orbit. Multiple scattering by atmospheric aerosols, which is responsible for principal background noise component of lidar return signals, has been investigated for lidars with large field-of-view angles. It is demonstrated that the multiple scattering background reaches 30% and more for a field-of-view angle of 20 mrad even under background conditions. The possibilities for consideration of this background contribution are discussed. Spaceborne lidar sensing methods, which have been developed insufficiently, necessitate the use and development of universal lidars that envisage the attention of the crew, that is, lidars for manned spacecrafts and space stations. The universal spaceborne lidar BALKAN-E, intended for testing of the methodology of ozone and aerosol sensing based on the differential absorption and scattering of laser radiation, is described. Similar lidars placed on stations with other scientific instruments will optimize a set of means for an integrated study of the Earth owing to mutually complementary measurements.

An equation for a multiply scattered lidar return from sea water is considered. The multiply scattered radiation is taken into account in the small-angle approximation, and only single scattering is considered at large angles. A relationship between the components of multiply and single scattered radiation is numerically studied depending on the receiver field-of-view angle at various optical depths of a water layer. A new representation of lidar return is suggested. It is based on the expression for a lidar return assuming unbounded field-of-view angle of the retriever. This approach allows us to consider multiple scattering as a useful signal component in solving inverse problems.

In the present report, results of Monte-Carlo simulation of the spatiotemporal structure of multiply scattered components of lidar return signals are analyzed for monostatic sensing geometry. It is shown that the instantaneous brightness body of multiply scattered radiation may have significant volume and extension in directions toward the receiver, inconsistent with that of forming the singly scattered signal component. Factors showing largest effect on spatial and brightness characteristics of this volume source are established.

Within the frame of the program on ecological monitoring of air masses, researchers of the Institute of Physics have performed a series of experiments on multi-frequency atmospheric laser sounding over the industrial region of Soligorsk City, Belarus. We obtained extinction, scattering, backscatter coefficients, and lidar ratio over the wavelength range of 0.38 to 1.06 mkm. There was observed a number of peculiarities in the said spectral dependencies differing from those for quite a pure atmosphere. Specifically, backscatter and lidar ratio spectra could have a maximum within the studied spectral range or increase monotonically towards the infrared edge of the spectral range. As for atmospheric sounding at sites rather distant from high-power polluting sources, one observes usually decreasing corresponding spectral dependencies with wavelength increasing. The same behavior is given by well- known optical models of atmospheric aerosols, e.g. by the WMO model.

We present some results of investigation of vertical profiles of the aerosol scattering coefficient based on the statistical analysis of data acquired during the whole day round lidar observations of the atmosphere in a spring- summer season. We have arranged several sub-arrays of the data compiled as referred to different types of air masses, seasons and time of day. From analysis of thus grouped data sub-arrays we have revealed certain distinctions in the behavior of inter-level correlation matrices characteristic of each sub-array while at the same time it was established that eigenvectors of these matrices are statistically stable. Based on the peculiarities in the aerosol scattering coefficient profiles and taking into account their statistical properties we propose a four-level height model of the height distribution of the aerosol scattering coefficient.

Idea of this work is to use the spectral Fourier analysis of time series of lidar return fluctuations between two different heights. Formally, fluctuating signals from two heights can be considered as an input and output signal of a linear system. If the system is linear, the mutual phase spectrum is linear function of temporal frequency. We have used a simple and reliable method to estimate wind velocity, and the algorithm is to fix the frequency at which the phase spectrum reaches the value +/- (pi) or jump through zero of mutual phase spectrum function. The sign of phase angle means the direction of movement, i.e. upwards or downwards. The algorithm is applied to the real data of Micro Pulse Lidar (MPL) system. The MPL data provide an array of aerosol scattering coefficients up to the heights of 20 approximately 30 km with the sampling frequency of approximately 20 cycles per hour. In order to determine the vertical speed, the average time interval about 3 hours is required. The statistical reliability at single height is obtained by averaging several heights with the resolution of 1 km interval. From a spatial-temporal map of vertical motion in cloudy conditions, we find that there are downward movements of the air under the cloudy layers. That is the typical characteristics of cloud because when it moves down, cloudy drops are evaporated and also air temperature is lower. This dynamics promotes further acceleration of this process.

