Propagation of the Azov Sea waters in the Black sea under impact of variable winds, geostrophic currents and exchange in the Kerch Strait

Kubryakov, A. A.; Aleskerova, A. A.; Goryachkin, Yu. N.; Stanichny, S. V.; Latushkin, Alexandr A.; Fedirko, A. V.

doi:10.1016/j.pocean.2019.05.011

Cited by 13 publications

(8 citation statements)

References 53 publications

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“…During this period, the cell concentration is usually N = 2-6 × 10 6 cells per liter (Mikaelyan et al, 2011(Mikaelyan et al, , 2015, which is 2-4 times higher than in weaker winter blooms (N = 0.5-2 × 10 6 cells per liter; Kubryakova et al, 2021). The coccolithophore blooms usually occupy the upper mixed layer, which is 2-3 times larger in winter than in summer, which suggests that the total cell amount in the water column is similar in the winter and summer period (Kubryakov et al, 2019b). In Oc-tober 2005, we observed very high surface values of R rs , reaching 0.018 sr −1 , which correspond to the estimated N , reaching 10 × 10 6 cells per liter.…”

Section: Discussionmentioning

confidence: 98%

“…Such coccolithophore blooms may significantly impact the sea-sonal succession of marine phytoplankton. Particularly, they can trigger the following microbial loop -the transition of trophic energy to small species and subsequent changes in the entire trophic structure of the region (Brussaard, 2004;Kubryakov et al, 2019b). For a further detailed investigation of the response of the phytoplankton community to short-term physical processes, continuous data on the taxonomic composition of phytoplankton, based, for example, on the measurements of moored-flow cytometers, are required.…”

Section: Discussionmentioning

confidence: 99%

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Quasi-tropical cyclone caused anomalous autumn coccolithophore bloom in the Black Sea

2021

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Abstract. A quasi-tropical cyclone (QTC) observed over the Black Sea on 25–29 September 2005 caused an exceptionally strong anomalous autumn coccolithophore bloom that lasted for more than 1.5 months. The QTC induced intense upwelling, causing a decrease in sea surface temperature of 15 ∘C and an acceleration of the cyclonic Rim Current up to extreme values of 0.75 m s−1. The Rim Current transported nutrient-rich Danube plume waters from the northwestern shelf to the zone of the cyclone action. Baroclinic instabilities of the plume boundary caused intense submesoscale processes, accompanied by mixing of the shelf and upwelling of the waters. These processes triggered the initial growth of remote sensing reflectance (Rrs) on the offshore front of the plume, indicating the beginning of the coccolithophore bloom. Furthermore, the bloom shifted to the zone of the strongest upwelling in the western cyclonic gyre. Intense vertical entrainment of nutrients in this area caused the increase in chlorophyll a concentration (Chl), which was then followed by a strong bloom of coccolithophores. Advection by the Rim Current spread the bloom over the entire southern part of the Black Sea, more than 1000 km from its initial source. A month after the QTC action, Rrs in these areas reached a value of 0.018 sr−1, corresponding to an estimate of a coccolithophore concentration of 107 cells per liter.

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Section: Discussionmentioning

confidence: 98%

Section: Discussionmentioning

confidence: 99%

Quasi-tropical cyclone caused anomalous autumn coccolithophore bloom in the Black Sea

2021

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“…Локальные узкие фронты в основном выходят из состояния геострофического баланса, влияющего на более крупные вихри, что приводит к развитию вторичной циркуляции в верхних слоях океана с очень большими локализованными вертикальными скоростями. Это, в свою очередь, стимулирует обмен между поверхностью и глубинными слоями [5] и может увеличивать концентрацию и перенос взвеси в этих областях конвергенции [6][7][8]. Таким образом, эти фронты являются «горячими точками» для биологических процессов [9] и дрейфующих загрязнений [10], включая микропластик и морские водоросли.…”

Section: фронтальная динамика верхнего слояunclassified

Studies of Sub-Mesoscale Variability of the Ocean Upper Layer Based on Satellite Observations Data

