The results of the study of meteorological series of observations using the methodology of singular spectral analysis are presented. High-frequency measurements of ultrasonic weather stations located at the testing ground of IMKES SO RAS were used as data. The processing of meteorological data included two complementary stages - decomposition and reconstruction. At the decomposition stage, the meteorological series of observations were transformed into a multidimensional series by forming a trajectory matrix and its decomposition into singular vectors - sets of additive components. At the reconstruction stage, various groups of components formed reconstructed rows, interpreted as trend, harmonic and noise components of the meteorological series structure.
The work presents the results of the analysis of Eurasia climate system structure change over the period of modern climate warming. The authors developed the algorithm based on analytic signal theory, allowing grouping geophysical signals over various spatial and temporal scales. Surface temperature was selected as an integrated indicator of climate change. Climate clusters were separated based by the level of similarity in temperature oscillations annual variation phase change on Eurasia stations. Periods corresponding to major trends in global temperature dynamics were considered. We have revealed that during global warming, since 1976, there is a restructuring in regional fields patterns taking place, level of congruence of temperature oscillations changes, many stations of previously northern classes migrate to southern classes. Classification results confirmed that Russian Arctic and Subarctic are the regions that are most sensitive to global temperature changes.
The paper researches Northern hemisphere surface temperature field structure based on the data of 818 meteorological stations for different time frames. Surface temperature is an integrated indicator of the global and regional climate change. Authors classified the stations by the degree of congruence in their multi-year temperature dynamics at various yearly intervals, corresponding to global climate trends. Temperature observational series were interpreted as phase modulated oscillations. The suggested classification is based on the hypothesis of geographical dependence in temperature signal phase modulation specifics. Congruence, namely temperature oscillation phasing in particular regions serves as a criteria for classification. The totality of climate-regulating influences on climate system forms a complex kind of phase modulation, which is though in some correspondence to those disturbances. We believe, that changes in synchronization modes of climatic and natural processes, is consequent to system transition into a new quality. The paper shows that with a global temperature growth regional temperature fields restructure and degree of congruence in temperature dynamics changes. Those changes are not uniform over different regions of the hemisphere. Temperature field congruence tends to decrease. The search for synchronization in non-linear chaotic systems, sensitive to initial conditions, might become a promising way of predicting models optimization.
The paper describes a software complex for designing a horizontally-scalable distributed information-calculation platform with loosely coupled calculation nodes. The platform is intended information support for parallel processing of multi-dimensional data and large time series. The technological scheme for platform design and deployment includes a cluster of processing nodes and a cluster of storage nodes which provide their services if requested by researcher. The main node of each cluster is the command center. Storage management center coordinates functional data processing according to instructions received from researchers. Applications are designed as jnlp-files which ensures their functionality on research terminals.
The paper describes the analysis of correlation dependences between meteorological parameters for a series of observations obtained at station with a synoptic index of 29430. It was shown that the parameters with strong correlation dependences have virtually unchanging correlation coefficient for every time scale of the sample. In the case of meteorological parameters with weak correlation coefficient, there are non-significant jumps in the correlation coefficient values. For meteorological parameters with moderate correlation coefficient, increasing the sample time scale leads to stabilization of correlation coefficient values.
The authors developed the algorithm based on analytic signal theory, allowing grouping geophysical signals over various spatial and temporal scales. Surface temperature was selected as an integrated indicator of climate change. Algorithm can distinguish the climatic structures where multi-year temperature oscillations are congruent. To accomplish that, the information on temperature series amplitude temporal changes was used. Computing technology developed was applied to the data from 818 northern hemisphere meteorological stations over the period of 1955-2010. The classification for three correlation thresholds was obtained. Distinguished structures have strict geographical differentiation and defined by the highest synchronism level of temperature oscillations. Stations closest to each other spatially demonstrate the highest strength of relationship to typical class envelope.
This article presents the method of logging the earth’s natural pulsed electromagnetic noises for mapping anomalies of the earth's crust stress-strain deformed state. Methods for identifying small-scale space-time variations of the earth's natural electromagnetic field at global and regional scale are proposed. The paper describes an automated system for controlling geodynamic processes based on the systematization and processing of the earth’s natural pulsed electromagnetic noises recorded by ground-based multichannel geophysical loggers. The developed software downloads data obtained by registrars to the system database, allows to remotely configure the system hardware, allows to identify and authenticate the groups of researchers. It also provides researchers with the means to sample the required data and to process it mathematically in order to monitor the geomagnetic situation and identify dangerous geological processes, provides visualization of processing results and is capable of exporting specific data for further analysis in other software environments.
