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1.
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
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.
The Caspian Sea is characterized in the geographic and ecological aspects, and the state of its ecosystem is estimated. The natural and anthropogenic processes that control the formation of the environmental conditions in the Caspian Sea and the distribution of principal commercial hydrobionts and their food items are analyzed. Data on modern tendencies in changes in the abiotic and biotic parameters of the ecosystem, their causes and mechanisms are summarized. Prospects of further changes related to the development of shelf fields of petroleum hydrocarbons are assessed. 相似文献
4.
The results of studying the hydrological regime of the Caspian Sea and its basin climate in observation period 1945–2010 are generalized. The results of analysis of the regime of precipitation, air temperature in the Caspian Sea basin and its level, as well as Volga runoff in periods of Caspian Sea level rise and drop are given. The conformity in variations of the trends in Caspian Sea level its basin climate is demonstrated, and the direction of further studies is substantiated. 相似文献
5.
Long-term variability in water temperature and salinity in August has been determined for deep-water segments of standard profiles in the Central and Southern Caspian Sea based on data of on-board observations carried out in 1956–2000. Estimates of parameters of the vertical thermohaline structure of waters were obtained for four time intervals. These estimates have been compared to the variability in the main external factors governing the formation of thermohaline regime. Appreciable long-term variations in the vertical thermohaline structure of waters, caused by a nonperiodic alternation of two main types of hydrological processes in the Caspian Sea are revealed. Qualitative characteristics of these two types are presented. 相似文献
6.
The concentrations and the elemental and biochemical composition of dissolved and particulate organic matter (OM) characteristic of southern and Arctic seas are presented. The rate of OM transformation in the production–decomposition cycle and that of the phosphate cycle are estimated from the activity of the redox enzymes of the electron-transport system and that of phosphatase. Carbohydrates and protein are shown to be the main biochemical components in the water of all the seas under study in dissolved and particulate OM, respectively. The contribution of carbohydrates to particulate OM under the conditions of intense primary production is demonstrated to be comparable to that of protein. High concentrations of lipids are shown to be characteristic of the coastal ecosystems in the middle Caspian Sea and northwestern shelf of the Black Sea because of severe pollution in these areas. It is noted that at higher trophic levels, the ecosystem of the Caspian Sea intensely assimilates allochthonous OM, and that the Black Sea ecosystem transfers considerable amounts of OM to the hydrogen sulfide zone. 相似文献
7.
Nonlinear dynamics of level variations in the Caspian Sea 总被引：2，自引：0，他引：2
Caspian Sea level variations, which have several equilibrium states, are studied by the methods of the theory of nonlinear dynamic systems. Normal monthly values of sea level according to data collected at Makhachkala gauge from 1900 to 2000 are considered. The diagnostic characteristics of dynamic chaos are used to show that sea level variations have some properties of series with chaotic behavior. A model of level variations in the Caspian Sea, comprising a system of water balance equations for the sea basin, the dynamics of river runoff, and water balance of the sea itself, is proposed. Equation of a nonlinear oscillator is derived and shown to have solutions with chaotic regimes at some combinations of parameters. 相似文献
8.
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
9.
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
10.
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
11.
Three types of brines with a characteristic composition have been distinguished in the Mezen Syneclise: with increased Na+, with relatively decreased Ca2+, and with relatively increased Ca2+. Rock salt dissolution has been shown to be substantial in the first-type brine formation. It has been noted that these brines are very dynamic and extremely young. The second-type brines have been shown to be of sedimentation origin and have a stagnant regime at relatively low temperatures; gypsum dissolution and metamorphization under stagnant conditions at increased temperatures have been shown to be substantial at the first and the following stages of formation of the third-type brines. 相似文献
12.
M. V. Isupova 《Water Resources》2008,35(6):615-634
Long-term water level variations in the Volga mouth area and the effect exerted on them by the river’s flow and the Caspian Sea’s level variations are considered. Quantitative relationships were identified between the mean annual water levels at different gages in the mouth and the sea level. A backwater component was isolated in the long-term variations in water level in the Volga mouth area. Relationships between the daily water levels in the mouth and the Caspian Sea’s level at fixed water flow in the delta apex are presented. The magnitude and the propagation distance of backwater from the sea into the delta are specified. The responses of the mouth areas of rivers emptying into the Caspian Sea to sea level variations in the past century are compared. 相似文献
13.
