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1.
We describe the methodology and software developed for the numerical analysis of the characteristics of the horizontal and vertical structure of geostrophic currents. We present the results of computation of these characteristics according to the data of the summer survey of the Black Sea carried out as a part of the ComSBlack-92 program. The distinctive features of the space structure of geostrophic currents discovered as a result and the established parameters of their variability may supplement the existing data on the current field in the Black Sea. 相似文献
2.
We analyze the dependence of climatic variations of the location of the upper boundary of the hydrogen-sulphide zone in the
Black Sea on the variations of the sea level and various types of atmospheric circulation (according to A.A. Girs). It is
discovered that the level of correlation between the indicated parameters is high and that the corresponding plots are in
good qualitative agreement. The accumulated results enable us to make an assumption that there exists an 80–100-yr cycle of
variation of all analyzed parameters and that the long-term variations of the location of the upper boundary of the hydrogen-sulphide
zone can be regarded as a manifestation of global climatic variations.
Translated by Peter V. Malyshev and Dmitry V. Malyshev 相似文献
3.
Mountain massif Munku-Sardyk presents the highest mountain range and adjacent Stanovoy ridge highlands of the Eastern Sayan. There is situated modern glaciation site which was the most studied in the course of last 160 years. This periglacial area experienced different periods of cooling and warming in the Holocene and retained traces of the Sartan glaciation of Subboreal (3000–5000 years ago), the Little Ice Age, the evidences of Holocene optimum and general warming last time. The authors examined the variability of activity of modern glaciation and variation of natural conditions of the periglacial zone on climate and on dendrochronological data. Results of larch and Siberian stone pine growth data were revealed at the higher border of forest communities. Analysis of the growth of the “fossil” tree in the Holocene optimum showed that the absolute magnitude of its increment was two times higher than for up-to-date long-lived trees. Identified periods of the Peretolchin glacier retreat in 1900–1965 and 1983–2000 years took place with increased growth of trees and the rate of sedimentation in proglacial lake, and vice versa glacier advance on in 1965–1980 years was accompanied by slowing of tree increments and reduction in sedimentation rate. Since 2000, there has been growth of trees instability associated with a decrease in average monthly summer temperatures. 相似文献
4.
Variability in natural conditions of the periglacial zone of the Munku-Sardyk massif (Eastern Sayan)
Presented are the results from investigating the periglacial zone of the Munku-Sardyk massif in Eastern Sayan. Dendrochronometry data are used in analyzing the cyclicity of natural processes that manifests itself in increment in trees growing in extreme conditions. The analysis revealed secular and intrasecular cycles. A correlation of increments in larch and Siberian stone pine with changes in summer temperatures (the correlation coefficients 0.56 and 0.48, respectively) is observed. For the period of observation of the Peretolchin glacier (1900–2015), the stages of its retreat (1900–1965 and 1983–2000) and advance (1965–1983) were revealed, which influenced the changes in increment in trees and the degree of accumulation of bottom sediments in the proglacial Lake Ekhoi. A comparison of the character of growth of a “fossil” tree in the Holocene optimum with present-day long-lived trees shows a higher sensitivity of the ancient tree (the coefficient 0.43) and a lower sensitivity in present-day trees (0.32 for larch, and 0.26 for Siberian stone pine). Thermochronometry data were used to determine a decrease in air temperature with height in June (an optimal month for increments in trees) by 0.468 °C/100 m. 相似文献
5.
A paper devoted to the transformation of cartographic images based on nontraditional systems of scaling (travel time, transport effort, cost, etc.) describes the results of work to develop a more effective algorithm for such transformations, i.e., one which the authors claim provides for the more accurate determination of “transformed” line lengths than possible with earlier methods. Translated from: Izvestiya AN SSSR, seriya geograficheskaya, 1987, No. 4, pp. 105-111. 相似文献
6.
A conceptual variant for constructing a computer database for the theory of wave processes in the World's Ocean is suggested.
Five basic model components have been singled out, namely, acoustic waves, surface waves, internal waves, gyroscopic waves,
and Rossby waves. The structure of each block is described. The main principle of organizing the databank consists in dividing
the entire variety of wave processes into categories and in generating a hierarchical system of models for each, category,
using the principle of transition from general to partial.
Translated by Vladimir A. Puchkin. 相似文献
7.
8.
We present the first detailed seismic velocity models of the crust and uppermost mantle around the Mirnyi kimberlite field in Yakutia, Siberia. We have digitized vintage seismograms that were acquired in 1981 and 1983 by use of Taiga analogue seismographs along two perpendicular seismic profiles. The 370-km long, northwest striking profile I across the kimberlite pipe was covered by 41 seismographs, which recorded seismic signals from 21 chemical shots along the line, including one off-end shot. The perpendicular, 340-km long profile II across profile I ca. 30 km to the south of the Mirnyi kimberlite field was covered by 45 seismographs, which recorded seismic signals from 22 chemical shots, including four off-end shots. Each shot involved detonation of between 1.5 and 6.0 tons of TNT, distributed in individual charges of 100–200 kg in shallow water (< 2 m deep). The data is of high quality with high signal/noise ratio to the farthest offsets. We present the results from two-dimensional ray tracing, forward modelling.Both velocity models show normal cratonic structure of the ca. 45-km-thick crust with only slight undulation of the Moho. However, relatively small seismic velocity is detected to 25-km depth in a ca. 60-km wide zone around the kimberlite pipe, surrounded by elevated velocity (> 6.3 km/s) in the upper crust. The lower crust has a relatively constant velocity of 6.8–6.9 km/s. It appears relatively unaffected by the presence of the kimberlite field. Extremely large P-wave velocity (> 8.7 km/s) of the sub-Moho mantle is interpreted along profile I, except for a 70-km wide zone with a “normal” Pn velocity of 8.1 km/s below the kimberlite. Profile II mainly shows Pn velocities of 8.0–8.2 km/s, with unusually large velocity (> 8.5 km/s) in two, ca. 100-km wide zones, at its southwestern end, one zone being close to the kimberlite field. The nature of these exceptionally large, sub-Moho mantle velocities is not yet understood. The difference in velocity in the two profile directions indicates anisotropy, but the effect of unusual rock composition, e.g. from a high concentration of garnet, cannot be excluded. 相似文献
9.
Field investigations from different years and remote sensing data have been used in landscape-typological mapping of the regional testing area. The study revealed leading landscape-forming factors. The landscape structure and altitudinal zonality of Eastern Sayan are considered. 相似文献
10.
L. V. Anan’in V. V. Mordvinova M. F. Gots’ M. Kanao V. D. Suvorov G. I. Tat’kov Ts. A. Tubanov 《Doklady Earth Sciences》2009,428(1):1067-1070
Using inversion of SV receiver functions, defined for various directions at each of the three broad-band stations located in the Baikal rift zone,
detailed S velocity models of the crust and upper mantle down to 260 km have been obtained. These models reflect peculiarities of the
velocity structure beneath Baikal depressions and mountains. 相似文献