Numerical Study on Circulation and Thermohaline Structures With Effects of Icing Event in the Caspian Sea

29th International Conference on Ocean, Offshore and Arctic Engineering: Volume 3 ◽

10.1115/omae2010-20667 ◽

2010 ◽

Author(s):

Daisuke Kitazawa ◽

Jing Yang

Keyword(s):

Numerical Simulation ◽

Water Temperature ◽

Coriolis Force ◽

Caspian Sea ◽

Numerical Study ◽

Measurement Data ◽

Ocean Model ◽

Water Current ◽

The Caspian Sea ◽

Volga River

A hydrostatic and ice coupled model was developed to analyze circulation and thermohaline structures in the Caspian Sea. The northern part of the Caspian Sea freezes in the winter. Waters start icing in November and ices spread during December and January. The northern part of the Caspian Sea is covered by ices in severe winters. Ice-covered area is at its maximum during January and February, and then ices begin melting in March and disappear in April. The occurrence of ices must have significant effects on circulation and thermohaline structures as well as ecosystem in the northern Caspian Sea. In the present study, formation of ices is modeled assuming that ices do not move but spread and shrink on water surface. Under the ices, it is assumed that the exchange of momentum flux is impeded and the fluxes of heat and brine salt are given at sea-ice boundary. The ice model was coupled with a hydrostatic model based on MEC (Marine Environmental Committee) Ocean Model developed by the Japan Society of Naval Architect and Ocean Engineers. Numerical simulation was carried out for 20 years to achieve stable seasonal changes in current velocity, water temperature, and salinity. The fluxes of momentum, heat, and salt were estimated by using measurement data at 11 meteorological stations around the Caspian Sea. Inflow of Volga River was taken into account as representative of all the rivers which inflow into the Caspian Sea. Effects of icing event on circulation and thermohaline structures were discussed using the results of numerical simulation in the last year. As a result, the accuracy of predicting water temperature in the northern Caspian Sea was improved by taking the effects of icing event into account. Differences in density in the horizontal direction create several gyres with the effects of Coriolis force. The differences were caused by differences in heat capacity between coastal and open waters, differences in water temperature due to climate, and inflow of rivers in the northern Caspian Sea. The water current field in the Caspian Sea is formed by adding wind-driven current to the dominant density-driven current, which is based on horizontal differences in water temperature and salinity, and Coriolis force.

Download Full-text

THE NUMBER AND QUALITATIVE CHARACTERISTICS OF FRY FISH IN SHALLOW COASTAL WATERS OF THE VOLGA IN THE SUMMER-AUTUMN PERIOD OF 2012

VESTNIK OF ASTRAKHAN STATE TECHNICAL UNIVERSITY SERIES FISHING INDUSTRY ◽

10.24143/2073-5529-2017-3-65-73 ◽

2017 ◽

pp. 65-73

Author(s):

Edward Vladimirovich Nikitin

Keyword(s):

Fish Species ◽

Coastal Waters ◽

Caspian Sea ◽

The Caspian Sea ◽

Volga River ◽

Commercial Fish ◽

Autumn Period ◽

Fish Juveniles ◽

Qualitative Characteristics ◽

Shallow Coastal Waters

Shallow coastal waters of the Volga river is a flooded feeding area for fish juveniles of nonmigratory fish species. There takes place annual downstream migration of fluvial anadromous fish species from spawning grounds of the Volga river to the Northern Caspian Sea. The most important factors determining the number and qualitative characteristics of fry fishes are the level of the Caspian Sea (currently having a tendency to the lowering), hydrological and thermal regimes of the Volga river. Researches were carried out in definite periods of time. In the summer-autumn period of 2012 fry fishes were presented by 19 species (13 of them were commercial species), which belonged to 9 families. The article gives data on all the commercial fish species. In the first decade of July the maximum number of fry fish was registered in the western part of the Volga outfall offshore - in box 247 (19.86 mln specimens/km2), in the eastern part - in box 142 (20.4 mln specimens/km2). The most populous were roach, red-eye, silver bream and bream; size-weight characteristics were better in the areas remoted from the Volga delta. In the third decade of July the quantitative indicators of fry fish on these areas decreased, size-weight characteristics greatly increased. In the second decade of October in the western part of the seaside there were registered increased pre-wintering concentrations of fish juveniles, their qualitative indicators increased, which is evidence to favorable feeding conditions in 2012.

