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1.
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
2.
Data from cruises between 1989 and 2003 with FS Polarstern were used to construct section-wide potential temperature and salinity time series of the main water masses in the Weddell Gyre. In tandem with these CTD data, two time series between 1989 and 1995 are presented from moored instruments in the central Weddell Sea. The regional and methodological consistency of the dataset allows us to quantify variations which are not visible in less homogeneous datasets. The data reveal significant temperature and salinity variations of the Warm Deep Water and the Weddell Sea Bottom Water on a decadal time scale. The longest time series were obtained at the prime meridian. Here warming is observed in the Warm Deep Water from 1992 to 1998 followed by cooling. In the Weddell Sea proper, measurements of instruments moored in the Weddell Sea Bottom Water layer recorded a temperature increase over 6 years at a rate of 0.01 °C a–1. After the mooring period, CTD casts in 1998 point to a weakening of the trend. The warming trend in the bottom water occurs over most of the Weddell Sea, as detected in the additional CTD surveys. The variations are close to the detection level in the voluminous Weddell Sea Deep Water. The initial warming trend of the Warm Deep Water is consistent with warming trends reported in literature of subsurface waters of the Antarctic Circumpolar Current. The reversal of the trend in the Weddell Sea seems to be related to variations of the atmospheric conditions which can affect both the intrusion of Circumpolar Deep Water from the north and the circulation of the Weddell Gyre. Because the Warm Deep Water is the major source water for the formation of deep and bottom water in the Weddell Sea, it is suggested that its increase in temperature and salinity is likely to at least partly cause the variations which were observed in the bottom water.Responsible Editor: Jörg-Olaf Wolff 相似文献
3.
Mikhailov V. N. Povalishnikova E. S. Zudilina S. V. Tiguntsev L. A. 《Water Resources》2001,28(6):587-595
Studies of long-term water level variations at marine hydrometeorological stations in the eastern Sea of Azov established a rise in the sea level which accelerated in the past 40 years. Allowance for the tectonic component permitted assessing the average rate of eustatic rise in the level. Oppositely directed long-term level variations were established in the mouth area of the Don River. Water level was found to rise at the downstream gages because of the backwater effect caused by the Sea of Azov level rise and delta deposits subsidence and to drop at the upstream gages mainly because of bed erosion owing to a reduction in sediment runoff after the construction of the Tsimlyanskoe Reservoir. 相似文献
4.
Water Resources - The aims of this study was to identify the groundwater level (GWL) trend and dominant periodic component of Ardabil plain (North-west of Iran) using three variations of the... 相似文献
5.
Water Resources - The data of atmospheric reanalysis NCEP/NCAR over 1948–2017 (R-1) and NCEP/DOE over 1979–2017 (R-2) have been used to show that variations of the Caspian Sea level are... 相似文献
6.
D. C.-F. Shih G.-F. Lin 《Stochastic Environmental Research and Risk Assessment (SERRA)》2002,16(5):374-398
The water level of a seawater gauging station and 18 groundwater wells coupled with atmospheric pressure in southwestern
Taiwan are analyzed by using spectral analysis in time and frequency domain. The semidiurnal component is found to be the
most significant signal from the measurement of water level and atmospheric pressure, and the diurnal component is less distinctive
in part of water level and atmospheric pressure record. Although auto-spectral and cross-spectral density functions are significant
in atmospheric pressure and water level, the pressure variations do not significantly affect the seawater and the majority
of groundwater level in the study area with amplitude of time series observations. The astronomical tidal components are likely
the main factor causing seawater and groundwater level to fluctuate in Pingtung, Taiwan. Time lags are estimated from 20 min
to a few hours in aquifers. It concludes that the disturbance on groundwater levels from the effect of oceanic astronomical
tide is different from the varying hydrogeological characteristics of aquifer. In this study, the spectral analysis of water
level in time and frequency domains gives strong indications of sensitive variations to water level fluctuation.
This research is supported by the Institute of Nuclear Energy Research (INER), AEC, Taiwan, Republic of China, under a fund
from Executive Yuan. The authors thank Taiwan Central Weather Bureau and Taiwan Provincial Government Water Resources Department
for providing useful data. 相似文献
7.