Basing upon example of Wolf number series synchronous analysis and temperature values from 818 meteorological stations in the Northern hemisphere (1955-2010) it is shown that, for studied series, the components that differ by distinctive features matching and mismatching display extreme properties. The histograms of the primary temperature series coincide with histograms of their components except for the range of ± 3°С. Second initial moments of Wolf numbers’ components match climate geography and end up in two zones with width and difference in-between equal to about a third of possible change amount. Correlating synchronization features of geosphere processes initiated by external influence, with the use of physical-geographical hierarchy, allows to solve the classification task for temperature field; i.e. it allows to decompose initial sets into subsets containing strongly connected components. There were no discrepancies with known ideas about climate processes.
This article justifies the usage of natural pulsed electromagnetic Earth’s noises logging method for mapping anomalies of strain-stress state of Earth’s crust. The methods and technologies for gathering, processing and systematization of data gathered by ground multi-channel geophysical loggers for monitoring geomagnetic situation have been experimentally tested, and software had been developed. The data was consolidated in a network storage and can be accessed without using any specialized client software. The article proposes ways to distinguish global and regional small-scale time-space variations of Earth’s natural electromagnetic field. For research purposes, the software provides a way to export data for any given period of time for any loggers and displays measurement data charts for selected set of stations.
This paper reviews the concept of designing an open, horizontally scalable distributed information and computing environment, presented in the form of decentralized resource architecture (including computing nodes, storage nodes, communication channels) with decentralized computations and data management. The distributed infrastructure divided into two main components, the computational cluster and the storage cluster. Management of the cluster assigned to specialized frameworks – the infrastructure manager, network manager, computing manager, storage manager, authorization manager, web manager, upload manager. This paper shows the results of a practical study of the processed meteorological parameters obtained with standard ultrasonic weather station on the developed information-computational environment.
The possibility of comparing the climatic data of various years with using rank distributions is considered in this paper. As a climatic data, the annual variation of temperature on the spatial areas of meteorological observations with high variability in average temperatures is considered. The results of clustering of the monthly average temperatures values by means of a recurrent neural network were used as the basis of comparing. For a given space of weather observations the rank distribution of the clusters cardinality identified for each year of observation, is being constructed. The resulting rank distributions allow you to compare the spatial temperature distributions of various years. An experimental comparison for rank distributions of the annual variation of monthly average temperatures has confirmed the presence of scatter for various years, associated with different spatio-temporal distribution of temperature. An experimental comparison of rank distributions revealed a difference in the integral annual variation of monthly average temperatures of various years for the Northern Hemisphere.
The approach allows to organize distributed storage of large amounts of diverse data in order to further their parallel processing in high performance cluster systems for problems of climatic processes analysis and forecasting. For different classes of data was used the practice of using meta descriptions - like formalism associated with certain categories of resources. Development of a metadata component was made based on an analysis of data of surface meteorological observations, atmosphere vertical sounding, atmosphere wind sounding, weather radar observing, observations from satellites and others. A common set of metadata components was formed for their general description. The structure and content of the main components of a generalized meta descriptions are presented in detail on the example of reporting meteorological observations from land and sea stations.
During processing of fringes interferogram, a missing data of the interferogram fringes in area of the aperture edge make
difficulties for positioning of the equal-phase lines. It results in mistakes of the phase surface recovering at boundary of
the interferogram area. Inaccuracy of building of the equal-phase lines in the marginal area directly connected with the
width of the interference fringes. In this paper the method of interference fringe tracing in the marginal interferogram
area is proposed, the influence of extrapolation of the equal-phase lines on the accuracy of the phase recovering is
investigated, results of closed numerical experiments on the interferogram processing are presented.
The accuracy of an interference measurement experiment depends on the conditions of the fringe pattern formation. This
work is a study into the influence of the Gaussian inhomogeneity of a laser beam on the error of the wavefront
reconstruction. The illuminating laser beam is represented as a Gaussian model. It has been demonstrated that the
efficient size of the laser beam influences the measurement error, and this effect is the most pronounced in evaluation of
the interferograms with a small number of fringes, especially during high-precision measurements.
