S. N. Atutov1,2, V. A. Sorokin1,2 1Institute of Automation and Electrometry, Siberian Branch, Russian Academy of Sciences, pr. Akademika Koptyuga 1, Novosibirsk, 630090 Russia 2Novosibirsk State University, ul. Pirogova 2, Novosibirsk, 630090 Russia
Keywords: лазер, усиление, длина волны 1, 52 мкм, гауссов пучок, модовый состав, laser, gain factor, wavelength of 1.52 μm, Gaussian beam, mode composition
Results of a detailed study of a gas-discharge He-Ne laser with a wavelength of 1.52 μm for telecommunications systems are reported. Some important parameters of the laser are measured, such as the laser beam divergence (M2), the laser power as a function of temperature, laser power stability, noise characteristics of laser radiation, etc. A possibility of laser microminiaturization is mentioned, which is of interest for its application under conditions of intense electromagnetic interference.
I.A. Vasilenko, O.V. Naumenko, K.V. Kalinin, A.D. Bykov
V.E. Zuev Institute of Atmospheric Optics of Siberian Branch of the Russian Academy of Science, 1, Academician Zuev square, Tomsk, 634021, Russia
Keywords: дейтерозамещенные изотопологи водяного пара, колебательно-вращательные спектры, моделирование уровней энергии, эффективный вращательный гамильтониан, deuterium substituted isotopologues of water vapor, vibration-rotation spectra, modeling of the energy levels, the effective rotational Hamiltonian
Subsection: SPECTROSCOPY OF AMBIENT MEDIUM
Modeling of the rotation-vibration energy levels of the first and second triads as well as the first and second hexads of the D218O, HD18O, D217O, and HD17O molecules is performed based of the Watson-type Hamiltonian and the rotation operator written through the Padé-Borel approximants. Rotational, centrifugal distortion and resonance constants as well as mixing coefficients of the resulting wave functions are determined. The scheme of resonance interactions is established. The predictive ability of the effective Hamiltonian parameters obtained is examined in the far extrapolation on rotational quantum numbers.
The method of solving the light scattering problem in the backscattering direction within the framework of physical optics approximation has been considered. The recommendations on preliminary estimate of the contribution geometrical optics beams to the backward direction that can reduce the number of the beams for the calculation has been given. Presented empirical estimates and the guidelines for choosing the optimal step of numerical integration can significantly reduce the resource consumption of the physical optics method. The results of the solutions of the light scattering problem are available free in the form of a data bank of the Mueller matrices.
Results of experiments on controlling the position and length of the filamentation zone of femtosecond laser pulses at atmospheric paths 150 m long using different initial spatial focusing and defocusing are presented. The distribution of filaments along the filamentation zone is found, the dependences of the length of the filamentation zone on the numerical aperture of the beam, its initial radius, and pulse power are measured. Emission spectra of the illumination of targets of various materials, placed in the region of the filament far from the radiation source, are recorded.
Microwave (MW) radiometers are commonly used for monitoring precipitable water vapor (PWV) - the major atmospheric greenhouse gas. The quality and accuracy of the method is assessed in various measuring campaigns. In this study, we intercompare the results of PWV measurements performed with a ground-based MW radiometer RPG-HATPRO (at the Peterhof station of Saint Petersburg State University) and radiosounding data obtained at the Voeykovo station. The dataset includes more than 850 coincident measurements (at the day and at the nighttime) for the period between March 13, 2013 and May 31, 2014. The discrepancy of the both methods is caused by the errors of methods as well as by the spatial inhomogeneity of the fields of PWV in atmosphere. These mismatches can reach tens of percent, which must be taken into account in the intercomparison and validation of different methods for PWV retrieval. The exclusion of cases with significant moisture inhomogeneity allowed the reducing of mean errors and their standard deviation between two sets of measurements up to 3-4% and 12-14%, respectively.
V.E. Pavlov1, S.S. Orlov2, V.V. Pashnev2 1Institute for Water and Environmental Problems of the Siberian Branch of the RAS, 656038, Barnaul, 1, Molodezhnaya str. IWEP SB RAS 2Altai State University, 656015, Barnaul, 61, str. Lenina
Keywords: инфракрасная область спектра, оптические толщи рассеяния и поглощения, яркость неба, асимметрия аэрозольной индикатрисы рассеяния, infrared region, optical depth of scattering and absorption, sky brightness, asymmetry of aerosol scattering indicatrix
In the first part of the paper, we offer a methodological ground for determination of the surface albedo in the near infrared (NIR) region using the observations of the atmosphere spectral transparency and the brightness of day cloudless sky in the Sun almucantar. The contribution of the component describing the processes of light reflection into the brightness at different angular distances from the Sun is analyzed. The effect of aerosol absorption on brightness components used to determine the albedo is estimated. The effect of the zenith angle of the Sun and the elongation of aerosol scattering indicatrix on the final albedo calculation is revealed.
The article is devoted to the methodology of obtaining the spatial distributions of respirable fractions of aerosol in the atmosphere from multifrequency lidar sounding data without the use of additional optical and microphysical aerosol parameters on the path under study. For this purpose, it has been suggested to replace the spectral values of the aerosol extinction coefficient involved in lidar equations by the linearly independent parameters of their approximation, and retrieve the spatial distributions of these parameters from the numerical solution of the system of equations created from all spectral-temporal readings of lidar signals. As a result, the number of unknowns in the system of equations, which are solved, is significantly reduced, and its matrix becomes well-conditioned that can be used to select physically reasonable values of backscatter-extinction aerosol ratio at the operating lidar wavelengths. The assumption that there are two segments with the similar profiles of aerosol extinctions coefficients is used to determine the calibration constants of lidar. The algorithm for searching such segments from the spectral-temporal structure of lidar signal is suggested. The inverse problem of aerosol light scattering is solved on the basis of stable regression relations between the concentrations of respirable aerosol fractions and approximation parameters of its extinction spectrum. The tolerance of the technique developed to the calibration errors and the spatial variations in backscatter-extinction aerosol ratio is shown from numerical experiment on laser sounding of aerosol.
Laser fluorescence method of plant state detection is considered. Laboratory setup is described and analysis of plant fluorescence spectra excited at a wavelength of 532 nm are presented. It is shown that the measurement small series average of the fluorescence intensity ratio R at wavelengths of 685 and 740 nm is marked by high stability for different samples of a plant. Sum of confidential intervals of ratio R (for confidential probability 95%) in most cases is no more than difference of mean values of the ratio R for normal and stress states caused by various reasons.
A.V. Lavrinenko
V.E. Zuev Institute of Atmospheric Optics of Siberian Branch of the Russian Academy of Science, 1, Academician Zuev square, Tomsk, 634055, Russia
Keywords: двумерная динамико-стохастическая модель, алгоритм фильтра Калмана, связанные процессы, сверхкраткосрочный прогноз, two-dimensional dynamical-stochastic model, Kalman filter algorithm, related processes, short-term forecast
The two-dimensional dynamic-stochastic model based on the Kalman filter algorithm and method of its application for supershort-term, with a lead of 1 to 6 hours, forecast of meteorological fields in the case of related processes is considered. The results of the statistical evaluation of joint forecasting of fields of temperature and pressure measurements at meteorological stations Novosibirsk (code 29634) and Tomsk (code 29430) for 2014, carried out every 0.5 and 3 hours, respectively, are discussed. The comparison of the quality of the prediction of meteorological fields for the case-related processes and in the case of prediction of each field individually are carried out.
