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Atmospheric and Oceanic Optics

2013 year, number 5

Structure of the spatial-temporal spectrum of laser beam in the atmosphere under strong turbulence

D.A. Marakasov
V.E. Zuev Institute of Atmospheric Optics of Siberian Branch of the Russian Academy of Science,
Tomsk 1, Academician Zuev square, Tomsk, 634021, Russia
Keywords: wind profile, reconstruction, spatio-temporal spectrum, strong intensity fluctuations regime

Abstract >>
In this paper, the analysis of the possibility of spatio-temporal filtering of the correlation function of laser beam intensity in the turbulent atmosphere at strong optical turbulence regime is presented. It is shown, that, despite significant distortions in the high-frequency band of spatio-temporal spectrum in comparison with weak turbulence regime, the increase of the temporal delay between the frames allows to separate the impacts of different intervals of the optical path. The characteristic scales of spectral responses differ essentially from current point coordinate along the path. This allows extracting the information about the wind velocity profile.

Energy light structures during femtosecond laser radiation filamentation in air.
To the 50th anniversary of the first publication of light self-focusing

A.A. Zemlyanov, A.D. Bulygin, Yu.E. Geints
V.E. Zuev Institute of Atmospheric Optics of Siberian Branch of the Russian Academy of Science, Tomsk,
Academician Zuev square, Tomsk, 634021, Russia
Keywords: self-focusing, filamentation, refocusing, diffraction-beam tube

Abstract >>
A class of energy light structures in nonlinear wave physics, so called diffraction-beam tubes in a self-focusing dissipative medium, is established. It is shown that their interaction along a propagation distance of high-power femtosecond laser radiation forms areas of light energy localization, stable in the sense of the physical characteristics, i.e., filament and post-filamentation channel, as well as conservative periphery. Stabilization of boundaries of the mentioned areas is provided by additional contraction of diffractive nature from the side of periphery. The dependences of filamentation length of a laser pulse on power and beam radius and the fact of high intensity conservation in the post-filamentation light channel are interpreted using this concept.

Termal self-action of high-power continuons pulse-periodic CO2 laser radiation in air. I. Numerical modeling of transfer along the atmospheric path

Yu.E. Geints1, G.N. Grachev2, A.A. Zemlyanov1, A.M. Kabanov1, A.A. Pavlov2, A.G. Ponomarenko2, V.N. Tishchenko2
1V.E. Zuev Institute of Atmospheric Optics of Siberian Branch of the Russian Academy of Science, Tomsk
Academician Zuev square, Tomsk, 634021, Russia
2Institute of Laser Physics of Siberian Branch of the Russian Academy of Science,
13/3, Ac. Lavrentyev's prosp., Novosibirsk, 630090 Russia
Keywords: laser radiation, propagation, absorption, thermal lens, defocusing, modeling

Abstract >>
A problem of transportation of high-power laser radiation energy at a wavelength of 10.6 μm in the atmosphere is theoretically considered under the conditions of development of its thermal and wind nonlinearities. The power characteristics of continuous and pulse-periodic radiations during propagation along a surface kilometer-long atmospheric path at sharp focusing onto receiver are studied. The main factors having the largest effect on distribution of the influencing radiation are determined. It is established that one succeeds in reducing of undesirable effect of thermal defocusing using a train of low-power short pulses with rather high repetition rate at the expense of the effect of light-induced “blooming” of the gas medium. The questions of scaling of the optical paths from the viewpoint of their equivalence in appearing of thermal nonlinearity are discussed.

Numerical simulation of combined beams propagation in the turbulent atmosphere in conditions of the thermal blooming

V.A. Banakh, A.V. Falits
V.E. Zuev Institute of Atmospheric Optics of Siberian Branch of the Russian Academy of Science, Tomsk,
Academician Zuev square, Tomsk, 634021, Russia
Keywords: simulation, thermal blooming, combinied beam

Abstract >>
The simulation algorithms of propagation of the coherent and incoherent combined beams in a turbulent atmosphere under conditions of thermal blooming are presented. The properties of focused combined beams in comparison with the equivalent Gaussian beam are studied. It is shown that there is a complex diffraction pattern of the coherent combined beams fields. Nevertheless, the maximal intensity in the beam crossection is almost the same both for coherent and incoherent combined beams, as well as for Gaussian beam if the nonlinearity parameter exceeds unity. In the conditions of strong optical turbulence and strong thermal blooming the integral characteristics of the combined beams are close to those of a Gaussian beam, which has an effective size commensurable with the size of combined beams. Turbulent fluctuations of the intensity of incoherent combined beams are less than those of coherent combined beams.