In optical radar, communication, and energy transfer one frequently encounters the problem of transportating optical radiation energy to an object located in a randomly inhomogeneous medium. The scattering by the refractive index inhomogeneities of such a medium reduces the average intensity in the axial part of light beam and generates fluctuations of the intensity, so that the result is a considerable deterioration of the energy characteristics of systems operating in such media. The amplitude and phase fluctuations of Gaussian beam, propagated through the turbulent atmosphere, are not spatially homogeneous in a transversal beam section. Here we introduce an estimation criterion for beam computed for some different values of aperture/beam diameter ratio. The numerical simulations of beam propagation through the random-inhomogeneous media were performed using modified splitting method. The results of numerical experiments as well as the behavior of proposed criterion are discussed.
The paper presents an algorithm for analysis of the fringe interferogram, registered by the matrix CCD-camera. It is new version of classical method of extremal lines. After an interferogram preprocessing, the set of reference section of interferogram is processed to find of coordinates of extremal points of interference fringes. Then, beginning at these points, along each of fringes, extremal lines are traced. Direction of each extremal line is corrected using of correlation comparison of local sample of the interference fringe with adaptive adjusting model of this fringe during tracing. Coordinates of extremal lines serves nodes of interpolation of the phase for building of the phase surface within the whole aperture where interferogram is given.
To control the optical parts of a wide range, it is suggested to use an interferometer with aligned branches, which includes a series of accessory lenses. To control large-dimension parts, a spherical mirror with a compensator is used as a power component. The paper presents the main specifications and schematic diagrams of the focusing objectives as well as the variants of the zoom-lens schematics and their characteristics intended to test the large-dimension parts of plane, convex and concave shapes.
The accuracy of a high-precision interferometric experiment depends on both instrument errors and errors connected with processing the interferograms. Both types of errors can be minimized by an optimum adjustment of the functions of the basic unit of the system. The paper addresses the issue of error optimization using different adaptive systems within a laser interferometer design.
A possibility of live fringe-pattern phase restorative by means of estimates of separate lines or sections of interferogram is submitted. It is possible if the phase is accepted the monotonous function in each section of interferogram. Thus, realization of on-line interferogram demodulation is possible and, besides, the fringe-pattern vibration effect is reduced.
To solve some astronomical problems and the problems of atmospheric sounding, it is necessary to apply high-quality optical antennas because the quanlity of the optics determines the error at the parameter measuring. An intrinsic feature of the process of optical pieces manufacturing is the control of the quality of their shape at the production. Interferometry is one of the most precise methods for optical testing. The main difficulties in the control of the shape of optical surfaces are connected to the compensation of the aberrations of optical systems used to form the preset wavefront on the surface of the piece under control. When the aberrations are present in the object branch, the deformation of the interferometric fringes occurs even in case of a complete correspondence of the wavefronts of the object wave and the comparison wave. The appearance of the residual aberration is conditioned by the error of the manufacture of the elements of the illuminating branches, the remainder of the calculation and adjustment error. It is impossible to completely compensate for the residual aberration by introducing stringent manufacture and adjustment tolerances. That is why an optical system that forms the reference wavefront should possess a limited minimum value of the residual wave aberration. It is suggested to use a versatile adaptive mirror based on a bimorphed piezoelectric element as technical means for residual aberration correction. By selecting suitable controlling stresses, one may reach a rather good simulation of the geometric and wave aberrations to decrease the value of the residual aberration of the illuminating branch of the interferometer, thus increasing the precision of the interferometric control. The experimental results in the design of a real interferometer are given and discussed.
A possibility of restoration of live fringe-pattern phase by means of estimation of separate sections of interferogram is considered. It is possible if the phase is a monotonous function in any section of interferogram. Doing so, on-line interferogram demodulation is realized and, besides, the fringe-pattern vibration effect is reduced.
Interferometry is one of the most precise methods for optical testing. Nevertheless, interferometers are not ideal, they contain internal residual aberrations, and the methods for interferograms analysis are subjected to noise effect and depend on the interferogram parameters. The practice of the modem interferometry faces the following contradictions: on the one hand, up-to-date software allows processing an interferogram at an error of A1200-A1500, on the other hand, a really reached error of an interferometer does not exceed ?/50. Well-known interferometer designs applied in optical testing have been analyzed. A design of interferometer containing aligned branches was chosen. It is less sensitive to vibrations and more compact, allowing one to test surfaces with a larger numerical aperture. This is design of an interferometer, whose principal element represents an aplanatic lens, low sensitive to decentering. The interferometer is stable when defocusing the recording system. At the restoration of the wavefront from the object tested, samples of interferograms were used differing in the number and orientation of the fringes, which allows one to improve the test precision. This occurs due to the shift of the object signal in the area of spatial frequencies. In this case the estimate variance of the wavefront decreases approximately proportionally to the amount of sampling of interferograms. The present paper analyses the factors that influence the precision of testing the shape of the piece surface, the possibility of design and programmed algorithmic correction of the factors influencing the testing precision. An interferometer where such engineering means of correction would be implemented could be called 'an ideal interferometer'
The state-of-the-art in definition of the amplitude and phase of signals as applied to analysis of fringe patterns like interferogram is discussed. The problem of both theoretical and practical significance, namely, the conditions for existence of two-band spectrum of real signals, are considered. Some constructive results are presented.