Chapron¹,

Kudryavtsev²,

Collard³

et al. 2020

MGZh

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The approach represented in the article is applied to analysis of satellite scanner optical images of high spatial resolution for identifying and quantitative determining the characteristics of the sub-mesoscale dynamic processes in the ocean upper layer. Methods and Results. The Envisat AATSR and MERIS SAR-images are used as the satellite data, which permit to determine the ocean surface temperature and surface brightness in the visible range, respectively. Variations in the sea surface glitter contrasts are associated with modulations of the sea surface roughness (rms slope of short waves) on the currents. It is shown that the surface roughness contrasts correlate with the spatial inhomogeneities of the ocean surface temperature, tracing submesoscale processes in the ocean (spiral eddies, filaments, local shears of currents). The described model of formation of surface manifestations is based on interaction between the Ekman current and the main flow vorticity. Conclusions. Possibility of detecting and quantitative assessing the intense current gradients in the vicinity of sub-mesoscale fronts is shown. These gradients are manifested in the optical satellite images through the ocean surface roughness modulations. The proposed approach makes it possible to study and to assess quantitatively the dynamic processes taking place in the vicinity of the submesoscale fronts. These processes, in their turn, affect the exchange of momentum, heat and gases between the ocean and the atmosphere. The prospects of applying the sub-mesoscale variability defined from the satellite measurements, to development of the models and the systems for the ocean global observations and monitoring are discussed.

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“…int/en/forecasts/datasets/reanalysis-datasets/era-interim; last access: 20 November 2019)atmospheric forcing, which includes 3 h fields of near-surface wind velocity, temperature, and humidity and daily fields for incoming long-and shortwave radiation and total precipitation. Surface fluxes and wind stress are calculated using the CORE bulk formulae (Large and Yeager, 2004) using sea surface temperature provided by the model. The initial temperature and salinity fields of the Azov and Black seas are obtained from the climatological data given in Goptarev et al (1991) and Belokopytov (2018).…”

Section: Numerical Modelmentioning

confidence: 99%

Water exchange between the Sea of Azov and the Black Sea through the Kerch Strait

et al. 2020

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The Sea of Azov is a small, shallow, and freshened sea that receives a large freshwater discharge. Under certain external forcing conditions low-salinity waters from the Sea of Azov flow into the north-eastern part of the Black Sea through the narrow Kerch Strait and form a surface-advected buoyant plume. Water flow in the Kerch Strait also regularly occurs in the opposite direction, which results in the spreading of a bottom-advected plume of saline and dense waters from the Black Sea into the Sea of Azov. In this study we focus on the physical mechanisms that govern water exchange through the Kerch Strait and analyse the dependence of its direction and intensity on external forcing conditions. Analysis of satellite imagery, wind data, and numerical modelling shows that water exchange in the Kerch Strait is governed by a wind-induced barotropic pressure gradient. Water flow through the shallow and narrow Kerch Strait is a one-way process for the majority of the time. Outflow from the Sea of Azov to the Black Sea is induced by moderate and strong north-easterly winds, while flow into the Sea of Azov from the Black Sea occurs during wind relaxation periods. The direction and intensity of water exchange have wind-governed synoptic and seasonal variability, and they do not depend on the rate of river discharge to the Sea of Azov on an intraannual timescale. The analysed data reveal dependencies between wind forcing conditions and spatial characteristics of the buoyant plume formed by the outflow from the Sea of Azov.Published by Copernicus Publications on behalf of the European Geosciences Union.

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Propagation of the Azov Sea waters in the Black sea under impact of variable winds, geostrophic currents and exchange in the Kerch Strait

Cited by 13 publications

References 53 publications

Quasi-tropical cyclone caused anomalous autumn coccolithophore bloom in the Black Sea

Quasi-tropical cyclone caused anomalous autumn coccolithophore bloom in the Black Sea

Studies of Sub-Mesoscale Variability of the Ocean Upper Layer Based on Satellite Observations Data

Water exchange between the Sea of Azov and the Black Sea through the Kerch Strait

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