scholarly journals Сhanges of the Structure Indicators and the Salinity Field Average Value in the Sea of Azov

2021 ◽  
Vol 28 (3) ◽  
Author(s):  
E. O. Spiridonova ◽  
B. N. Panov ◽  
◽  
Keyword(s):  
Correlation Function ◽  
Spatial Correlation ◽  
Water Exchange ◽  
Bottom Layer ◽  
Sea Of Azov ◽  
Concentration Region ◽  
Spatial Correlation Function ◽  
Salinity Field ◽  
Azov Sea ◽  
Kerch Strait

Purpose. The work is aimed at continuing the started in the previous papers investigations of structure of the Azov Sea salinity field based on the oceanographic survey data collected since 2000. Interest in studying this parameter is conditioned by its anomalous increase after 2006. Methods and Results. The data of 49 seasonal oceanographic surveys carried out in the Sea of Azov by the Azov-Black Sea Branch of "VNIRO" ("AzNIIRKH") from 2001 to 2016 permitted to calculate the following: the radii in the concentration region of the field spatial correlation function in the meridional and zonal directions for the surface and bottom layers (the characteristic of the field homogeneity); the ratio between these radii; the sea-average values of salinity field for the surface and bottom layers. The time graphical and the paired correlation analyses of the calculated indicators’ series were done. The average values of the meridional and zonal radii of the concentration region of the spatial correlation function (42.5 and 47.1 km) testify presence of two relatively isolated zones in the sea related to the water circulation. These zones are formed under the conditions of the eastern winds dominating in the region. The average values of the above-mentioned radii the near-bottom sea layer were approximately equal, whereas in the surface layer, the average zonal radii exceeded the meridional ones. In spring and summer, the meridional radius in the bottom layer surpassed the zonal one. Long-term variability shows that in the surface layer, the meridional radius values tend to increase, and in the bottom layer, the zonal radius ones – to decrease. These trends demonstrate a change in the nature of water exchange in the sea, namely from predominance of the zonal transport to that of the meridional one. Conclusions. Since 2006, the changes in the structure of the Azov Sea water salinity field (trends towards decrease of the zonal radii and increase of the meridional ones in the concentration region of the field spatial correlation function) resulted from decrease in the river water inflow and increase of water exchange with the Kerch Strait, and were accompanied by growth of average salinity. Water exchange with the Kerch Strait in the bottom layer was the most active in spring and summer. The anticipatory shift of the field structural characteristics by 1 and 2 years relative to its average values makes it possible to forecast them with a two-year advance time.

Сhanges of the Structure Indicators and the Salinity Field Average Value in the Sea of Azov

2021 ◽  
Vol 37 (3) ◽  
Author(s):  
E. O. Spiridonova ◽  
B. N. Panov ◽  
◽  
◽  
Keyword(s):  
Correlation Function ◽  
Spatial Correlation ◽  
Water Exchange ◽  
Bottom Layer ◽  
Sea Of Azov ◽  
Concentration Region ◽  
Spatial Correlation Function ◽  
Salinity Field ◽  
Azov Sea ◽  
Kerch Strait

Purpose. The work is aimed at continuing the started in the previous papers investigations of structure of the Azov Sea salinity field based on the oceanographic survey data collected since 2000. Interest in studying this parameter is conditioned by its anomalous increase after 2006. Methods and Results. The data of 49 seasonal oceanographic surveys carried out in the Sea of Azov by the Azov-Black Sea Branch of "VNIRO" ("AzNIIRKH") from 2001 to 2016 permitted to calculate the following: the radii in the concentration region of the field spatial correlation function in the meridional and zonal directions for the surface and bottom layers (the characteristic of the field homogeneity); the ratio between these radii; the sea-average values of salinity field for the surface and bottom layers. The time graphical and the paired correlation analyses of the calculated indicators’ series were done. The average values of the meridional and zonal radii of the concentration region of the spatial correlation function (42.5 and 47.1 km) testify presence of two relatively isolated zones in the sea related to the water circulation. These zones are formed under the conditions of the eastern winds dominating in the region. The average values of the above-mentioned radii in the near-bottom sea layer were approximately equal, whereas in the surface layer, the average zonal radii exceeded the meridional ones. In spring and summer, the meridional radius in the bottom layer surpassed the zonal one. Long-term variability shows that in the surface layer, the meridional radius values tend to increase, and in the bottom layer, the zonal radius ones – to decrease. These trends demonstrate a change in the nature of water exchange in the sea, namely from predominance of the zonal transport to that of the meridional one. Conclusions. Since 2006, the changes in the structure of the Azov Sea water salinity field (trends towards decrease of the zonal radii and increase of the meridional ones in the concentration region of the field spatial correlation function) resulted from decrease in the river water inflow and increase of water exchange with the Kerch Strait, and were accompanied by growth of average salinity. Water exchange with the Kerch Strait in the bottom layer was the most active in spring and summer. The anticipatory shift of the field structural characteristics by 1 and 2 years relative to its average values makes it possible to forecast them with a two-year advance time.

Study of water exchange in Kerch strait using NEMO model of Black Sea

2021 ◽  
Author(s):  
Roman Sedakov ◽  
Barnier Bernard ◽  
Jean-Marc Molines ◽  
Anastasiya Mershavka
Keyword(s):  
Water Flow ◽  
Black Sea ◽  
Water Exchange ◽  
Discharge Rate ◽  
The Black Sea ◽  
External Forcing ◽  
Sea Of Azov ◽  
The Sea Of Azov ◽  
The North ◽  
Kerch Strait

<p>The Sea of Azov is a small, shallow, and freshened sea that receives a large freshwater discharge. Under certain external forcing conditions brackish water 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 an advected plume of saline and dense water from the Black Sea into the Sea of Azov. Using a regional Black Sea Azov Sea model based on NEMO we study physical mechanisms that govern water exchange through the Kerch Strait and analyze the dependence of its direction and intensity on external forcing conditions. We show 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 northerly winds, while flow into the Sea of Azov from the Black Sea is induced by southerly winds. The direction and intensity of water exchange have wind-governed synoptic and seasonal variability, and they do not depend on the variability of river discharge rate to the Sea of Azov on an intraannual timescale.</p>

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

Ocean Science ◽  
2020 ◽  
Vol 16 (1) ◽  
pp. 15-30 ◽  
Author(s):  
Ivan Zavialov ◽  
Alexander Osadchiev ◽  
Roman Sedakov ◽  
Bernard Barnier ◽  
Jean-Marc Molines ◽  
...  
Keyword(s):  
Water Flow ◽  
Black Sea ◽  
Water Exchange ◽  
The Black Sea ◽  
External Forcing ◽  
Sea Of Azov ◽  
Buoyant Plume ◽  
The Sea Of Azov ◽  
The North ◽  
Kerch Strait

Abstract. 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 intra-annual 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.

Optical and X-Ray Clusters as Tracers of the Supercluster-Void Network. II. The Spatial Correlation Function

2002 ◽  
Vol 123 (1) ◽  
pp. 37-50 ◽  
Author(s):  
E. Tago ◽  
E. Saar ◽  
J. Einasto ◽  
M. Einasto ◽  
V. Müller ◽  
...  
Keyword(s):  
Correlation Function ◽  
Spatial Correlation ◽  
Spatial Correlation Function ◽  
X Ray
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