The purpose of this investigation is the study of the process of the optical vortices pair arising from the nonzero intensity minimum. We propose and analyze a local polynomial model of optical vortex pair creation. The optical vortices arise around zero points of intensity, which lie on the zero-crossing lines of real and imaginary parts of wave field on real-plane. The appearance of the optical vortices is an indication of transition of wave into a new more complex state. Numerous theoretical and experimental papers are devoted to the investigation of such objects; the structure of isolated vortex and its statistical properties are studied there usually. The coordinates of real-plane zero points are located in the recovery problems of optical wave fields. However, the location of real-plane points is impossible for experimental data because of discretization and quantization of signals. Therefore an analytical model is necessary to study the creation and annihilation of the optical vortex pair and other spatial points at wave propagation.
Method of light-wave measurement for adaptive optical systems, which may be useful in conditions of the strong fluctuations, is considered. It is proposed to measure the light-wave phase on a closed trajectory, lying into the aperture where the wave intensity is significant, and to locate boundaries of the probably optical vortices, within which the intensity is close to zero. Operations and schematics of two novel devices are described, namely Hartmann Scanning Sensor and Directional Shearing Interferometer.
The optical vortices arise around zero points of intensity, which lie on the zero-crossing lines of real and imaginary parts of wave field on real-plane. The appearance of the optical vortices is an indication of transition of wave into a new more complex state. Numerous theoretical and experimental papers are devoted to the investigation of such objects; the points are located in the recovery problems of optical wave fields. However, the localization of the real- plane zero points is impossible for experimental data because of discretization and quantization of signals. Therefore an analytical model is necessary to study the creation and the annihilation of the opticla vortex pair and other special points at wave propagation. The wave field in the investigated area is approximated by irreducible second order polynomial of two variable for conservation of local convexity of zero-crossing lines. It has been found analytically and numerically that the local minima of intensity precede the zero, that is complicated point without vortex and which, during wave evolution, bifurcate in two real-plane zero points separated by the saddle point.
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.
A physical phenomenon of wave propagation has certain logarithmic threshold of complexity above which the conventional description of wave process is inadequate. From this reason the real-place zeros of light wave are examined in the present paper. The probability of the real-plane zero occurrence is calculated by the numerical simulation of the light-wave propagation in an inhomogeneous medium. The functional relationship between the phase and the amplitude logarithm of the wave function near its real zero point has been found. This result takes the form of the dispersion relation, derived analytically and supported by numerical experiments.
The Gabor analytic signal is constructed by means of the Hilbert transform. This linear operator gives the single-valued determination of the envelope and phase of a 1D signal with the support from infinity to infinity. But the wave field has four arguments and the interferogram is a 2D function. Moreover, these functions can be measured only in a restricted domain. These problems are discussed in this paper. In addition, the errors estimation of phase recovering are considered. The results of numerical experiments on the interferogram inversion are given.
In the paper the two systems developed at the Institute of Atmospheric Optics (Tomsk) are considered. The systems are intended for monitoring of wavefront parameters and phase control. These two systems supplement one another: one of them operates in the IR-range (8 - 12 micrometers ), the second one operates in the visible wavelength range. The second system is a multi-function original computer system for a contact less control of optical surfaces and a detailed analysis of laser beam parameters. It is intended for: (1) the investigation of shapes and quality of optical surfaces by the interferential method of control; (2) the reconstruction of the wavefront of laser radiation based on an interferogram; (3) modeling of interferograms with preset parameters; (4) the analysis of spatial characteristics of continuous and pulse laser beams.
In this paper, the two systems developed at the Institute of Atmospheric Optics, USSR, are considered. The systems are intended for monitoring wave front parameters and phase control. The two systems supplement one another: one of them operates in the IR-range while the second one functions in the visible wavelength range.