Download Full-text

Numerical modelling of the Caspian Sea tides

Ocean Science ◽

10.5194/os-16-209-2020 ◽

2020 ◽

Vol 16 (1) ◽

pp. 209-219

Author(s):

Igor P. Medvedev ◽

Evgueni A. Kulikov ◽

Isaac V. Fine

Keyword(s):

Caspian Sea ◽

Ocean Model ◽

Tidal Range ◽

The South ◽

Tidal Dynamics ◽

The Caspian Sea ◽

Sea Levels ◽

The North ◽

Anticlockwise Rotation ◽

Diurnal Tides

Abstract. The Caspian Sea is the largest enclosed basin on Earth and a unique subject for the analysis of tidal dynamics. Tides in the basin are produced directly by the tide-generating forces. Using the Princeton Ocean Model (POM), we examine details of the spatial and temporal features of the tidal dynamics in the Caspian Sea. We present tidal charts of the amplitudes and phase lags of the major tidal constituents, together with maps of the form factor, tidal range, and tidal current speed. Semi-diurnal tides in the Caspian Sea are determined by a Taylor amphidromic system with anticlockwise rotation. The largest M2 amplitude is 6 cm and is located in Türkmen Aylagy (called Turkmen Bay hereafter). For the diurnal constituents, the Absheron Peninsula separates two individual amphidromes with anticlockwise rotation in the north and in the south. The maximum K1 amplitudes (up to 0.7–0.8 cm) are located in (1) the south-eastern part of the basin, (2) Türkmenbaşy Gulf, (3) Mangyshlak Bay; and (4) Kizlyar Bay. As a result, the semi-diurnal tides prevail over diurnal tides in the Caspian Sea. The maximum tidal range, of up to 21 cm, has been found in Turkmen Bay. The strongest tidal currents have been located in the straits to the north and south of Ogurja Ada, where speeds reach 22 and 19 cm s−1, respectively. Numerical simulations of the tides using different mean sea levels (within a range of 5 m) indicate that spatial features of the Caspian Sea tides are strongly sensitive to changes in mean sea level.

Download Full-text

Numerical Simulation of the Caspian Sea Circulation Using the Marine and Atmospheric Research System

Water Resources ◽

10.1134/s0097807818050056 ◽

2018 ◽

Vol 45 (5) ◽

pp. 706-718 ◽

Cited By ~ 1

Author(s):

N. A. Diansky ◽

V. V. Fomin ◽

T. Yu. Vyruchalkina ◽

A. V. Gusev

Keyword(s):

Numerical Simulation ◽

Caspian Sea ◽

Research System ◽

The Caspian Sea ◽

Atmospheric Research

Download Full-text

Impact of the European Russia drought in 2010 on the Caspian Sea level

Hydrology and Earth System Sciences ◽

10.5194/hess-16-19-2012 ◽

2012 ◽

Vol 16 (1) ◽

pp. 19-27 ◽

Cited By ~ 40

Author(s):

K. Arpe ◽

S. A. G. Leroy ◽

H. Lahijani ◽

V. Khan

Keyword(s):