A potential source of errors at remote measurements of concentration of atmospheric gases by CO₂-lasers is the incomplete knowledge of atmospheric composition and temperature during measurements. This paper gives a general expression for errors owing to approximate description of the composition of the base of a statistical atmospheric model and of separate parameters measured during laser sounding. Measurements of additional atmospheric parameters are shown can reduce considerably the uncertainty in the concentration of a gas studied. A special computer code is designed to search pairs of frequencies with minimal error in mean-path horizontal measurements by using a topographic target. The performed calculations showed that a number of referenced experiments on remote measuring of atmospheric gas concentrations by CO₂-lasers were conducted at frequencies that did not provide the minimal atmospheric errors.6

Experimental investigations of the fluorescence intensity of plants in red spectral range induced by the laser radiation have been carried out. Dependence of the quantum yield of chlorophyll a fluorescence on plant species has been established and investigated. The largest range of seasonal variations of the fluorescence intensity was observed for the deciduous trees. Seasonal variations of the fluorescence intensity have the tendency to insignificant variations for the coniferous trees. Application of the fluorescence method to the remote specific categorization of the plant tissue and determination of the chlorophyll content is shown to be promising.

The article presents an algorithm for air density estimation by measuring test body movement parameters, based on the criteria of minimum of the generalized work functional. Air density estimation is based on Tikhonov's method of reverse problems regularization. The generalized work functional is used as the regularizing functional. Recommendations for applying a variant of the algorithm with usage of the predictive model are also compiled. The article also includes the comparison of the method with the Calmann filter. The results of modeling the estimation process assuming vertical movement of test body are included.

We present the coherent echo observation results obtained by Irkutsk Incoherent Scatter radar during September 25, 1998 ionospheric storm. It is shown that during that time we have observed scattering from irregularities elongated with Earth's magnetic field and located in the E-region of ionosphere. A good correlation between vertical component of magnetic field disturbance and logarithm of received power was found.

This paper gives a brief description of the incoherent scatter radar operated by the Institute of Solar-Terrestrial Physics at the Siberian Division of the Russian Academy of Sciences, located near Irkutsk, and exemplifies results obtained.

A new method of simultaneous acoustic sounding of vertical profiles of the thermal and velocity structure parameters and the outer scale of turbulence in the atmospheric boundary layer is suggested. The method was used to process the velocity and backscattered signal power measured with the Zvuk-2 three-channel monostatic Doppler sodar developed at the Institute of Atmospheric Optics of the SB RAS. The thermal structure parameter was reconstructed from the sodar measurements of the backscattered signal power. In so doing, the proportionality coefficient was determined with sodar calibration against the thermal structure parameter measured in developed convection with an ultrasonic thermometer/anemometer. The vertical profiles of the velocity structure parameter was determined from the transverse velocity structure function measured at the same range gate at different times. Peculiarities of the sodar- derived vertical profiles of the thermal and velocity structure parameters and the outer scale of turbulence are discussed. Contributions of the thermal and dynamic turbulence to the sound refractive index structure parameter are analyzed.

For remote measurements of rains, radars have been successfully used for many years. In the last decade, high- frequency acoustic radars (sodars) are being increasingly employed to measure the parameters of precipitation. They have a number of advantages over the conventional radars. In the present report, a new method of acoustic sounding of rain is described based on recording of the Doppler power spectra of falling raindrops comprised in the scattering volume with a high-frequency cw Doppler bistatic sodar. Differential acoustic scattering cross sections of a rigid spherical particle have been calculated with the use of the exact formulas of the Mie scattering theory as functions of the parameter p equals (pi) d/(lambda) , and the scattering angle (theta) , where d is the raindrop diameter and (lambda) is the acoustic radiation wavelength. Errors in reconstructing the normalized raindrop size distribution (NRSD) are numerically estimated. The NRSD's and the rain intensities reconstructed from raw spectra of real signals measured with cw bistatic Doppler sodars operating at frequencies of 5 and 40 kHz, respectively, are presented. The estimated rain intensities varied from 0.1 to 6.1 mm/h. The results obtained demonstrate that high-frequency sodars are very promising for measurements of rains.