Laser method of approximate measurement of instantaneous wind velocity and direction

V.I. Kozintsev, S.E. Ivanov, M.L. Belov, V.A. Gorodnichev
Scientific-Research Institute of Radioelectronics and Laser Technology at the N. E. Bauman Moscow State Technical University,
2-ya Baumanskaya st., 5, Russia, 107005, Moscow,
Keywords: instantaneous wind velocity and direction, laser remote sensing method

Abstract >>
In this paper a laser method of approximate measurement of instantaneous wind velocity and direction in the atmosphere is considered. It is shown that analysis of spatial realization of atmospheric aerosol backscatter coefficient allows one to find approximate value of instantaneous wind velocity with an accuracy of ~ 20–30% for modulus and ~ 25–30° for direction.

Peculiarities of the depolarization ratio in lidar signals for randomly oriented ice crystals of cirrus clouds

A.V. Konoshonkin1,2, N.V. Kustova1, A.G. Borovoi1
1V.E. Zuev Institute of Atmospheric Optics of Siberian Branch of the Russian Academy of Science, Tomsk
Academician Zuev square, Tomsk, 634021, Russia
2Federal State Educational Institution Of Higher Professional Education"National Research Tomsk State University" (Tsu),
36, Ave. Lenina, Tomsk, 634050, Russia
Keywords: polarization of light, lidar signal, cirrus clouds, Mueller matrix

Abstract >>
Numerical solution for the problem of light scattering by randomly oriented hexagonal crystals has been firstly obtained. A possibility for retrieving both sizes and shapes of hexagonal ice crystals by the use of the depolarization ratio of lidar signals is shown.

Estimation of global fluxes of CO2 for 2009–2010 using ground-station and space-borne (GOSAT) observation data with empirical orthogonal functions

R.V. Zhuravlev1, A.V. Gan’shin1, Sh.Sh. Maksyutov2, S.L. Ochshepkov2, B.V. Khattatov3
1Central Aerological Observatory,
3, Pervomayskaya str., Dolgoprudny, Moscow region, 141700, Russia
2National Institute for Environmental Studies,
16-2 Onogawa, Tsukuba, Ibaraki, 305-8506, Japan
3Fusion Numerics International LLC,
373 Arapahoe Ave, Boulder, CO, USA, 80302
Keywords: greenhouse gases, atmosphere, modeling of admixtures transport, inverse problems

Abstract >>
Inverse problem of atmospheric transport has been applied to estimate surface fluxes of CO2 for 2009–2010 using station and space-borne (GOSAT) observation data. Flux adjustments for each kind of sources are represented as a linear combination of main flux components according to surface gas exchange. For atmospheric transport simulation we used coupled Eulerian-Lagrangian model (GELCA model). Due to a huge amount of observation data per month (3000–5000) we used Fix-Lag Kalman Smoother for solving inverse problem that allows us to estimate monthly fluxes successively according to the chosen assimilation window. Results were presented as 2D fields of monthly surface fluxes for each kind of sources. Our calculations show the significant uncertainty reduction of fluxes in case of including GOSAT observations.

Spectroscopic factors, influencing the accuracy of the atmospheric radiative transfer simulation in the methane absorption bands in the near infrared region

T.Yu. Chesnokova
V.E. Zuev Institute of Atmospheric Optics of Siberian Branch of the Russian Academy of Science, Tomsk
Academician Zuev square, Tomsk, 634021, Russia
Keywords: atmospheric radiative transfer, methane, absorption lines

Abstract >>
The analysis of basic spectroscopic factors, influencing atmospheric radiative transfer simulation in the methane absorption IR bands, which are used in the tasks of methane total content retrieval from the atmospheric solar spectra measurements, is carried out. The role of methane and water vapour absorption line parameters uncertainties and difference of extraterrestrial solar spectrum models is considered. A comparison with measured atmospheric spectra is made.

Information-calculating system for studying spectral-angular characteristics of solar radiation

S.Yu. Andreev, T.V. Bedareva
V.E. Zuev Institute of Atmospheric Optics of Siberian Branch of the Russian Academy of Science, Tomsk
Academician Zuev square, Tomsk, 634021, Russia
Keywords: numerical modeling, solar radiation, aerosol, relational data base

Abstract >>
An information-calculating system (ICS) «SoRad» for studying spectral-angular characteristics of solar radiation is presented. The structure and the principal objectives of the ICS, the model of the atmosphere for radiative calculations, and the relational data model developed in this subject field are described. The paper also contains the description of the client application interface, its functions, the algorithm for data base filling by means of the application. The questions about information system functionality development by external dynamic link library are discussed. The calculated and systematized data may provide the basis for different studies.