Sea Level ◽

Caspian Sea ◽

Analysis Data ◽

Reanalysis Data ◽

European Russia ◽

Severe Drought ◽

The Caspian Sea ◽

Volga River ◽

The Impact

Abstract. The hydrological budgets of the Volga basin (VB) and the Caspian Sea (CS) have been analysed. The components of the water balance for the CS were calculated for the period 1993 to 2010 with emphasis on summer 2010 when a severe drought developed over European Russia. A drop in precipitation over the VB in July 2010 occurs simultaneously with a decrease in evaporation for the same area, an increase of evaporation over the CS itself and a drop of the Caspian Sea level (CSL). The drop in the precipitation over the VB cannot lead to an instantaneous drop of the CSL because the precipitated water needs some months to reach the CS. The delay is estimated here to be 1 to 3 months for excessive precipitation in summer, longer for deficient precipitation and for winter cases. However, the evaporation over the CS itself is considered to be responsible for a simultaneous drop of the CSL from July to September 2010. The impact on the CSL from the precipitation deficit over the VB occurs in the months following the drought. The water deficit from July to September 2010 calculated from the anomalous precipitation minus evaporation over the VB would decrease the CSL by 22 cm, of which only 2 cm had been observed until the end of September (observed Volga River discharge anomaly). So the remaining drop of 20 cm can be expected in the months to follow if no other anomalies happen. In previous studies the precipitation over the VB has been identified as the main cause for CSL changes, but here from a 10 cm drop from beginning of July to end of September, 6 cm can be directly assigned to the enhanced evaporation over the CS itself and 2 cm due to reduced precipitation over the CS. Further periods with strong changes of the CSL are also investigated, which provide some estimates concerning the accuracy of the analysis data. The investigation was possible due to the new ECMWF interim reanalysis data which are used to provide data also for sensitive quantities like surface evaporation and precipitation. The comparison with independent data and the consistency between such data for calculating the water budget over the CS gives a high confidence in the quality of the data used. This investigation provides some scope for making forecasts of the CSL few months ahead to allow for mitigating societal impacts.

Download Full-text

ANALYSIS OF PRODUCTIVITY OF SPONGE (SPONGILLIDAE) GROWING IN WATER BODIES OF THE VOLGA RIVER DURING REGRESSION OF THE CASPIAN SEA

VESTNIK OF ASTRAKHAN STATE TECHNICAL UNIVERSITY SERIES FISHING INDUSTRY ◽

10.24143/2073-5529-2019-2-57-65 ◽

2019 ◽

pp. 57-65

Author(s):

Nikolay Aleksandrovich Franov ◽

Alexander Nickolaevich Nevalennyy ◽

Arkadii Fedorovich Sokolsky

Keyword(s):

Caspian Sea ◽

Water Bodies ◽

Raw Material ◽

Small Rivers ◽

The Caspian Sea ◽

Volga River ◽

Livestock Breeding ◽

Central Russia ◽

Microscopic Studies ◽

Effective Development

The article describes the habitat, systematics and species of freshwater sponge ( Badiaga spongia fluviatilis ) inhabiting water bodies of Russia. There have been characterized the hydrological features of water bodies - sponges’ habitats, and their ecological function has been characterized. In freshwater bodies of the central Russia there occur two most common and numerous types of sponges - lake badiaga ( Spongilla lacustris ) and river badiaga ( Ephydatia fluviatilis ) presenting a valuable raw material for the pharmaceutical and cosmetic industry. The attention is focused on the fact that sponge colonies can reach the commercial volumes only in the floodplain waters and the delta of the Volga River. Retrospective data on volumes of sponge fishery in the Astrakhan region suggest the reason for decreasing sponge productivity and volume of the sponge industry: a lack of reclamation works in small rivers in the Volga delta. There has been given a comparative analysis of the data on microscopic studies of sponge structure caught on experimental zones in the water bodies of the Astrakhan region and the information found in the scientific literature. Characteristics of soils where significant sponge plantations were found are analyzed. It has been stated that in the watercourses of the Astrakhan region there prevail species of lake sponge ( Spongilla lacustris ), whose biomass should increase tenfold taking into account the cyclicity of the regression processes of the Caspian Sea, carrying out complex ameliorative works on the waterways of the Volga and development of agriculture and livestock breeding. It has been recommended to prepare a scientific and production base for the rational and effective development of the potential of this natural resource for pharmaceutical and cosmetic purposes.

Download Full-text

Numerical modelling of the tides in the Caspian Sea

10.5194/os-2019-88 ◽

2019 ◽

Author(s):

Igor Medvedev ◽

Evgueni Kulikov ◽

Isaac Fine

Keyword(s):

