共查询到20条相似文献，搜索用时 31 毫秒
1.
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
2.
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
3.
Three areas with different trends in water level variations over the period of many years have been distinguished within the Kuban Delta. It was found that the eustatic level rise of the Sea of Azov and soil subsidence on the sea edge of the delta and in the lower reaches of the Protoka Branch were responsible for the noticeable rise in water levels. A considerable water level drop caused by the river runoff regulation and erosion of the lower pool of the Krasnodarskii Waterworks was recorded in the upper part of the delta; in the rest part of the delta, water levels dropped insignificantly, which was partially due to the impact of the tectonic uplift. 相似文献
4.
Correlation is established between the long-term variations in the frequency of the atmospheric circulation forms, water balance elements, and the Sea of Azov water salinity. It is found that the river runoff into the sea and the sea freshwater balance increase and the sea salinity decreases in the periods, when northern and western forms of atmospheric processes develop; in the periods with a greater frequency of the eastern type of atmospheric macroprocesses, the situation is reverse. It is also found that the effect of atmospheric circulation on the sea salinity tends to strengthen, whereas the effect of the human-induced decrease in river runoff tends to diminish. The current desalination of the Sea of Azov down to 10.5 is shown to be mainly due to the development of western and northern forms of atmospheric circulation in the cold season of a year during the last 10–15 years. 相似文献
5.
The relationship between many-year variations in zoobentbos of the Sea of Azov and the largescale variations in atmospheric
circulation (G.Ya. Vangengeim typification) from the mid-XX to the early XXI century has been considered. It has been shown
that the western form facilitates an increase in zoobentbos biomass of the Sea of Azov and the eastern form, its growth. The
effect of the northern type of macroprocesses is controversial. The change from eastern to western form in the mid-1980s caused
a freshening in the Sea of Azov and reduced the total zoobentbos biomass, especially mollusk. The farther predominance of
the western form will facilitate the preservation of the present-day structure of benthic communities up to the end of the
first quarter of the XXI century. 相似文献
6.
Legal aspects of natural resources management in the basin of the Sea of Azov are investigated. The available legal documents and agreements are carefully analyzed. Measures to be taken both to eliminate the uncertainty of the Sea of Azov legal status and to promote cooperation in the natural conservation zone between Russia and Ukraine at the international level are suggested. The experience of Mediterranean countries succeeding in marine environment protection is analyzed. 相似文献
7.
A great body of source data on the concentrations of oil products, organochlorine pesticides, and heavy metals in the Azov Sea bottom sediments in 1996–2005 is analyzed. An integral quantitative characteristicóan index of pollution of bottom sedimentsóis proposed and used for elaborating a five-level classification of sea floor regions. The causes and regularities of variations in concentrations of toxicants are established and the sites of their entry into the ecosystem are localized. 相似文献
8.
The spatial-temporal variations in the amount and biochemical composition of organic matter and the rates of its transformations in the ecosystems of the Russian part of the Sea of Azov are analyzed. Maximum OM concentrations are typical for Taganrog Bay. A characteristic feature of the Sea of Azov is a large proportion of particulate organic matter, which in summer in Taganrog Bay exceeded 35%. It is shown that not only the concentration of organic matter changes from season to season, but also its elementary (Corg, Norg, and Porg) and biochemical composition (proteins, carbohydrates, and lipids). The major biochemical compound of dissolved organic matter is shown to be carbohydrates (13–28%), and that of particulate matter is protein (44–51%). The hydrolytic (phosphatase and protease) and oxidation-reduction enzymes of electron-transport system demonstrate a high activity in summer. The estimated short turnover times of phosphates and protein suggest the rapid and complete utilization of organic matter in the Sea of Azov. 相似文献
9.
A brief review of studies of the hydrological regime of the Sea of Azov and approaches to assessing the average salinity—a key indicator of the state of its ecosystem is given. A database of salinity measurements at 47409 oceanographic stations over hundred years (from 1913 to 2014) were used to evaluate the sea-averaged mean annual salinity. The obtained values of the average salinity were found to differ from those published before because of the different approaches used to its calculation and different volumes of data involved. The difference was most significant for Taganrog Bay because of the high variability of its hydrological regime. Anomalies of the average salinity over period 1922–2014 were constructed, and the start of one more period of salinity increase in the Sea of Azov was recognized. 相似文献
10.
