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

Дианский, Н. А.; Фомин, Владимин Васильевич; Выручалкина, Татьяна Юрьевна; Владимирович, Гусев Анатолий; Diansky, N. A.; Фомин, В. В.; Vyruchalkina, T. Yu.; Гусев, А. В.

doi:10.17076/lim310

Cited by 7 publications

(3 citation statements)

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“…Вертикальное разрешение -от 2 до 30 м. Для описания горизонтальной турбулентной вязкости используется оператор четвертого порядка с параметризацией Смагоринского [15] с минимальным рекомендованным авторами безразмерным коэффициентом C = 2. Среди известных нам численных моделей Каспийского моря только две [16,17] имеют более высокое разрешение (около 1,5 км), однако используемая нами модель обладает существенно меньшим уровнем диссипации и, следовательно, бόльшим эффективным разрешением, что позволяет воспроизвести широкий спектр движений: от крупно-до мезомасштабных. Для параметризации вертикальной турбулентной вязкости применяется схема Манка -Андерсона с максимальным коэффициентом Km = 10 -3 м 2 /с.…”

Section: численный экспериментunclassified

Dynamics of the Caspian Sea Waters over the Apsheron Sill in 2003

Dyakonov¹,

Ibrayev²

2019

MGZh

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The paper is aimed at studying water exchange between the Middle and South Caspian, at assessing its intensity, spatial-temporal structure and variability. Methods and Results. The study includes the numerical model of the Caspian Sea general circulation; it is of sufficiently high resolution for reproducing mesoscale structure of the currents-2 km. Due to the model, the Caspian Sea circulation in 2003 was reconstructed and the basic characteristics of water transfer between the Middle and the South Caspian were calculated. This specific year was chosen since in all its months, the wind fields in the Middle and South Caspian water areas were in good agreement with the average climatic ones. The simulated structure of the currents over the Apsheron Sill represents the following pattern: the northward currents are most often formed over the eastern shelf slopes, and the southward onesover the western shelf slope. The latter are usually more intense and regular. From mid July to October, the easterly winds regularly occur over the Caspian Sea strengthening the northward currents, which, in their turn, transfer relatively salty and warm waters of the South Caspian to its Middle regions along the eastern coast. A fairly stable southward stream resulted from the density gradient between the cold Middle and the warm South Caspian, is located along the western shelf slope at the depths 100-150 m. On the whole, the water flow above the sill is directed from north to south. At that the southward flows are distributed rather evenly throughout the year, whereas the major part of the northward currents' flow is observed from late July to December. Conclusions. Since the South Caspian waters on all the depths are warmer and more salty than those in the Middle regions, water exchange between two basins in course of the whole year, contributes to increase both of temperature and salinity in the Middle Caspian, and to their decrease in the South Caspian, respectively. The current-originated salt flows in the region are sufficient to make salinity grow in the Middle Caspian upper layer by 0.5 psu within 100 days, at that the corresponding temperature increase does not exceed 0.01-0.03°C per day. The reverse southward currents transfer relatively fresh water to the South Caspian that lowers salinity of its upper layer by 0.2 psu per month. However, such intense intrusions are noted only in March and December. The impact of these currents on the South Caspian heat balance is more uniform throughout the year and does not exceed 0.17°C/day.

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Section: численный экспериментunclassified

Dynamics of the Caspian Sea Waters over the Apsheron Sill in 2003

Dyakonov¹,

Ibrayev²

2019

MGZh

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“…The vertical resolution is from 2 to 30 m. In order to describe the horizontal turbulent viscosity, a fourth-order operator with the Smagorinsky parameterization [15] is used with the minimum dimensionless coefficient C = 2 recommended by the authors. Among the known numerical models of the Caspian Sea, only two [16,17] have higher resolution (about 1.5 km). However, the model we use has a significantly lower level of dissipation and, therefore, a larger effective resolution, which allows us to reconstruct a wide range of movements: from largeto mesoscale ones.…”

Section: Numerical Experimentsmentioning

confidence: 99%

Dynamics of the Caspian Sea Waters over the Apsheron Sill in 2003

Dyakonov¹,

Ibrayev²

2019

PhO

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The paper is aimed at studying water exchange between the Middle and South Caspian, at assessing its intensity, spatial-temporal structure and variability. Methods and Results. The study includes the numerical model of the Caspian Sea general circulation; it is of sufficiently high resolution for reproducing mesoscale structure of the currents-2 km. Due to the model, the Caspian Sea circulation in 2003 was reconstructed and the basic characteristics of water transfer between the Middle and the South Caspian were calculated. This specific year was chosen since in all its months, the wind fields in the Middle and South Caspian water areas were in good agreement with the average climatic ones. The simulated structure of the currents over the Apsheron Sill represents the following pattern: the northward currents are most often formed over the eastern shelf slopes, and the southward ones-over the western shelf slope. The latter are usually more intense and regular. From mid-July to October, the easterly winds regularly occur over the Caspian Sea strengthening the northward currents, which, in their turn, transfer relatively salty and warm South Caspian waters to the Middle Caspian along the eastern coast. A fairly stable southward stream resulted from the density gradient between the cold Middle and the warm South Caspian, is located along the western shelf slope at the depths 100-150 m. On the whole, the water flow above the sill is directed from north to south. At that the southward flows are distributed rather evenly throughout the year, whereas the major part of the northward currents' flow is observed from late July to December. Conclusions. Since the South Caspian waters on all the depths are warmer and more salty than those in the Middle, water exchange between the two basins in course of the whole year, contributes to increase both of temperature and salinity in the Middle Caspian, and to their decrease in the South Caspian. The current-originated salt flows in the region are sufficient to make salinity grow in the Middle Caspian upper layer by 0.5 psu within 100 days, at that the corresponding temperature increase does not exceed 0.01-0.03 °C per day. The reverse southward currents transfer relatively fresh water to the South Caspian that lowers salinity of its upper layer by 0.2 psu per month. However, such intense intrusions are noted only in March and December. The impact of these currents on the South Caspian heat balance is more uniform throughout the year and does not exceed 0.17 °C/day.

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“…Currently the only source of knowledge on the Caspian Sea water circulation and exchange between its parts is numerical modelling on the basis of thermohydrodynamic models using three-dimentional temperature and salinity fields and atmospheric forcing (Trukhchev et al, 1995;Tuzhilkin et al, 1997;Ibrayev, 2001;Zil'bershtein et al, 2001;Ibrayev, Kurdyumov, 2003;Kurdyumov, Ozsoy, 2004;Popov, 2004;Ibraev, 2008;Knysh et al, 2008;Popov et al, 2009;Sarkisyan, Sündermann, 2009;Ibrayev et al, 2010;Kara et al, 2010;Farley Nicholls et al, 2012;Kitazawa, Yang, 2012;Arkhipkin et al, 2013;Popov et al, 2013;Gunduz, Ozsoy, 2014;Zyryanov, 2015;Diansky et al, 2016;Shiea et al, 2016;Zyryanov, 2016;Popov, Lobov, 2017;Diansky et al, 2018;Dyakonov, Ibrayev, 2019).…”

Section: Introductionmentioning

confidence: 99%

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

Лебедев

Kostianoy

2019

Ecol. Mont

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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.

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

Cited by 7 publications

References 1 publication

Dynamics of the Caspian Sea Waters over the Apsheron Sill in 2003

Dynamics of the Caspian Sea Waters over the Apsheron Sill in 2003

Dynamics of the Caspian Sea Waters over the Apsheron Sill in 2003

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

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