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1.
Current Variations in the Wind Speed Vector and the Rate of Evaporation from the Caspian Sea Surface
Regularities in the rearrangement of the surface atmospheric circulation in the Caspian Sea region are studied. It is found that during the current rise in the Caspian Sea level, a statistically significant decrease in the wind speed modulus occurred (mainly in autumn and winter winds of zonal directions). This caused a decrease in the rate of evaporation in the region. The results of this study testify to a need for developing a deterministic model of current variations in the Caspian Sea water regime at varying global and regional climate. 相似文献
2.
Numerical Simulation of the Caspian Sea Circulation Using the Marine and Atmospheric Research System
The Marine and Atmospheric Research System (MARS) for the Caspian Sea meteorological characteristics is presented, which is implemented in Zubov State Oceanographic Institute. It includes computation of the atmospheric forcing with the Weather Research and Forecasting model, as well as computation of currents, sea level, temperature, salinity and sea ice with the Institute of Numerical Mathematics Ocean Model and the computation of wind wave parameters using the Russian wind-wave model. The results are presented on verification of the hydrometeocharacteristics simulated with the MARS for the Caspian Sea. As well, the retrospective simulation of the thermohydrodynamic characteristics in this basin is performed with MARS for the ice-free period 2003–2013. The important features of the Caspian Sea circulation are shown. 相似文献
3.
V. N. Mikhailov D. V. Magritsky V. I. Kravtsova M. V. Mikhailova M. V. Isupova 《Water Resources》2012,39(1):11-43
Regularities in the response of the mouths of major rivers, flowing into the Caspian Sea, to large-scale variations in its
level and river water runoff and sediment yield are considered. Changes in the morphological structure and hydrological regime
of the Volga, Terek, Sulak, Ural, and Kura mouths have been analyzed in both geological past and separately for three modern
periods: a considerable drop in Caspian Sea level before 1978, its abrupt rise in 1978–1995, and a relative stabilization
in the subsequent years. Specific features were identified in the hydrological-morphological processes in different mouths,
caused by the differences in river sediment yields, and the slopes of delta surface and mouth nearshore beds. Some theoretical
and methodological approaches were verified in the analysis and evaluation of the processes under consideration. The obtained
results of studies of the mouths of rivers flowing into the Caspian Sea can be regarded as examples and analogues in the assessment
of processes, which take place at the mouths of other Russian and world rivers at present and can take place in the future
under anticipated natural and anthropogenic variations in sea level and river runoff. 相似文献
4.
Nonlinear mechanisms of long-term variations in the Caspian Sea level are described. It is shown that with account taken of the dependence of the evaporation depth from the Volga basin surface on soil moisture content and the dependence of the evaporation depth from the sea surface on its level, we obtain a fundamentally new (chaotic) oscillation mechanism with several attraction levels. The stochastic differential equations describing the water budget of the sea basin and the sea proper and the respective solutions of the Fokker–Planck–Kolmogorov equation are shown to have stationary bimodal density of the level probability. The random process, characterizing the sea level variations at a nonlinear dependence between the evaporation rate and the level is found to be non-Gaussian. Noise-induced transitions, caused by nonlinear evaporation processes are described. A new nonlinear stochastic theory describing the Caspian Sea level variations and based on predicted physical effects is suggested. 相似文献
5.
A new thermophysical mechanism of the Caspian Sea level variations is proposed. The mechanism incorporates the effect exerted on the dynamics of the water budget of the Caspian Sea by the nonlinear dependence of the evaporation rate on the moistening of the basin. 相似文献
6.
The Caspian Sea (CS), the world's largest inland sea, may also be considered as large-scale limnic system. Due to strong fluctuations of its water level during the 20th century and the flooding of vast areas in a highly vulnerable coastal zone, economic and environmental risk potentials have to be considered. Since the major water input into the CS is attributed to the Volga river, the understanding of its long-term flow process is necessary for an appropriate risk assessment for the CS and its coastal area. Therefore, a top-down approach based on statistical analyses of long-term Volga flow series is pursued. For the series of annual mean flow (MQ) of the Volga river basin during the 20th century, a complex oscillation pattern was identified. Analyses for multiple gauges in the Volga river basin and Eurasian reference basins revealed that this oscillation pattern resulted from the superposition of oscillations with periods of ∼30 years (MQ) in the western part of the Volga river basin, and ∼14 years (flow volume of snowmelt events) and ∼20 years (flow volume of summer and autumn) in the eastern part of the Volga river basin (Kama river basin). Almost synchronous minima or maxima of these oscillations occurred just in the periods of substantial changes of the Caspian Sea level (CSL). It can thus be assumed that the described mechanism is fundamental for an understanding of the CSL development during the 20th century. Regarding the global climate change, it is still difficult to predict reliably the development of the CSL for the 21st century. Consequently, we suggest an ongoing, interdisciplinary research co-operation among climatology, hydrology, hydraulics, ecology and spatial data management. 相似文献
7.
