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Atmospheric and Oceanic Optics

2017 year, number 12

Filamentation of an ultrashort laser pulse train in air

Yu.E. Geints, A.A. Zemlyanov
V.E. Zuev Institute of Atmospheric Optics of Siberian Branch of the Russian Academy of Science, 1, Academician Zuev square, Tomsk, 634021, Russia
Keywords: ультракороткое лазерное излучение, самофокусировка, лазерная филаментация, лазерная плазма, цуг импульсов, ultrashort laser radiation, pulse self-focusing, laser filamentation, laser plasma, pulse train

Abstract >>
The results of numerical simulation of self-action in air of a sequence of ultrashort laser pulses with a carrier in the near and mid-IR regions are presented. We show that the use of a 10.6-mm pulse train allows appreciable elongation of the plasma channel generated during pulse filamentation and enhancement of its spatial connectivity. The filamentation of a submicron pulse train does not visibly change the filamentation region characteristics.

Use of results of acoustic diagnostics of the atmospheric boundary layer for estimation of the influence of turbulence on laser beam characteristics

S.L. Odintsov, V.A. Gladkikh, A.P. Kamardin, I.V. Nevzorova
V.E. Zuev Institute of Atmospheric Optics of Siberian Branch of the Russian Academy of Science, 1, Academician Zuev square, Tomsk, 634021, Russia
Keywords: лазерное излучение, пограничный слой атмосферы, турбулентные искажения, распространение, содар, структурная характеристика показателя преломления, laser emission, atmospheric boundary layer, turbulent distortions, propagation, sodar, structure characteristics of refractive index

Abstract >>
Estimates of the radius of coherence of a laser beam and the possible beam broadening in the atmospheric boundary layer under the effect of random inhomogeneities of the refractive index, determined from experimental data of remote acoustic sounding, are presented. The possibility of significant loss of coherence and marked broadening of the laser beam due to turbulence in nighttime conditions is noted.

Operative estimation of ecological state of coastal sea aquatories using passive optical remote sensing of water surface from board a ship

V.V. Rostovtseva, I.V. Goncharenko, B.V. Konovalov, A.F. Alukaeva
P.P. Shirshov Institute of Oceanology, 36, Nakhimovski prospect, Moscow, Russia, 117997
Keywords: экологическое состояние морских акваторий, спектры коэффициента яркости моря, поглощение и рассеяние света морской водой, приустьевая акватория, концентрации взвеси и окрашенного органического вещества, ecological state of marine areas, spectra of the sea radiance coefficient, absorption and scattering of light by sea water, coastal sea water area at the river mouth, concentration of suspended matter and colored organic matter

Abstract >>
Study of ecological state of marine coastal regions often requires operative acquisition of detailed data. In this work, the measurements of the sea radiance coefficient spectra are analyzed, which were made with a new three-channel passive optical complex for ecological monitoring of marine aquatoria (EMMA) developed by us, which operates semiautomatic from board a moving ship. The measurements were carried out at the Brazilian coast in the area of the Rio Grande river mouth. The spectra obtained were processed using an original technique based on intrinsic properties of the pure sea water absorption spectrum (WASM - water absorption step method) modified for the eutrophic type II waters. This enables us to estimate the absorption indices of the suspended matter and colored organic matter. The comparison of these remote estimates with the estimates retrieved from the water samples taken at special stations shows their high correlation. Using remotely obtained data the distributions of the suspended matter and colored organic matter were constructed and compared to the satellite image in the aquatory under exploration.

Broadening and shift of the methane absorption lines in the 11000-11400 cm-1 region

V.I. Serdyukov, L.N. Sinitsa, A.D. Bykov, A.P. Shcherbakov
V.E. Zuev Institute of Atmospheric Optics of Siberian Branch of the Russian Academy of Science, 1, Academician Zuev square, Tomsk, 634021, Russia
Keywords: метан, фурье-спектрометр, поглощение, интенсивность, полуширина, сдвиг линии, methane, Fourier spectrometer, absorption, line strength, halfwidth, line shift

Abstract >>
Absorption spectra of methane in the 11000-11400 cm-1 region were recorded at a IFS-125M Fourier spectrometer at pressures from 11 to 100 mbar, room temperature, and spectral resolution of 0.03 cm-1. A multipass cell 60 cm long and 44 passes were used, which provided a total path length of 2640 cm and threshold sensitivity to absorption on an order of 10-8 cm-1. Voight contour parameters (line center, intensity, self-broadening and self-shift coefficients) were determined.