The feasibility of retrieving information from lidar return signals has been discussed in connection with salient features of the formation of multiple scattering for different lidar field-of-view angles (FOVA). However, the aspects of hydrosol sensing connected with the presence of the rough air-water interface make the lidar signal interpretation more difficult. Results of a statistical simulation by the Monte Carlo method are presented in the report for a water scattering layer homogeneous with depth. peculiarities of the waveforms of the lidar signals recorded during a flight above Lake Baikal (in November 1996) and the Atlantic Ocean to the West of Great Britain (in June 1997) are discussed. We estimate that the effect of multiple scattering compensates for the effect of wind-driven sea waves when FOV angle is about p/2 equals 3 - 4 mrad, and that these FOVA are optimal for sounding.

A solution to the inverse problem of laser sensing of sea water is considered taking into account multiple scattering. Two forms of the lidar equation have been analyzed. The first form is based on the selection of the component caused by single scattering. The second form is based on the asymptotic signal, which would be recorded in case of unbounded field-of-view angle of the receiver. For each form of the lidar signal the iterative algorithms for the reconstruction of the extinction coefficient profile have been developed. The algorithms use physically justified functional relation between the extinction and scattering coefficients of sea water. The examples are given of the inversion of real lidar signals by the developed algorithms.

During the recent time it became visible the retrieval of passive methods for the atmospheric gases studying. This paper describes the method of ozone profile retrieving from the direct solar measurements obtained by the high resolution spectrophotometer in visible spectra range.

The results of a series of experiments with 12 acoustic computer-controllable sensors are reported in this paper. The experiments were conducted to study in detail the turbulence structure of low atmospheric layers. The measurements were accumulated at different schemes of the ultrasonic sensors spatial arrangement in horizontal and vertical planes. Based on the measurements obtained, the third and the fourth moment of wind velocity components and temperature fluctuations are considered. The dependence of skewness and kurtosis for a different of values measured at spatially separated point on the distance between the measurement points is obtained.

Differential Absorption Lidar Complex is designed for field scientific investigations, as well as for teaching Lidar designers and future operators. The Complex consists of two independently working Lidar Systems and the equipment for in situ measurements. Field test results are presented.

The results of 25-year work on design of middle IR ZnGeP₂ crystal growing technology are summed up, so as of the 20-year work on investigation of the parametric frequency converters with this crystal.

The problems of the polarization lidar transceiver optimization are considered. The basic features and the optimization criteria of lidar polarization units are presented and the comparative analysis of polarization units is fulfilled. We have analyzed optical arrangements of the transmitter to form the desired polarization state of sounding radiation. We have also considered various types of lidar receiving systems: (1) one-channel, providing measurement of Stocks parameters at a successive change of position of polarization analyzers in the lidar receiver, and (2) multichannel, where each channel has a lens, an analyzer, and a photodetector. In the latter case measurements of Stocks parameters are carried out simultaneously. The optimization criteria of the polarization lidar considering the atmospheric state are determined with the purpose to decrease the number of polarization devices needed.

The paper presents and discusses the programming and instrumental methods of increasing the accuracy of receiving and recording of lidar returns, performed in the photon- counting mode. Utility of these methods is demonstrated by the example of ozone sensing at Siberian lidar station.

The spatial distribution of laser beam itself and the alignment of the receiving-transmitting system are very important parameters in quantitative analysis of Lidar signal. This is important because the beam shape and the inclination angle between axes of the transmitter and receiver change the physical quality of detecting elements, for example, the aerosol scattering coefficient and the concentration of pollutants, etc. In practical alignment of Lidar system, the inclination angle is allowed to fluctuate within the receiver field of view. At a long distance where geometric overlap is complete, this fluctuation has no influence on the final results, but at a short distance this effect is serious. If we know the distribution of laser beam and inclination angle, this effect can be corrected by using geometrical overlap function. In this study, we have calculated the geometrical overlap function for Gaussian and uniform distributions, respectively. It is found that the ratio-function, which is defined as the ratio of two geometrical functions obtained from different angles between the axes of the transmitter and receiver, behaves in different way for Gaussian and uniform laser beams. The completely different behavior of these two ratio-functions for different beam types can be used more conveniently in identifying the laser beam shape and inclination angle than geometrical functions only. This fact can be used for characterizing the spatial distribution of laser beam and for testing of alignment between receiver and transmitter.