The results of studying the distribution of hydrotroilite (a product of bacterial sulfate-reduction) in deep-water bottom sediments in the Southern and Middle Caspian Sea are considered and its relationships with paleoclimatic and paleohydrological processes in the sea basin are analyzed. 相似文献
8.
Elision and infiltration groundwater of the Northern Caspian basin are described. It is shown that a zone of elision brines with a high formation pressure exists under the Caspian Sea. These brines are shown to penetrate from below the Caspian Sea into the underground beds, carry fluids, and facilitate the formation of hydrocarbon fields. 相似文献
9.
The regularities in present-day variations in the wind speed vector are examined at 18 stations along the section from Kola Peninsula to the Caspian Sea. Data on long-term variations in the major climate-forming factors and climatic parameters are generalized. The statistically significant tendency toward a considerable decline in the wind speed with a maximum module and the most frequent wind speeds of zonal, mostly western, directions (this tendency has been revealed earlier for the eastern coast of the middle and southern Caspian Sea) was found to hold for the greater part of the European Russia. Possible causes of present-day climate changes and their manifestations at the regional level are analyzed. A possible mechanism of present-day climate changes is proposed 相似文献
10.
Present changes in the regime and structure of mouths of rivers, which empty into the Caspian Sea, are discussed. The similarities and differences of these processes at the mouths of different rivers of the Caspian Region were revealed. Assessment was made of the impact of changes in river water runoff and sediment load and in the Caspian Sea level as well as the nearshore zone relief and local hydraulic engineering activities on the processes under study. Anomalous features of the processes occurring at the mouths of the Volga and Terek rivers were revealed and explained. Hydrological and morphological processes typical of the present mouths of the rivers of Ural, Sulak, and Kura were revealed; these processes could be accepted as universal and possible analogs in assessing the expected changes at the mouths of other rivers in Russia and the world in the XXI century. 相似文献
11.
The problem of assessment of sea level rise impact on the hydrological regime and morphological structure of river deltas
is discussed. Studies of the response of river deltas, which are among the most vulnerable natural objects, to the sea level
rise has become urgent because of the global climate warming and the associated acceleration of the World Ocean level rise.
Methods are described that can be used for the analysis, calculation, and prediction of sea level rise impact on submergence
of deltas, propagation of backwater from the sea tides, surges, and salt seawater intrusion. Special emphasis is given to
channel processes in delta branches, which accompany sea level rise, as well as to delta coastline erosion and flow redistribution
among branches. In the course of research, due consideration was taken of the experience gained in studying the response of
river deltas on the Caspian Sea coasts to the recent considerable level rise in this water body. 相似文献
12.
Ratkovich D. Ya. Vyruchalkina T. Yu. Nikonova R. E. Solomonova I. V. 《Water Resources》2002,29(5):485-496
The results of probabilistic analysis of data on setup level variations collected during long-term observations at all gages along the Caspian Sea coast are discussed. A procedure for evaluating low-probability sea level extremes is proposed. Estimates are given for the probabilities of outstanding setups in the Caspian Sea and the Sea of Azov. 相似文献
13.
Water Resources - The article considers an estimate of the effect of positive feedback in the mechanism of level oscillations in the Caspian Sea on the long-term level regime. The study was based... 相似文献
14.
It is shown that the awareness of the regularities and causes of variations in the Caspian Sea level from the moment of its origin as an isolated lake basin in the Late Miocene (7.2 mln years ago) is of great importance for paleohydrology. Out of the seven principal hydrologic stages of the Caspian Sea history, four stages are considered in this paper: two lake stages (the Late Miocene and Middle Pliocene), the intermediate stage when the Caspian and Zanklinian basins were connected, and the stage of the Manych runoff. An important fact in the Caspian Sea history is emphasized: penetration of the Akchagylian fauna forebears into the Caspian Sea Basin through the Black Sea and the nowadays nonexistent Kuban–Terek Channel (between 5.3 and 3.3 mln years ago). Three phases of penetration of the Mediterranean Zanklinian fauna into the Caspian Basin are recognized. The channel became closed during the Middle Pliocene phase of the Great Caucasian Range elevation (3.3–2.5 mln years ago). This isolation of the Caspian Basin caused the formation of the Great Akchagylian Lake. Its water washed out the New Manych Channel 2.5 mln years ago. From this moment on, the events that occurred in the Caspian Basin and in the Black and Mediterranean seas can be correlated in greater detail, link by link, within the 413-thousand-year period of water abundance. 相似文献
15.
A. A. Svitoch 《Water Resources》2008,35(2):165-170
The Late Pleistocene history of the Caspian and Black seas is considered. It is suggested that the New-Euxinian basin was to a great degree due to the penetration of the Caspian water through the Manych depression into the Black Sea during the Caspian-Early Khvalynian transgression. 相似文献
16.