Sorption of atmospheric gases (N2, O2, Ar, CO2, and H2O) by silica aerogel

B.A. Tikhomirov
V.E. Zuev Institute of Atmospheric Optics of Siberian Branch of the Russian Academy of Science, 1, Academician Zuev square, Tomsk, 634021, Russia
Keywords: кремниевый аэрогель, атмосферный газ, адсорбция и десорбция, silica aerogel, atmospheric gases, adsorption and desorption

Abstract >>
Adsorption and desorption of atmospheric gases (N2, O2, Ar, CO2, and H2O) in silica aerogel is studied. Static parameters of adsorption and kinetic parameters of adsorption and desorption are determined based on pressure vs time dependence P(t) in the buffer vacuum chamber of the experimental setup during adsorption and desorption of gases by a SiO2 aerogel sample of V = 42.8 cm3 in volume and ρ = 0.34 g/cm3 in density. The ratios of adsorbate molecular density to aerogel molecular density at the room temperature T = 293 K and equilibrium pressure Pр ≈ 1 bar are found: γ(N2) = (9 +- 3)% (9 molecules of N2 adsorbed by pore surface to 100 N2 molecules in the gas at equilibrium), γ(O2) = (7 +- 3)%, and γ(CO2) = (222 +- 8)%; for water vapour, γ(H2O) = (5.9 +- 0.3) x 104% at the pressure Pр = 5.7 mbar. It is ascertained that argon atoms are not adsorbed by the aerogel. It is suggested to use argon as a “zero” gas in spectroscopy of molecules adsorbed by SiO2 aerogel to determine the amount of adsorbate in a sample. A sum of two exponents with kinetic parameters τ1 and τ2 is used to fit P(t) dependence. The τ1 and τ2 values are estimated during adsorption and desorption of each gas under study.

Variability of PM2.5 surface concentrations in Moscow according to MSU meteorological observatory data

D.P. Gubanova1,2, I.B. Belikov1, N.F. Elansky1, A.I. Skorokhod1, N.E. Chubarova3
1A.M. Obukhov Institute of Atmospheric Physics Russian Academy of Sciences, Pyzhevsky per., 3, 119017, Moscow, Russia
2Karpov Institute of Physicsl Chemistry, 10, Vorontsovo pole street, Moscow, 105064
3Lomonosov Moscow State University, GSP-1, Leninskie Gory, Moscow, 119991, Russia
Keywords: аэрозоли, массовая концентрация аэрозолей РМ, малые газовые составляющие атмосферы, состав атмосферы, аэрозольная оптическая толщина, загрязняющие примеси, aerosols, РМ, trace gases, atmospheric composition, aerosol optical depth, atmospheric pollutants

Abstract >>
Temporal variability of PM2.5 surface concentrations in Moscow and its dependence on other atmospheric parameters, such as trace gas concentrations, aerosol optical thickness (AOT), surface air temperature, humidity, and wind speed have been considered. Data rows of PM2.5 and SO2, NH3, NOx, CO, and O3 obtained during continuous measurements in 2011-2013 have been analyzed. Daily and seasonal variations in PM2.5 and trace gas concentrations as well as correlations between them have been studied. The variability of PM2.5 concentration has been considered in relation to trace gases participating in atmospheric aerosol formation and to meteorological parameters. Data on PM2.5 surface concentrations have been compared with aerosol optical depth (АОТ500) measured at the same site.

The vertical distributions of gaseous and aerosol admixtures in air over the Russian Arctic

O.Yu. Antokhina1, P.N. Antokhin1, V.G. Arshinova1, M.Yu. Arshinov1, B.D. Belan1, S.B. Belan1, D.K. Davydov1, G.A. Ivlev1, A.V. Kozlov1, P. NГ©dГ©lec2, J.-D. Paris3, T.M. Rasskazchikova1, D.E. Savkin1, D.V. Simonenkov1, T.K. Sklyadneva1, G.N. Tolmachev1, A.V. Fofonov1
1V.E. Zuev Institute of Atmospheric Optics of Siberian Branch of the Russian Academy of Science, 1, Academician Zuev square, Tomsk, 634021, Russia
2Laboratoire d’AГ©rologie UMR5560, UniversitГ© Paul Sabatier de Toulouse, 14, Avenue E. Belin, 31400, Toulouse, France
3Laboratoire des Sciences du Climat et de l’Environnement, Unite mixte CEA-CNRS, Bat709, CEL’ Orne des Merisiers 91191 GIF SUR YVETTE, Paris, France
Keywords: Арктика, атмосфера, аэрозоль, воздух, вертикальное распределение, газы, континентальный, крупномасштабный, пространственный, Arctic, atmosphere, aerosol, air, vertical distribution, gases, continental, large-scale, spatial

Abstract >>
The vertical distributions of gas and aerosol compositions of air over the Kara Sea and coastal areas of the Russian Arctic, measured by Tu-134 Optic airborne laboratory in October, 2014, are analyzed. Features of the altitude distributions of CO2 and aerosol over the Kara Sea that differ them from continental conditions are revealed. No considerable deviations from continental distributions are found for CH4, CO, and O3.