A variable-volume, head-dependent mine water filling model 总被引：1，自引：0，他引：1
Banks D 《Ground water》2001,39(3):362-365
Current simple mine water filling models suffer from two drawbacks: (1) they often do not account for variations in mine void volume with depth; and (2) they assume that recharge to the mine is approximately constant. The Mine Water Filling Model (MIFIM) presented here rectifies these drawbacks by presenting the concept of effective area (Ea) in a lookup table and assigning deep ground water inflows a conductance whereby inflow varies in inverse proportion to mine water head, once the mine water level exceeds the level of the water inflow. The MIFIM concept may be readily programmed in a computer spreadsheet environment, with simple graphical output. The approach is particularly suited to mines in low permeability rock, with a limited number of discrete inflow features. 相似文献
8.
Water Resources - The article presents the results of hydroecological modeling of variations of phytoplankton biomass, biogenic substances, and dissolved oxygen concentration in a reach of the... 相似文献
9.
Water Resources - The short-term, seasonal, and interannual variations in the abundance and species composition of the Black Sea metazoan microzooplankton have been analyzed at the open coastal... 相似文献
10.
E. V. Shchetinina V. V. Maksimov O. V. Kraikivskaya E. A. Maksimova 《Water Resources》2013,40(6):649-656
Results of many-year (1990–2009) microbiological studies of waters in different parts of Southern Baikal subject to different anthropogenic load are presented. Long-term observation series made it possible to establish tendencies in variations of the structure and functional activity of microbiocenoses as the result of natural evolution and anthropogenic impact. The obtained microbiological data characterizes water quality and the level of technogenic disturbances near Baikal Pulp-and-Paper Mill. Water quality assessment by sanitary-bacteriological characteristics suggests that the water area near the discharge site of effluents from Baikal PPM chronically experiences bacterial pollution. No significant changes in the technogenic stress on Southern Baikal ecosystem have taken place since the 1990s. 相似文献
11.
Water Resources - The data of shipboard measurements of oxygen concentration at international monitoring stations in the Baltic Sea were used to assess the year-to-year variations of oxygen regime... 相似文献
12.
Guan-Wei Lin 《Water Resources》2019,46(5):780-788
Water Resources - Chemistry variations in the rivers are key indexes of weathering mechanisms. This paper presents a chemical variation examination of water samples acquired from 11 Taiwanese... 相似文献
13.
Koronkevich N. I. Dolgov S. V. Kashutina E. A. Mel&#;nik K. S. 《Water Resources》2019,46(1):S137-S144
Water Resources - The overland flow from different landscapes during flood season and its variations under the effect of agrotechnical activities and climate in the southern Russian Plain have been... 相似文献
14.
Water Resources - Observation data on salinity variations in the Gulf of Taganrog during storm surges are analyzed; a mathematical model of the transport of salt water masses is described in... 相似文献
15.
A streamfunction EOF method is applied to a time series of hydrographic sections in the Southern Ocean south of Australia to study water mass variations. Results show that there are large thermohaline variations north of the Subantarctic Front (SAF) at 300–1500 dbar level, indicating upwelling and downwelling of the Antarctic Intermediate Water (AAIW) along isopycnal surfaces. Based on the latest altimeter product, Absolute Dynamic Topography, a mechanism due to frontal wave propagation is proposed to explain this phenomenon, and an index for frontal waves is defined. When the frontal wave is in positive (negative) phase, the SAF flows northeastward (southeastward) with the fresh AAIW downwelling (upwelling). Such mesoscale processes greatly enhance cross-frontal exchanges of water masses. Spectral analysis shows that frontal waves in the Southern Ocean south of Australia are dominated by a period of about 130 days with a phase speed of 4 cm/s and a wavelength of 450 km. 相似文献
16.
Water Resources - The studies of seasonal variations of some hydrochemical water characteristics (salinity, oxygen content, temperature, pH, and Eh) and the state of brine shrimp population in the... 相似文献
17.
Water Resources - The processes of possible long-term variations of pH in Caucasian lakes were analyzed based on a study of lacustrine sediments from five small lakes of the Western and Central... 相似文献
18.
Water Resources - The analysis of data on the space and time variations of the concentrations and element composition of organic matter dissolved in Caspian Sea water over 2010–2015 showed... 相似文献
19.
Guanhua Zhang Ding Wenfeng Liu Huiying Yi Liang Lei Xu Zhang Ouyang 《Water Resources》2021,48(2):204-218
Water Resources - Quantifying the relative contributions of climate change and human activities to water and sediment variations is of great importance for regional resources and river basin... 相似文献
20.
Sokolova O. V. Vyruchalkina T. Yu. Solomonova I. V. Dobrovol’skii S. G. 《Water Resources》2021,48(1):7-17
Water Resources - A joint data repository on flowage lakes of the world and long-term flow variations in the rivers they regulate has been formed. The specific features of the flowage lake... 相似文献