A. P. Demin 《Water Resources》2007,34(3):237-253
Indices characterizing the withdrawal of water resources in the basins of rivers flowing into the Caspian Sea and the use of these resources in different economic sectors in 1970–2003 are analyzed. The dynamics of disposal of wastewaters and collector-drainage waters is discussed. Tendencies in changes in the volumes of consumptive water use in the basins of individual rivers and the Caspian Sea as a whole are identified. 相似文献
14.
Water Resources - The reliability of various scenarios of vertical structure formation in Caspian Sea water was analyzed based on the distribution of transient tracers (CFC-11, CFC-12, 3H, and 3He)... 相似文献
15.
Application of the Ordered Weighted Averaging (OWA) method to the Caspian Sea conflict 总被引：1，自引：0，他引：1
Hojjat Mianabadi Majid Sheikhmohammady Erik Mostert Nick Van de Giesen 《Stochastic Environmental Research and Risk Assessment (SERRA)》2014,28(6):1359-1372
This study proposes a promising allocation mechanism of the Caspian Sea natural resources, which are presently shared among five countries. To date, these nations have been unable to reach an allocation agreement. We apply a methodology to propose the most appropriate solution under different risk attitudes of the states. This research is different from other studies regarding the Caspian Sea negotiations in that it employs risk-based fuzzy multi attribute decision making methods for simulating the risk attitudes or optimism/pessimism degrees of the decision makers. The ordered weighted averaging (OWA) approach, which considers the optimism/pessimism degree quantitatively, is used to take into account the effects of different risk attitudes of the negotiators on the final outcome. We demonstrate how one could obtain a range of alternatives under different multi attribute and risk attitudes. The induced OWA (IOWA) method is also used to determine the relative power of these states bordering the Caspian Sea by considering several attributes, including different risk attitudes of agents. Results indicate that taking into account the risk attitude (prone, neutral, averse) of the states can affect the overall ranking of the proposed solutions. The findings from this study may facilitate negotiation regarding the most preferred allocation mechanism for the Caspian Sea. 相似文献
16.
Aliphatic and aromatic hydrocarbons in coastal Caspian Sea sediments 总被引：17，自引：0，他引：17
Tolosa I de Mora S Sheikholeslami MR Villeneuve JP Bartocci J Cattini C 《Marine pollution bulletin》2004,48(1-2):44-60
This investigation represents the first extensive study of the spatial distribution and sources of aliphatic (n-alkanes and unresolved complex mixture of fossil hydrocarbons) and polycyclic aromatic hydrocarbons (PAHs) in coastal sediments from the Caspian Sea. PAH concentrations, n-alkanes and biomarker profiles all suggested that there was limited petrogenic contamination in the shallow North Caspian Sea sediments, which are coarse with a low total organic carbon content. In contrast, moderate to high petrogenic contamination was found in the South Caspian Sea, in particular in the offshore oil fields near Baku, Azerbaijan. Contaminant patterns indicated that the PAHs were mainly from fossil sources, with higher contributions of pyrolytic only near industrialized and urban areas. A high contribution of perylene, a geochemically derived PAH, to the total PAHs was found in the west and south at sites influenced by the Kura, Safid Rud, Terek, Sulak and Samur Rivers. 相似文献
17.
The results of determinations of macro- and microelement concentrations (Mn, Fe, Ba, Sr, Rb, Si, Pb, and U) in the interstitial water in four cores of bottom sediments sampled in the deep-water areas of the Southern and Middle Caspian Sea are compared with the concentrations of these elements in the free water of the Caspian Sea. The data obtained amplify the present-day concept on the geochemical and ecological states of the sea. 相似文献
18.
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
19.
Analysis and interpretation of the distribution of anthropogenic radionuclides 90Sr, 137Cs, and 239,240Pu in the Caspian Sea water are presented. These radionuclides are shown to be of environmental importance and to be useful for studying water mass dynamics. 相似文献
20.
Regime characteristics of infragravitational and wind-induced waves for the northwestern Caspian Sea are given. The role of infragravitational waves in the dynamics of the northern Caspian coastal zone is determined based on empiric regional relationships, used to improve the conventional methods, and wind wave calculations. 相似文献