The present paper reports the experimental results and design of the laser systems developed for lidar experiments. The laser systems with radiation energy of hundreds of millijouls at each of several wavelengths allow to detect NO₂ and SO₂ atmospheric impurities. At the moment the laser system: powerful XeCl*-laser-dye laser is incorporated in a lidar developed at the Scientific Research Institute of Space Equipment (Moscow) for measurements of NO₂ content in the atmosphere.

The problem of measurement of a complex-shape signal with a broad dynamic range is discussed. A method of compensation measurement that uses an adaptive compensation signal close to the envelope of the measured signal is proposed. The compensation signal is formed by the conversion and smoothing of the main signal. The measured signal is reconstructed with a high discretization frequency by computer processing of the data obtained from the main and additional measuring channels. The scheme and measurement technique, peculiarities of lidar signal measurements and the results of operation testing are presented.

The antenna system intended for emission and reception of acoustic signals is one of the major parts of an acoustic radar. At present in our country the parabolic reflectors are gaining wide acceptance by virtue of relative simplicity of their design. In the present report, the results of theoretical and experimental investigations of a high- frequency acoustic antenna intended for sounding of the lower atmospheric layers at altitudes up to 200 m are presented.

In this paper we present results obtained at the first stage of development of Small Mobile DAS Lidar to control leakage of methane and methane-bearing gas mixtures. We developed three models that operate at 0.25; 12.5, and 200 Hz pulse repetition frequency. All three are small Optical Parametric Oscillators (OPO) based on KTP crystals pumped with Nd:YAG (1.064 micrometers ) or Nd:YA (1.079 micrometers ) lasers. They span the 1.52 to 1.58 and 3.2 to 3.5 micrometers ranges and allow to work on both the most intense and weak CH₄ absorption bands with the center at (lambda) equals 1.57 micrometers having the emission line width of 1 and 2.5 nm, respectively. The energies of single 5-ns emission pulses are equal to 4-5, 8- 10 and 15 mJ, respectively. It is enough for sensing up to 1 to 3-km distances with the sensitivity of 50 ppb/km. Second Harmonic Generation of OPO emission allows one to make measurements within 1.66 and 0.77 micrometers CH₄ absorption bands.

For lidar receivers, spatial filtration problems with separate recording of the multiply backscattered flux incident at different angles relative to the optical axis of the receiving lens are considered. Beam separation is performed with spatial filters selecting image fragments within the lidar receiver field of view, which greatly exceeds the transmitted beam divergence. Various instrumental realizations of spatial filter-separators are examined, such as multielement photodetectors with concentric rings, multifiber and refractive separators, and changeable diaphragms. Possibilities and peculiarities of simultaneous and sequential recording of image fragments are considered.

The radio-optical technique for determination of the road surface condition is proposed. In the optical part the road surface condition is determined by the depolarization degree of linearly polarized radiation reflected from the road surface. The paper describes the results of model tests on asphalt covered with snow, ice and snow-water mixture. The radiowave part of the setup makes it possible to detect the presence of ice under snow layer.

Cause and effect relation between environment changes and climate, as well as influence of the regional peculiarities and anthropogenic factors on these changes, are considered as basic problems for multidisciplinary studies, which require new methodic approaches. We used the leading atmospheric process associated with solar flux transfer in the aerosol atmosphere to illustrate new approaches describing radiation state changes and its sensitivity to the atmospheric aerosol content.

The characteristics of a helicopter-borne lidar based on tunable TEA CO₂ laser and its third harmonic designed for remote detecting the methane and ammonia leakages from pipe-lines are analyzed numerically. The spectral range near 3 micrometers is shown to be most promising for remote sensing of methane emissions. Parameters of radiation of the tunable pulse-periodic mini-TEA CO₂ laser and generators of harmonics to be utilized in the helicopter-borne differential absorption lidar are estimated. Emissions of different gases intensity are analyzed for possible detectability at a distance up to 1 km. The use of the third harmonic of the TEA CO₂ laser allows methane emissions from a pipe-line to be detected and measured with mean measurement error from 10 to 15% for methane concentrations varying from the background level to the explosion-hazardous one. The optimal pair and possibilities of the ammonia remote sensing on the base of the first harmonic of TEA CO₂ laser was determined as well.

