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Bubukin I. T. Rakut I. V. Agafonov M. I. Yablokov A. A. Pankratov A. L. Gorbunova T. Yu. Gorbunov R. V. 《Astronomy Reports》2021,65(7):598-614
Astronomy Reports - The feasibility of expanding the evaluation parameters was discussed when selecting the “Karadag” test site for the installation of millimeter-wave antennas based on... 相似文献
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F. F. Pankratov A. V. Konoplev A. Makhura O. V. Kats 《Russian Meteorology and Hydrology》2013,38(6):405-413
Mercury is one of the most hazardous heavy metals and the mercury contamination is of serious danger for the Arctic environment. Mercury compounds are rather mobile and can easily migrate both to the water and to the air. Mercury is removed most intensively from the atmosphere during the polar springtime (so-called AMDE effect, i.e., the Atmospheric Mercury Depletion Event). This phenomenon was observed from the beginning of the polar sunrise till the end of the snowmelt, i.e., from April to early June. In 2000–2001, the depletion of atmospheric mercury was discovered in the Antarctic. In 2001, the mercury analyzer was installed at Amderma station located on the Yugor Peninsula, and AMDE cases were registered there during the measurements. The study in the Arctic region demonstrated that the effect of mercury depletion is observed at the rather limited space along the coast of the Arctic seas. The activation of AMDE is associated both with the intensive UV-radiation and with such meteorological parameters as temperature, wind speed and humidity in the surface layer that favors the mercury depletion in the atmosphere. This process is typical for the high latitudes only and is observed during about two-three months from the beginning of the polar sunrise until the end of the snowmelt. 相似文献
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I. V. Florinsky A. N. Pankratov 《International journal of geographical information science》2016,30(12):2506-2528
There are three major mathematical problems in digital terrain analysis: (1) interpolation of digital elevation models (DEMs); (2) DEM generalization and denoising; and (3) computation of morphometric variables through calculating partial derivatives of elevation. Traditionally, these three problems are solved separately by means of procedures implemented in different methods and algorithms. In this article, we present a universal spectral analytical method based on high-order orthogonal expansions using the Chebyshev polynomials of the first kind with the subsequent Fejér summation. The method is intended for the processing of regularly spaced DEMs within a single framework including DEM global approximation, denoising, generalization, as well as calculating the partial derivatives of elevation and local morphometric variables.
The method is exemplified by a portion of the Great Rift Valley and central Kenyan highlands. A DEM of this territory (the matrix 480 × 481 with a grid spacing of 30″) was extracted from the global DEM SRTM30_PLUS. We evaluated various sets of expansion coefficients (up to 7000) to approximate and reconstruct DEMs with and without the Fejér summation. Digital models of horizontal and vertical curvatures were computed using the first and second partial derivatives of elevation derived from the reconstructed DEMs. To evaluate the approximation accuracy, digital models of residuals (differences between the reconstructed DEMs and the initial one) were calculated. The test results demonstrated that the method is characterized by a good performance (i.e., a distinct monotonic convergence of the approximation) and a high speed of data processing. The method can become an effective alternative to common techniques of DEM processing. 相似文献
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S. P. Meacham K. K. Pankratov A. F. Shchepetkin V. V. Zhmur 《Dynamics of Atmospheres and Oceans》1994,21(2-3)
We show that an arbitrarily oriented ellipsoid of uniform potential vorticity, embedded in a background flow described by a quadratic streamfunction, is an exact solution of the quasigeostrophic equations governing motion in a uniformly stratified, unbounded fluid. This type of flow includes plane horizontal shear and strain as well as uniform vertical shear of a unidirectional horizontal flow. We derive ordinary differential equations describing the motion of such a vortex and discuss some aspects of their solutions. We note the existence of steady states (solutions in which the vortex is in equilibrium with the background flow), of periodic solutions near these steady states, of non-periodic trajectories which nervertheless remain in the vicinity of the steady states, and of solutions which represent the shearing out of the vortex by the background flow. We try to use this information to propose partial answers to the question of when a given horizontal or vertical shear flow is likely to destroy a vortex and when a vortex might survive external shear and strain. 相似文献
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A. V. Kuvshinov D. B. Avdeev & O. V. Pankratov 《Geophysical Journal International》1999,137(3):630-650
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M. I. Agafonov G. M. Bubnov I. T. Bubukin V. F. Vdovin R. V. Gorbunov I. I. Zinchenko V. A. Lapchenko V. I. Nosov A. L. Pankratov I. V. Rakut 《Astrophysical Bulletin》2018,73(3):387-392
We present the results of a study of the astroclimate on the Crimean Peninsula in the vicinity of the UNN Kara-Dag radioastronomical station (located at a height of 105 m above sea level). The measurements were taken in semi-automatic mode every 2 minutes from July 22 to September 21, 2017. We consider the variation trends of the atmospheric transparency parameters and plot statistical charts.We obtained statistical data characterizing the astroclimate. Their analysis allows us to forecast the possibility of radioastronomical observations in the millimeter and submillimiter wavelength range transparency windows. 相似文献
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The effect of the oceans and sedimentary cover on global magnetovariational field distribution 总被引：1，自引：0，他引：1
Electromagnetic fields excited by long-period geomagnetic variations were calculated for spherical earth models with the realistic inhomogeneous surface layer. Calculations were also carried out for the model with the double inhomogeneous layer. The modelling results did not display the same level of distortions which had been observed experimentally. The revealed contradiction may be explained by a possible existence of significant inhomogeneities in the earth mantle. 相似文献