The Late Quaternary history of the Caspian Sea remains controversial. One of the major disagreements in this debate concerns the stratigraphic correlation of various deposits in the Caspian Basin. In this paper we identify and date, for the first time, the Enotaevka regression, lying between the two major phases of the largest Late Quaternary Caspian Sea transgression, the Khvalynian transgressive epoch, and provide a minimum estimate of sea level decrease during this regression. The River Volga is the major source of water to the Caspian; the Lower Volga region is unique in its record of palaeogeographic events, and this provides the opportunity to build a single stratigraphic and palaeogeographic history for the Pleistocene of Central Eurasia. Here we use luminescence to establish a new chronology for the largest Late Quaternary transgressive epoch of the Caspian Sea. The existing radiocarbon chronology does not allow the resolution of the two transgressive phases of this epoch (Early and Late Khvalynian). Based on clear palaeontological and geomorphological evidence, these must be very different in age, but shells associated with both transgressions gave very scattered ages of between 8 and 50 ka. This ambiguity has led to considerable discussion concerning the existence or otherwise of a deep Enotaevka regression phase between the two Khvalynian transgressions. Recently we have again identified these deposits at Kosika, on the right valley side of the Volga River. The new luminescence chronology described here, based on quartz OSL and K-feldspar pIRIR290 ages, allows us to reconstruct the complicated history of Late Quaternary sedimentation in the southern part of the Lower Volga valley. The Kosika section reflects the following major stages: (1) the earlier Khazarian transgressive epoch; (2) a decrease in the sea level with the development of a freshwater lake/lagoon in the Volga valley; and (3) the Khvalynian transgressive-regressive epoch, including both the Early and Late Khvalynian transgressive periods, and the intercalated Enotaevka regression. Sea level during the early stage of the Khvalynian transgression reached Kosika at about 23–22 ka (approx. −1 to −2 m asl). This event is of the same age as the “grey clay” strata at the base of the Leninsk section marine unit (Kurbanov et al., 2021), also formed at the beginning of the Early Khvalynian transgression. Around 15–14 ka the Khvalynian basin moved to a regressive stage, and in the northern part of the Lower Volga the top part of the well-known ‘Chocolate Clay’ accumulated. In the southern part of the valley marine accumulation stopped at about 12–13 ka. This allows us to reconstruct a decrease in Early Khvalynian basin sea level between 15–14 ka and 13–12 ka ago, of about ∼15 m. At the Kosika section sediments derived from the Enotayevka regression are visible as a weakly developed palaeosol with evidence of surficial erosion, and these sediments are now dated to 13–12 ka. At 8.6 ± 0.5 ka, during the period of the Mangyshlak regression, aeolian deflation processes reworked sediments deposited by immediately preceding Late Khvalynian transgression. 相似文献
17.
The effect of transformation of the human habitat on the medical and ecological situation is considered in the context of anticipated changes in the hydrological situation. The results of earlier studies of environmental crises (transgression of the Caspian Sea and degression of the Aral Sea) are used to show the possibility of a considerable increase in the rates of infectious and noninfectious diseases caused by a direct or indirect effect of significant changes in the hydrological and hydrogeological conditions. Regularities in the dynamics of this process have been established, which allows us to discuss possible changes in public health under new hydroclimatic conditions, in particular, under global climate changes. It is shown that the scientific principles and methods for prediction of the consequences of changes in the regime, quantity, and quality of continental waters should be improved in order to allow the assessment of their effect on public health and the development of timely preventive measures. 相似文献
18.
Space and time variations in the isotopic composition of precipitation on the IAEA/WMO network in Western Europe over 1961–1991 are analyzed. The authors came to the conclusion that climate becomes warmer and the western water transfer intensifies since the 1970s. Correlation between the observed climate changes and variations in the Caspian Sea level is detected. The effect of warming on changes in the normal annual air temperatures and the amount of precipitation in various latitudinal zones of Western Europe is assessed. The supposed periodicity of climate conditions enables their prediction. 相似文献
19.
The legal regime of the Caspian Sea has been determined under Treaties 1921 and 1940 by and between Iran and former Soviet Union. In fact, we are neither to explain it nor to determine. As understood from the provisions therein, the exploitation and use of the Caspian Sea by both countries are based on the Condominium. However, there is a 10-nautical mile strip as exclusive fishing areas which have been allocated to the states under the 1940 treaty. It means that Soviet Union and Iran may benefit the marine livings resources out of that strip on an equal manner. This right also includes the seabed and underlying bed. So, the legal regime of this sea may be based on a 10-nautical mile exclusive region for all five states and the remaining part as common and joint area under an agreement until an explaining and supervising organization is established to exploit and supervise over living and non-livings resources. 相似文献
20.
Water Resources - Water balance components for the territory of the Volga basin and Caspian Sea water area have been analyzed using the results of climatic simulation under CMIP6 Project for... 相似文献