The urgence of studies of minor gas constituents (MGC) variations in the atmosphere is necesitated by several causes. The basic one is connected with the need to forecast climatic and ecological consequences of air composition changes as a result of man-made impact. A constant increase of such active in IR absorption gases as carbon dioxide, methane, dinitrogen monoxide is a real fact. A knowledge of tendencies in the atmospheric gas composition and its linkes with natural and anthropogemc factors is necessary for diagnostic estimations of thermal (radiation) balance changes and of the Earth's climate. The necessity of monitoring the toxic carbon monoxide content in the atmospheric boundary layer is caused by increasing CO emission due to growing traffic that presents a considerable ecological problem for large populated areas. The methods for measuring MGC in the atmosphere are very different. In the world monitoring network containing now more than two dozens of stations special, highly-accurate instrumentation (gas chromatographs and optico-acoustical gas analyzers) are used there as a rule [1]. The list of gases for monitoring includes carbon dioxide, methane, dinitrogen monoxiue and some freons. Rather widely used is the method of spectral analysis based on solar infrared (IR) radiation absorption in the atmospheric column [2]. Well-known are different methods of air pollution remote control with the use of laser radiation sources. The paper presents the measurement results for methane, dinitrogen monoxide and carbon oxides contents in air samples obtained by the method of spectral analysis in the IR spectral range with a Fourier-transform spectrometer and a multipass cell.

Water vapor and methane containing in the atmosphere are minor gas constituents affecting its radiation properties causing a greenhouse effect. An increase of greenhouse gases contents enhances the greenhouse effect and results in climate warming as the observations have shown. The spectroscopic method and spectrometric instrumentation used for ground-base observations make it possible to measure total contents ofwater vapor and methane in the atmospheric column and to control the contents of these gases in the atmosphere. Systematic groundbased measurements ofwater vapor and methane contents in the atmosphere at the territory of Russia with the use of different modifications of the spectroscopic method and instrumentation are made in the Institute of Experimental Meteorology, SPA "Typhoon" (IEM) ' , inthe Institute of Atmospheric Physics of the Russian Academy of Sciences (lAP) 4-6 and in the Scientific and Research Institute of Physics, St. Petersburg State University (SRIP) .The measurements are carried out in observation sites sth different geographical location and local conditions. A most comprehensive experimental substantiation of reliability and relevance of long-term measurement results in different experimental sites obtained with the use of different methods and instrumentation are independent simultaneous comparative measurements in one site and joint measurements in different sites. Simultaneous spectroscopic measurements of methane content in the atmosphere carried out with research teams from IEM, lAP and SRIP were made in September 1997 and by the ffiM and lAP scientists in MarchApril 1998 in Zvenigorod at the lAP scientific station (55°42' N, 36° 48' E, 200 m above the sea ev8 .In September-December 1998 SimultaneOus measurements ofwater vapor and methane in the atmosphere were performed at the same site by IEM and lAP teams. At the same time the scientists from SRIP perfonned the measurements of water vapor and methane contents in Petrodvoretz at the SRIP scientific station (59°54' N, 29° 48' E, 20 m above the sea level). The results ofthese measurements are given and discussed below.

Phenols are the most widespread pollutants of the environment in the world. Investigations of phenol photolysis are of great importance as concerning the phenol removal from water. The experiments have been performed to study phenol phototransformations in aqueous solution at various pH of the samples under UV irradiation. The fluorescence and absorption spectra were recorded. The spectra analysis shows that phenol molecule changes its ionic form under the irradiation. The phenol dimers and other products of photolysis are produced. Strong dependence of phenol photoprocesses on pH was also noticed.

The three-week spatiotemporal variability of the meteorological state of the lower atmosphere of a local region has been analyzed based on data obtained at three measurement sites. Interrelation and correlation of different meteorological parameters measured at these sites is studied.

