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In an effort to stabilize the declining level of the Caspian Sea, it has been proposed that evaporation from the water surface be reduced by decreasing the size of the sea through construction of a dam in the northern portion. Data on the geology and hydrology of the Caspian Sea bed suggest that the construction of a dam might have undesirable consequences not only for the northern fisheries basin but for the sea as a whole. The findings are based on the presence of salt domes on the bottom of the northern Caspian Sea. An influx of highly mineralized subsurface waters along faults associated with the salt domes as well as leaching of salt from the structures themselves may threaten to raise the salinity of the northern fisheries basin to intolerable magnitudes. The presence of a man-made dam, in the author's view, would also interfere with the natural circulation of water, threatening contamination of deeper layers of the Caspian Sea with hydrogen sulfide, as has happened in the case of the Black Sea. [For a discussion of the Caspian Sea problem, see Soviet Geography, November 1972.] 相似文献
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D. M. Kudritskiy 《Eurasian Geography and Economics》2013,54(4):265-272
Differences in available data on the area of the Caspian Sea are analyzed, and an effort is made to explain them. The differences are particularly pronounced in the shallower northern portion of the sea, where the drop of the sea level over the years has produced more significant changes in shoreline configuration. Greater use of space imagery is urged in determining changes in shoreline configuration, and the setting of “geographical standards” is proposed to avoid continuing confusion in published data. The technical problem of calculating the physical water area, including surface roughness produced by wave motion, is discussed. 相似文献
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A second paper devoted to problems of predicting the future level of the Caspian Sea attempts, as did the first, to discount overly simplistic explanations for its nearly century-long decline and recent slight rise. Long-term climatic changes within the drainage basin of the Caspian and the resultant change in discharge of tributary rivers are proposed as the basic mechanism controlling sea level fluctuations and not, as argued in the popular press, tectonic movements, groundwater discharge variations, or the damming of the Kara-Bogaz-Gol. Various models for predicting future levels are compared, although no specific forecasts are made (translated by Andrew R. Bond). 相似文献
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O. K. Leont'yev 《Eurasian Geography and Economics》2013,54(6):608-616
The first of two papers on the problem of forecasting the level of the Caspian Sea evaluates factors widely believed to have been responsible for its lowering during much of the present century (including tectonic movements, climatic cycles, human activity). It concludes that previous forecasts have been inaccurate because of the failure to adequately model the complexity of processes involved, specifically the internal mechanisms of “self-regulation” of water levels. Continuation of the recent slight rise in the Caspian's level is predicted at least into the early 1990s (translated by Andrew R. Bond). 相似文献
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The authors, questioning the implications for the Caspian of a conventional model of shoreline dynamics on a flat, sandy coast upon a rise in sea level, present the findings of field observations made along the Dagestan shore during the period (post-1977) of the recent rise of the Caspian Sea level. They argue that changes in coastal morphology have varied largely according to the steepness of the offshore slope and, in general, sharply accelerated erosion was observed only on more steeply sloping sections of coast and in areas previously protected by rock benches (translated by Jay K. Mitchell; PlanEcon, Inc.; Washington, DC 20005). 相似文献
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Martin Ira Glassner 《The Canadian geographer》1993,37(3):271-279
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In view of the declining inflow into the Aral Sea, alternative proposals are advanced to save this inland sea by reducing its area as well as its salinity levels. The proposals involve the closing off of some portions of the sea, notably the Little Aral in the northeast and the Western Aral, from the large shallow eastern portion. Some portions of this fragmented sea would then be treated as active bodies of water with a throughflow regime, discharging surplus waters of high salinity into other portions, which would be allowed to become salt marshes. Various combinations of active water areas and residual water areas are examined, and possible trends in waterlevel and salinity are projected to the middle of the 21st century. 相似文献
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A large body of empirical data on the dynamics of local travel in the USSR is surveyed to illustrate the influence of commuter movement on the formation and spatial interaction of settlement systems. Correlations are established between commuting patterns and the population levels of cities of different size cateogries. (Translated by Marcia Levenson, University of California, Berkeley, CA 94720.) 相似文献
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The red ink on four fragments of the Dead Sea Scrolls was analysed by X-ray fluorescence and X-ray diffraction. The red pigment was identified as mercury sulfide (HgS), cinnabar. The significant archaeological and historical aspects of this finding are discussed. 相似文献