Caspian Sea ◽

Numerical Experiments ◽

Ocean Model ◽

Tidal Currents ◽

Tidal Range ◽

Tidal Dynamics ◽

The Caspian Sea ◽

Southeastern Part ◽

Counterclockwise Rotation ◽

The North

Abstract. The Caspian Sea is the largest enclosed basin on the Earth and a unique object for analysis of tidal dynamics. The Caspian Sea has independent tides only, which are generated directly by tide-forming forces. Based on the Princeton Ocean Model (POM) the spatial and temporal features of tidal dynamics in the Caspian Sea were described in detail. Detailed tidal charts for amplitudes and phase lags of the major tidal harmonics, form factor, tidal range and velocity of tidal currents were plotted. Semidiurnal tides in the Caspian Sea are determined by a Taylor amphidromic system with counterclockwise rotation. The largest M2 amplitude is 6 cm and is located in the Turkmen Bay. The Absheron Peninsula splits this system into two separate amphidromies with counterclockwise rotation to the north and to the south of it. The maximum K1 amplitudes (up to 0.7–0.8 cm) are located in: (1) the southeastern part of the Caspian Sea, (2) the Türkmenbaşy Gulf, (3) the Mangyshlak Bay, and (4) the Kizlyar Bay. The semidiurnal tides prevail over diurnal tides in the Caspian Sea. The maximum tidal range has been observed in the Turkmen Bay, up to 21 cm. The highest velocity of the total tidal currents is observed in the straits to the north and south of Ogurja Ada, up to 22 cm/s and 19 cm/s, respectively. Were made numerical experiments with tidal simulation using different mean sea level MSL of the Caspian Sea (from −25 m to −30 m). Numerical experiments indicate that the spatial features of tides are strongly sensitive to the MSL changes.

Download Full-text

Numerical modeling of dynamics of Russian south waters within the framework of operational oceanography tasks

Ocean Science Discussions ◽

10.5194/osd-8-1865-2011 ◽

2011 ◽

Vol 8 (4) ◽

pp. 1865-1890

Author(s):

A. V. Grigoriev ◽

A. G. Zatsepin ◽

V. A. Kubryakov ◽

I. V. Charikov ◽

L. D. Fedotova

Keyword(s):

Black Sea ◽

Caspian Sea ◽

Horizontal Resolution ◽

Ocean Model ◽

The Black Sea ◽

The Caspian Sea ◽

Operational Oceanography ◽

Modeling Of Dynamics ◽

Climatic Information

Abstract. Modeling of the Black Sea and Caspian Sea waters dynamics was conducted within the framework of the European ECOOP project and Russian project JISWO on the basis of the Princeton Ocean Model (POM). Nowcasting and tree days forecasting of the Black Sea dynamics was carried out in a daily mode with horizontal resolution of ∼1 km along the Russian coast of the basin. The nowcasting of the Caspian Sea dynamics was carried out every ten days with horizontal resolution of ∼5 km on the basis of climatic information about water temperature and salinity and decade-averaged wind NCEP-NCAR. Examples of calculations are presented here and their comparison with space remote sensing and in situ (hydrological measurements) data is fulfilled, and the results of model validation are discussed.

Download Full-text

Interannual Variability of Water Exchange Anomalies Between the Northern, Middle and Southern Caspian Based on Satellite Altimetry Data

Ecologica Montenegrina ◽

10.37828/em.2019.25.10 ◽

2019 ◽

Vol 25 ◽

pp. 106-115 ◽

Cited By ~ 1

Author(s):

Sergey A. Lebedev ◽

Andrey G. Kostianoy

Keyword(s):

Caspian Sea ◽

Seasonal Variability ◽

Satellite Altimetry ◽

Water Exchange ◽

Western Coast ◽

Altimetry Data ◽

The Caspian Sea ◽

Volga River ◽

Geostrophic Velocities ◽

Satellite Altimetry Data

The paper presents the results of estimation of interannual and seasonal variability of water exchange between the Northern, Middle and Southern Caspian Sea based on the TOPEX/Poseidon and Jason–1/2/3 satellite altimetry data. The boundaries between the Caspian Sea sub-basins were taken along the 133 and 209 tracks of the satellites. Temporal variability of surface geostrophic velocities directed perpendicular to the tracks showed that positive values correspond to the southeast direction of the currents, negative values correspond to the northwest direction. It is clearly seen that the main water exchange associated with the Volga River runoff is concentrated along the western coast of the Caspian Sea. In this area, anomalies of geostrophic velocities exceed 20 cm/s. Total water exchange anomalies through the 133 and 209 tracks show seasonal variability with an amplitude up to ±18x105 m3/s for track 133 (a line between the Northern and Middle Caspian) and ±11x105 m3/s for track 209 (a line between the Middle and Southern Caspian). The maximum values of water exchange anomalies were observed in 1993, 1994 and 2012 through 133 track (±16-18x105 m3/s) and in 1993, 1996 and 1997 (±11x105 m3/s) through 209 track.

Download Full-text