The paper analyzes secondary phenomena of atmospheric radioactive pollution caused by activity of the nuclear cycle enterprises. These effects being as indicators for remote diagnostics of a radio-activity are discussed. Excitation of a molecular and gas component in the air and various chemical reactions under the action of radiation have been considered. As a result of these reactions, new aerosol and gaseous components in the form of the exited atoms and ions appear in the atmosphere and relax with emission including microwave and optical wavelengths. The observable luminescence of the air during the emergency events at the nuclea power stations are long enough to be detected by modern receivers. Intensity of such radiation in a radioactive plume is estimated for ecological monitoring of the atmosphere. Aerosols appearing, as a result of UF₆ hydrolysis, in the atmosphere and their behavior have been also shown to be detectable with remote sensing.

The results of the statistical evaluation of quality and efficiency of the modified method of clustering of the arguments (MMCA) are discussed for applications in numerical forecast (for a period of 12 - 48 hours) of the averaged over layers temperature profiles and profiles of the zonal and meridional mean wind components. This procedure is aimed at providing a meteorological support in the problem of forecasting atmospheric pollution processes. The statistical evaluation of the quality of this method carried out using the data of long-term observations at two aerological stations: Brest and Novosibirsk has shown the algorithm MMCA to be efficient enough for the preliminary calculations of the average temperature for a period up to 48 hours, and for mean wind components -up to 24 hours.

Three kinds of gas analyzers designed for continuous monitoring of the sulfer and nitrogen oxides in the exhaust gases of a power plant are described. The operation of gas analyzers is based on use of laserless UV sources and differential absorption method. High efficiency of gas analyzers developed has been demonstrated under industrial conditions.

The differential Raman cross sections and depolarization ratios for N₂ and O₂ molecules for 10 low vibrational states were calculated. The method of their calculation uses experimental polarizability derivatives of scattering diatomic molecules. These Raman scattering parameters can be used for diagnostics of the vibrationally- excited gas media.

Results of investigation of total ozone in the atmosphere over Siberian Range in the first half of 1998 using data of infrared and ultra-violet sensing from satellites are presented. It was found that infrared data from NOAA satellites provide quite reliable information on the ozone layer over Siberia.

The idea and methods of a combined use of mathematical models and observed data for monitoring and prediction of transport and transformation of aerosols is presented.

Reported is the description and current state of the project `Information-Computational System `Integrated Model of Atmospheric Optics'. The system will incorporate the sets of data of the atmosphere, compiled during laboratory and field measurements conducted at the Institute of Atmospheric Optics experimental and theoretical models developed for forecasting and calculation of the latter. At the first stage the Integrated model will comprise only a few blocks, namely, the block of aerosols, molecular spectroscopy, atmospheric radiation and the photochemistry block.

Results are presented of the authors' approach to prognosis of possible qualitative changes in the long-term behavior of complex atmospheric-optical processes on the base of the nonlinear dynamics analysis of the corresponding low-order model. In particular, the behavior of chemical composition of the atmosphere determining its optical properties in many respects is discussed. To this end the qualitative analysis of dynamics of the pure oxygen atmosphere within the box model is fulfilled and conditions of appearance of multiple steady states are determined. It is shown that a simple model relating the kinetics of oxygen components, water vapor and molecular hydrogen allows one to predict different types of behavior of oxygen components in the hydrogen- oxygen atmosphere.

Models and methodological developments in Geographical Information Systems (GIS) for regional environmental analysis and environment rehabilitation are considered. Generalized environmental pollution index taking into account arbitrary number of chemical contaminants in environment is introduced for solving the region environmental problems. An approach to identifying of environmental danger zones on a region territory was developed. The zones are represented on a computer map of the region. A procedure of choosing of the technologies for cleaning air with the use of geoinformation technologies on the basis of the results of the regional environmental analysis is developed. The procedure is suitable for development of practical recommendations for a choice of nature-protection technologies on the basis of the analysis and prediction of changes of the environment. A procedure of predicting environmental danger zones evolution is discussed. The procedure is based on analysis of the regional economic development scenario. The results of analysis of regional environmental state with application of GIS-technologies are illustrated on computer maps.

The atmospheric chemistry information-computational system (ICS) with Internet access is presented. The ICS is aimed summarizing fundamental data on atmospheric processes, determining the dynamics of complex chemical systems and providing educational information. The system consist of three functional blocks: data preparation, computation and information blocks, within which a user may choose the chemical reactions and atmospheric models, drive relevant kinetic equations and conservation laws, solve the kinetic equations, visualize the results of calculations and get access to related information.