Decomposition of the observed temperature and sunspot number sets. Features of the mean-values

V.A. Tartakovsky, A.I. Kuskov
Institute of Monitoring of Climatic and Ecological Systems of the Siberian Branch of the RAS,
10/3, Academichesky ave., 634055, Tomsk, Russia
Keywords: synchronism, essential indicators, external forcing

Abstract >>
A hypothesis is putts forward assuming that the external forcing action synchronizes the climatic processes and manifest itself in the similarity of their essential indicators. Orthogonal components of processes, differing in coincidence or non-coincidence of the essential indicators are introduced. The theory is applied to decompose a series of temperature and the Wolf numbers. It is found that the average quantities of orthogonal components of temperatures form areas either positive or negative values. In the same areas, delinited by the zero isotherms, fall average quantities of the same components of the Wolf numbers. Compliance with the physics of climatic processes is confirmed by the intersection near the vernal equinox of annual cycle of the numbers of the weather stations, which belong to the areas of monthly average positive or negative temperatures. A new tool is found to analyze the information contained in the observation data of climatic processes.

Formaldehyde pollution of the urban atmosphere as a function of certain meteorological factors

T.S. Selegei1, N.N. Filonenko1, V.A. Shlychkov2, A.A. Lezhenin3, T.N. Lenkovskaya1
1Siberian Regional Hydrometeorological Research Institute,
30, Sovetskaya st., 630099, Novosibirsk, Russia
2Novosibirsk Division of Institute for Water and Environmental Problems of the Siberian Branch of the RAS,
Morskoy ave., 630090, Novosibirsk, Russia
3Russian Academy of Sciences Mathematical Department Novosibirsk Scientific Centre Institute of Computational Mathematics and Mathematical Geophysics SB RAS,
prospect Akademika Lavrentjeva, 6, Novosibirsk, 630090, Russia
Keywords: atmosphere pollution, formaldehyde concentration, meteorological and synoptic processes, statistical analysis, Tomsk

Abstract >>
The impact of the major meteorological processes on the concentration of formaldehyde in the city of Tomsk is studied. It is shown that the highest concentrations are mostly established at low atmospheric pressures in a combination with high air temperatures. The relative humidity effect is insignificant. The weak precipitation reduces the pollution concentration. The amount of background formaldehyde pollution caused by the permanent man-made and natural sources is determined. The grouping of various types of synoptic processes in five compact classes being signs of possible formation of high concentration of formaldehyde is proposed.

Investigation of possibility to improve the efficiency of adaptive system of “Luch” facility

S.G. Garanin, A.I. Golubev, V.M. Povyshev, F.A. Starikov, R.A. Shnyagin
Federal State Unitary Enterprise, Russian Federal Nuclear Center — All-Russian Research Institute of Experimental Physics', Sarov, Nizhny Novgorod region, Russia,
37, pr. Mira, 607188, Sarov, Nizhny Novgorod region, Russia
Keywords: adaptive mirror, phase correction of laser beam, optical aberrations, stochastic parallel gradient algorithm, laser irradiation

Abstract >>
The methods of the control of a wide-aperture 61-element adaptive mirror implemented at the “Luch” facility are numerically investigated. These methods are based on the stochastic parallel gradient (SPG) algorithm and the least-squares approach (LSA) for control voltage calculation. The capability of the adaptive mirror is determined regarding to correction of phase aberrations. It is found that SPG algorithm is capable to practically completely realize the potential of the adaptive mirror on the energy focusing. By means of SPG algorithm it is possible to obtain more efficient correction of the laser beam aberrations in comparison with that realized in the experiments under conventional adaptive mirror operation mode based on the phase measurement by a wavefront sensor. A combined method (based on SPG algorithm and LSA) of adaptive mirror control is proposed. By means of this method it is possible to obtain the laser energy in diffraction angle at a level of 40% and the Strehl number at a rate of 0.4.

Generation of two-phase gas-droplet flows with preset characteristics

A.N. Ishmatov1, V.V. Elesin2, A.A. Trubnikov1, S.P. Ogorodnikov2
1Institute for Problems of Chemical and Energetic Technologies of the Siberian Branch of the RAS,
Sotsialisticheskaja str. 659332, Biysk, Russia
2Joint Stock Company Federal Research and Production Center ALTAI,
Sotsialisticheskaja str. 659332, Biysk, Russia
Keywords: gas-drop flow, aerosol, simulated aerosol media, atomization of liquids, aerodynamic atomization, separation of droplets

Abstract >>
The problem of creating of finely dispersed gas-drop flow and aerosols with specified characteristics (dispersion, concentration, flow rate) for a wide range of scientific problems is solved. The possibility for efficiently producing of fine fraction of droplets with defined dispersiveness was demonstrated.