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The authors concentrate on four aspects of environmental alteration of the Sea of Azov. First, they trace the Azov's problems back to Soviet resource-use conflicts. Second, they present several examples of anthropogenically induced environmental disruption of the Azov's ecosystem. Third, modeling is utilized to project possible future salinity conditions within the Azov. Fourth, in their attempt to evaluate the various ameliorative efforts that have been made or are being proposed, they challenge the overall ecologic-economic effectiveness of the proposed dam across the Kerch' Strait designed to regulate the salinity of the Azov. Finally, they conclude it is unlikely that the Azov ever will be returned to its previous “natural” condition. This article should be read in conjunction with Pecherin's article also in this issue of Soviet Geography. (Illustrations by Elinore Mathews, University of Washington, Seattle.) 相似文献
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A. S. Kes' 《Eurasian Geography and Economics》2013,54(2):104-113
A specialist in loess geomorphology and arid-zone hydrology distinguishes three categories of factors accounting for waterlevel changes in the Aral Sea. She judges the most significant to be changes in inflow resulting from changes in the course of the Amudarya, the more important of the two tributary streams. The Amudarya at various times emptied into the Sarykamysh depression, southwest of the Aral Sea, giving rise to a flow of water through the now dry Uzboy channel to the Caspian Sea. Climatic change, involving alternations of wet and dry cycles, is said to have accounted for only minor water level fluctuations, of the order of 4 to 6 m, against the background of the major fluctuations produced by the Amudarya course migrations. Human activity, notably irrigation, is regarded as having become significant only in modern times as a result of an expansion of irrigation works. The present abrupt decline in the Aral waterlevel (6 m from 1960 to 1977, including 2 m in the last three years) is attributed to the combination of a dry climatic cycle and greatly increased use of water for irrigation. 相似文献
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USING A COMPOSED ERROR MODEL TO ESTIMATE THE FRICTIONAL AND EXCESS-SUPPLY COMPONENTS OF UNEMPLOYMENT
ABSTRACT We present in this paper a plausible and simple method of estimating the two components (frictional and excess supply) of unemployment. This approach uses a stochastic model whose error term is composed of two elements–the usual two-sided error and a one-sided error. Our method has several strengths. First, we are able to explicitly model the universally held view that there is a nonzero lower bound on unemployment. Second, we can easily determine whether each region's unemployment rate is caused primarily by excess supply or frictional forces. We illustrate our technique on a data set comprised of all 50 states over the period 1960-1979. Finally, estimation of the frictional rates of unemployment allows us to analyze, in the last part of the paper, the underlying economic and demographic determinants of differences in frictional unemployment rates across states and over time. 相似文献
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V. A. Kuchkin 《Eurasian Geography and Economics》2013,54(5):330-343
The main stages in the territorial formation of the principalities of Northeastern Rus' in the second half of the 13th century are examined. The influence upon this process of the Tatar-Mongol invasion, and the creation of the conditions for the rise of Moscow, Tver', Kostroma, and Gorodets as possible future centers for the unification of the Russian lands, are demonstrated. (The translation was prepared by James R. Gibson of York University, Toronto.) 相似文献
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Inelastic response spectra are estimated for elasto-plastic SDOF systems subjected to strong earthquake ground motions by applying the strength reduction factors determined for a simple pulse to the elastic response spectrum of the ground motion. This approach relies upon similarities in the strength reduction factors computed for earthquake ground motions and for short duration pulses. The accuracy of the estimated inelastic spectra obtained using 24 simple pulse waveforms is assessed in order to identify subsets of just several pulse waveforms that are suited for this purpose. Based upon the ground motions and pulses investigated, this approach appears to be equally applicable to short and long duration ground motions and those having near-fault forward directivity features. 相似文献
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V. M. Borovskiy 《Eurasian Geography and Economics》2013,54(2):63-77
The author examines the problem of the present state of the environment in the desert irrigation districts of southern Kazakhstan and Central Asia. A drop of the level of the Aral Sea and the formation of new land on the exposed seabed, the desiccation and desertification of the Amudarya and Syrdarya deltas caused by an intensification of agriculture have been proceeding against the background of a series of dry years. Irreversible environmental changes are having a negative impact on the socioeconomic conditions of the Aral region. The author, basing himself on the results of scientific investigations related to the Aral Sea problem, proposes a number of measures designed to moderate this negative impact. 相似文献
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