In practical applications of lidar sounding, it is often difficult for the devices which work on various physical measurements to estimate meteorological parameters of the atmosphere. One of the difficulties is to define the slow vertical speed of the aerosol motion. This study is based on statistical processes at a spatial frequency domain after long-term observation of aerosol motion with the help of Micro Pulse lidar or other lidar systems. Basic assumption of the aerosol model is that an inhomogeneous aerosol distribution of certain size has initially uniform spatial arrangement. Simultaneously, we also assume that there are two more different aerosol distributions whose size is two times smaller than the initial one. The resulting aerosol field is a superposition of inhomogeneous aerosol distribution of the different sizes. The randomness of the aerosol distribution is provided with the random-number generator which changes the size and the position of each inhomogeneous aerosol distribution in the given limits. In this work, we have presented a 2D aerosol field whose size is 25.6 km in a vertical direction and 256 km in horizontal direction. The number of the basic aerosol sizes to which random factor is added is equal to seven. The size of inhomogeneous aerosols in a horizontal direction has changed from maximal value and the vertical size of inhomogeneities is setup by the special parameters from which shape of the each inhomogeneity is determined.

The methodology and accuracy estimates of numerical reconstruction of the missing information by the regression methods from the data of ground-based observations or the data obtained for lower altitude levels are considered as applied to wind lidar sensing. It is shown that the bivariate linear regression method can be used to reconstruct the vertical wind profiles only at altitudes up to 100 - 250 m, and the method of multidimensional extrapolation provides good results of reconstruction of these profiles at altitudes up to 1000 - 1200 m from the data obtained for the layer 0 - 300 m in winter and 0 - 500 m in summer.

Software for qualitative analysis of the kinetic equations of atmospheric chemistry on the base of parallel algorithms are developed and tested. It includes dispatcher for managing parallel tasks and the parallel algorithms for solving algebraic and differential equations on computer clusters. Tests have shown the efficiency of the computing using this architecture and the parallel programming. The data format for translation from symbolic kinetic equations to procedures of computation block is discussed as well.

We describe a geoinformation interactive system for predicting and taking into account the effect of the entire set of linear optical phenomena that may occur in the atmosphere on the performance characteristics of optoelectronic systems and devices intended for operation in the atmosphere. Geoinformation interactive system is a set of applied programs that incorporates the engineering techniques and summarizes the results of fundamental research in the atmospheric optics. The system can provide a versatile service. The system makes it possible to present promptly the results in the form of tables, histograms and plots.

We have used the client-server Delphi 3.0, Borland Int., for fast development of the applications as a tool of creating an executive system utility for a computer system to calculate the effect of the atmosphere on the accuracy and power characteristics of optoelectronic devices because of certain is advantages of this environment over others.

The database on the atmospheric chemistry was developed for storage of related information and data. It forms a basis of data preparation block for the information-computational system `atmospheric chemistry'. The necessity of usage of the virtual data is discussed. Data structure, data model and user interfaces are described.

Our recent studies of the continuum absorption of radiation by pure water vapor has been extended to the case involving air-broadening. A specific nonlinear absorption dependence has been derive for inhomogeneous optical media. The computations are performed by an original information system AIRSENTRY. The absorption within the short-wave region is a linear function of the partial pressure of water and of the total pressure. The absorption by water vapor in the atmosphere and the Rayleigh scattering are taken into account in order to describe in situ experiments and a good coincidence with measurements is observed for the optical depth calculated up to the spectral region of 20000 cm^-1. The discrepancies among experimental data of various authors may be explained by different path parameters used, since the latter are sensitive in the nonlinear absorption analysis. A solution of the enhancement problem is suggested for both transmission windows and absorption bands. The continuum conception used in the present studies suggests that all lines to be for all the absorbers and buffer gases in the WV, IR, and UV region contribute to the continua via either the pure absorption or the hypothetical nonlinear molecular absorption-scattering phenomenon.

In the work, the automated system `Photon' for statistical modeling of a radiation field of the atmosphere is presented. The scheme of functional construction of the system, a list of problems solved by the system and the database contents are given.