The main feature of the present-day hydrological conditions governing the formation of biological production in the Sea of Azov is shown to be the appreciable freshening of seawater, which is due, first of all, to climate changes. It is established that the freshening of seawater can benefit most for the reproduction of fish resources in the Sea of Azov only if the river runoff withdrawals are reduced step by step down to 5 km3/year (14% of the norm), the annual runoff is maintained at 35–36 km3, and the spring runoff is restored to 18.5 km3. 相似文献
11.
The dynamics of concentrations of oil products spilled into the aquatic ecosystem as a result of accidents in the Kerch Strait
is discussed. Provision is made for the analysis of the results of long-term monitoring and for the revealing of differences
in concentrations and distribution of oil hydrocarbons in the Sea of Azov and in the Black Sea after emergency spills. The
available information was used to outline the course of events that led to such redistribution of spilled mazut in marine
ecosystems. 相似文献
12.
The distributions of concentrations of dissolved Sr, Ca, F, and B in the Kuban and Don mouth areas are studied. It is found that the behavior of F and B is conservative, whereas that of Sr and Ca is slightly nonconservative and is associated with the spatial heterogeneity of the structure of the zone where the river and sea waters are mixing (this heteromogeneity can arise because of dissimilar transformation of continental river runoff in different areas of the near-mouth coastal waters). It is shown that the parameters of linear relationships between the concentrations of Sr and Ca and the chlorides content of water differ in accordance with the seasonal variations in the chemical composition of the river and the Sea of Azov waters; for F and B, such regularity is not found. 相似文献
13.
Water level variations in the Kiliya Branch of the Danube Delta over the period of 40 years (1958–1997) were analyzed. These level variations were subdivided into three components related to long-term variations of the share of the branch runoff and its redistribution within a year resulting from the Danube flow regulation; subsidence of deltaic deposits; and backup caused by the rising Black Sea level. It was revealed that, during the low-flow period, this backup had propagated to the river mouth at a distance of 160 km. 相似文献
14.
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
15.
16.
The results of studies on the efficiency of identification criteria for the origin of hydrocarbons in the ecosystem of the
Sea of Azov. Their amount in the cells of major planktonic and benthic organisms of the Sea of Azov. The share of biogenic
hydrocarbons in their total amount determined by monitoring the oil pollution of the sea is also evaluated. 相似文献
17.
Sea level variations and extreme events are a major threat for coastal zones. This threat is expected to worsen with time because low-lying coastal areas are expected to become more vulnerable to flooding and land loss as sea level rises in response to climate change. Sea level variations in the coastal ocean result from a combination of different processes that act at different spatial and temporal scales. In this study, the relative importance of processes causing coastal sea level variability at different time-scales is evaluated. Contributions from the altimetry-derived sea-level (including the sea level rise due to the ocean warming and land ice loss in response to climate change), dynamical atmospheric forcing induced sea level (surges), wave-induced run-up and set-up, and astronomical tides are estimated from observational datasets and reanalyses. As these processes impact the coast differently, evaluating their importance is essential for assessment of the local coastline vulnerability. A case study is developed in the Gulf of Guinea over the 1993–2012 period. The leading contributors to sea level variability off Cotonou differ depending on the time-scales considered. The trend is largely dominated by processes included in altimetric data and to a lesser extent by swell-waves run-up. The latter dominates interannual variations. Swell-waves run-up and tides dominate subannual variability. Extreme events are due to the conjunction of high tides and large swell run-up, exhibiting a clear seasonal cycle with more events in boreal summer and a trend mostly related to the trend in altimetric-derived sea-level. 相似文献
18.
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
19.
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
20.
Water Resources - A three-dimensional ocean general circulation model (Princeton Ocean Model) along with hydraulic calculations were used to evaluate the velocity of currents from the Sea of Azov... 相似文献