Elevated humidity in the stratosphere as a gain factor of ozone depletion in Arctic according to Aura MLS observations

O.E. Bazhenov
V.E. Zuev Institute of Atmospheric Optics of Siberian Branch of the Russian Academy of Science, 1, Academician Zuev square, Tomsk, 634021, Russia
Keywords: стратосфера, температура, влажность, озон, спутниковые данные, аномальные изменения, stratosphere, temperature, humidity, ozone, satellite data, anomalous variations

Abstract >>
Analysis of Aura MLS data showed that the temperature in the stratosphere of Arctic was much lower than normal during the entire period of January-March 2011 in the altitude range 20-35 km. This had led to a considerable spread of polar stratospheric clouds (PSCs) that formed most intensely in periods and at altitudes of minimal temperatures (maximal temperature drops below PSC formation threshold). The main ozone losses were observed in March. They were due to a photochemical release of chlorine that avoided deactivation in view of nitrogen deficit caused by denitrification in the course of frequent dehydration events indicated by oscillations of the altitude of maximal humidity deviation from multiyear norm. Elevated humidity in the stratosphere had increased the threshold temperature of formation of PSCs that persisted until late March; this raised the threshold of chlorine activation and, thereby, delayed the chlorine deactivation, resulting in even higher level of overall ozone losses during March 2011.

Sun effect on surface temperature in the Northern hemisphere

V.A. Tartakovsky, N.N. Cheredko
Institute of Monitoring of Climatic and Ecological Systems of the Siberian Branch of the Russian Academy of Sciences, 634055, Tomsk, 10/3, Academichesky ave
Keywords: солнечная активность, приземная температуры, климат, solar activity, surface air temperature, climate

Abstract >>
Series of temperatures measured at 818 weather stations in the Northern hemisphere and one series of Wolf numbers for the period from 1955 to 2010 are considered. The sun effect on the surface temperature is estimated by the cosine of the angle between the two vectors determined by the series under consideration using the cyclic time. The technique is effective because it provides a broad common frequency band of the series under study. The sun effect has a monotone approximated dependence on the monthly average temperature and reflects the climate geography, including the effect of warm ocean streams. The approach suggested is expedient for applications in the development of observational data analysis, analytical transformations, and climate simulations.

“LOSA-S”- a basic lidar of the Russian segment of CIS-LiNet

Yu.S. Balin1, G.P. Kokhanenko1, M.G. Klemasheva1, I.E. Penner1, S.V. Nasonov1, S.V. Samoilova1, A.P. Chaikovsky2
1V.E. Zuev Institute of Atmospheric Optics of Siberian Branch of the Russian Academy of Science, 1, Academician Zuev square, Tomsk, 634021, Russia
2B.I. Stepanov Institute of Physics, National Academy of Sciences of Belarus, Belarus, 220072, Minsk, Independence Avenue, 68
Keywords: лидар, многоволновое зондирование, линейная и круговая поляризация, аэрозоль, кристаллические облака, lidar, multiwavelength sounding, linear and circular polarization, aerosol, crystal clouds

Abstract >>
Stationary lidar “LOSA-S” is intended for the study of aerosol fields in the boundary layer of the troposphere in the altitude range 0.05-15 km, as well as for the study of crystal clouds using the polarization unit with linear and circular radiation polarization. The scheme of simultaneous observation of elastic and Raman scattering signals when irradiating the medium at wavelengths of 1064, 532, and 355 nm is implemented in the lidar. The lidar is based on a LOTIS-2135 Nd:YAG laser and a Cassegrain receiving specular telescope with a diameter of 300 mm. In addition to the return signals of elastic scattering recorded in the analog mode, the lidar records Raman scattering signals on molecular nitrogen (387 and 607 nm) and water vapor (407 nm) in the photon counting mode. To cover the aforementioned altitude range, two receiving telescopes are used in the lidar for near and far zones; the signals are recorded by the same photodetectors.

Enhancement of pumping efficiency of a CuBr laser by means of modification of the discharge circuit

M.V. Trigub1,2, V.V. Vlasov1, D.V. Shiyanov1, V.B. Sukhanov1, V.O. Troitsky1
1V.E. Zuev Institute of Atmospheric Optics of Siberian Branch of the Russian Academy of Science, 1, Academician Zuev square, Tomsk, 634021, Russia
2National Research Tomsk Polytechnic University, 30, Lenin Avenue, Tomsk, 634050, Russia
Keywords: СuBr-лазер, эффективность возбуждения, энерговклад, импульсный трансформатор, CuBr laser, efficiency, energy input, cable pulse autotransformet

Abstract >>
A technique is suggested for enhancement of the pumping efficiency of a CuBr laser by means of modifications of the discharge circuit with a cable pulse autotransformer. The results of using four different discharge circuits are described. The experiments were carried out under similar operating conditions of the active element and at a constant input power of the pumping source. The output power increases from 14 to 21 W with the use of autotransformer and peaking capacitor. The power increase is a result of a delay between GDT current and pumping voltage and different volume-temporal characteristic of the energy input into a charge. The technique suggested can be used in different applications.