Structure of the Black Sea Currents Based on the Results of the LADCP Observations in 2004–2014

Morozov, A. N.; Lemeshko, E.M.; Shutov, S.A.; Zima, V.V.; Deryushkin, D.V.

doi:10.22449/1573-160x-2017-1-25-40

Cited by 8 publications

(5 citation statements)

References 17 publications

(25 reference statements)

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“…In the NE Black Sea, the maximum amplitude of short-term (7-8 minutes) subsurface waves on 15 the shelf may be as high as 16 m (Bondur et al, 2018 (to be published)). In the NW Black Sea, intensive subsurface waves in the lower part of the pycnocline in the halocline were primarily observed in the continental slope area in autumn, winter and summer (Morozov et al, 2017). During these measurements in the main pycnocline in December 2012, vertical current profiles of the large internal waves with a vertical length of 50-60 m were observed.…”

Section: Discussionmentioning

confidence: 85%

The temporal variability of oxygen inventory in the NE Black Sea slope water

Ostrovskii

Зацепин

Solovyev

2018

Preprint

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Abstract. The time series of vertical profiles of hydrophysical parameters and dissolved oxygen are critical for identifying trends in water column stratification, mixing and ventilation in the Black Sea. Due to global warming, warm winters have recently become common over the Black Sea, and the temperature in the cold intermediate layer (CIL) is increasing. Regular measurements that are as frequent as every 2 h were performed using a moored profiler near the shelf break at a depth of 220 m in the northeastern Black Sea from January to early March 2016 to assess the temporal dynamics of the oxygen inventory 10 over the upper part of the continental slope on timescales from hours to months. The moored profiler was equipped with a sensor suit that included the CTD 52-MP CTD with the fast oxygen sensor SBE43F and the acoustic Doppler current meter Nortek Aquadopp 2 MHz, which allowed for direct observations of the CIL temperature, the pycnocline structure, the current velocity and the oxygen stratification, in particular, the depths of the hypoxia onset. The average oxygen inventory below a depth of 30 m was 24.9 mol m-2. Relatively high/low oxygen inventory cases were related to the thin/thick main 15 pycnocline that was associated with the inshore/offshore location of the Black Sea Rim Current. The pycnocline hindered the vertical transport of oxygenated water to the CIL. The new CIL emerged by horizontal advection above the pycnocline only at the end of the observational survey. The vertical displacements of the hypoxia onset depth ranged from 97-170 m, while the shelf edge depth in this region usually ranges from 90-100 m. Intermittently, the hypoxia boundary depth fluctuated on two time scales: ~17 h due to the inertial oscillations and approximately 5 days due to the current meanders and eddies. 20Further efforts are urgently needed for monitoring the rise of hypoxia onset depth above the shelf break in the Black Sea.

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Section: Discussionmentioning

confidence: 85%

The temporal variability of oxygen inventory in the NE Black Sea slope water

Ostrovskii

Зацепин

Solovyev

2018

Preprint

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“…As mentioned in the Section 3, the average amplitude of vertical oscillations of this isopycnal exceeds 20 m; this is a significant value, comprising about 15-20% of the total average depth of this isopycnal in the slope area of the Black Sea. Combined with a large vertical turbulent exchange coefficient in the layers with a high vertical velocity shear (such as the pycnocline) [37], the total inflow of nitrates into the photic layer can increase significantly. This aspect still needs further research.…”

Section: Discussionmentioning

confidence: 99%

Upwellings and Downwellings Caused by Mesoscale Water Dynamics in the Coastal Zone of Northeastern Black Sea

Podymov,

Ocherednik,

Silvestrova

et al. 2023

JMSE

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The paper analyzes quasiperiodic upwellings and downwellings on the shelf and upper part of continental slope of the northeastern Black Sea. It is shown that these processes are related to changes in intensity and direction of alongshore current and the following geostrophic adjustment of the density field. The source of such changes is the meandering of the Black Sea Rim Current (RC). It leads to a quasiperiodic change in direction of the alongshore current, from northwestern (cyclonic RC meander) to southeastern (anticyclonic RC meander, or eddy). These cycles, or phases, have an average duration of about 10 days. During the northwestern phase, the permanent Black Sea pycnohalocline (hereafter pycnocline) and seasonal thermocline descend, their thickness increases, and so does the thickness of the upper mixed layer (UML). During the southeastern phase, both the pycnocline and seasonal thermocline ascend and become thinner, along with the UML, which also becomes thinner. In both phases, isopycnals in the pycnocline and isotherms in the thermocline demonstrate quasi-in-phase vertical oscillations, which have a good correlation with the speed and direction of the alongshore current. These correlations allow estimation of the magnitude of upwellings and downwellings in the shelf–slope area of the northeastern Black Sea using data series of current velocity profiles.

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“…В Морском гидрофизическом институте (МГИ) в практике экспедиционных работ LADCP используется с 2004 г. Кратко результаты использования прибора в северозападной части Черного моря в 2014 г. приведены в работе [Morozov et al, 2017]. Начиная с 2016 г. институтом возобновлены регулярные крупномасштабные экспедиционные исследования в северо-восточном секторе моря.…”

Section: Introductionunclassified

Modern studies of water dynamics in the north-western part of Black sea from LADCP measurements

Morozov

Mankovskaya

2021

ICIGIS

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In this work a result of preliminary analysis of current measurements collected in fourteen large-scale expeditions of the Marine Hydrophysical Institute in 2016–2019 in the north-eastern part of the Black Sea is presented. It is shown that the use of the Lowered Acoustic Doppler Current Profiler (LADCP) significantly increases the information content of the expedition materials, opening up new opportunities in the experimental study of water dynamics. Based on the materials of the expeditions, it was found that the upper layer of shear baroclinic currents in the measurement area is limited by the isopycnic depth with a potential density of ~16.75 kg/m3 (~350 m). At this depth, the variability of the buoyancy frequency with the depth changes from a power-law to an exponential dependence. The same depth limits the penetration of seasonal variations of the average kinetic energy into the water column. The highest values of the average kinetic energy are observed in April-May and November–December, the lowest—in June–August. The ratio of the maximum energy values (summer) to its minimum values (spring, late autumn, winter) was ~3. The Rim Black Sea Current is most pronounced near the Crimean Peninsula in the spring and winter seasons. In summer and autumn, the horizontal distribution of the current velocity in depths of 30–80 m is less structured, which is caused by the seasonal intensification of mesoscale processes. At a number of stations, the current velocity profiles contain fragments with a well-defined harmonic variability of the current velocity components with depth, which can be interpreted as the manifestation of near-inertial internal waves. In most cases, the rotation of the current velocity vector with depth occurs clockwise, which determines the main direction of propagation of the inertial internal waves into the water column. The example of one of the stations shows the significant contribution of such waves to the value of shear. This fact suggests a significant influence of near-inertial internal waves on the processes of vertical turbulent exchange in the water column.

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Structure of the Black Sea Currents Based on the Results of the LADCP Observations in 2004–2014

Cited by 8 publications

References 17 publications

The temporal variability of oxygen inventory in the NE Black Sea slope water

The temporal variability of oxygen inventory in the NE Black Sea slope water

Upwellings and Downwellings Caused by Mesoscale Water Dynamics in the Coastal Zone of Northeastern Black Sea

Modern studies of water dynamics in the north-western part of Black sea from LADCP measurements

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