The seasonal variations of the The seasonal variations of the climatic circulation of the Black climatic circulation of the Black Sea waters along the axis of Sea waters along the axis of

divergence zone. divergence zone.

O.R.AndrianovaO.R.Andrianova,, R.R.Belevich, M.I.Skipa R.R.Belevich, M.I.Skipa

Hydroacoustic Branch of MHI NASUHydroacoustic Branch of MHI NASU Odessa, UkraineOdessa, Ukraine

The aim of this work is :The aim of this work is :detecting of features of the seasonal detecting of features of the seasonal water circulation in the surface and water circulation in the surface and intermediate layers of the Black Sea intermediate layers of the Black Sea open waters, which is based on an open waters, which is based on an analysis of the dynamic heights analysis of the dynamic heights distribution along the axis of the main distribution along the axis of the main Black Sea divergence zone.Black Sea divergence zone.

The map of the temperature and salinity data by The map of the temperature and salinity data by squares in the Black Sea squares in the Black Sea

Annual climatic Annual climatic maps of the maps of the dynamic dynamic topography layers topography layers of the Black Sea of the Black Sea (dotted line is the (dotted line is the position of the axis position of the axis of the divergence of the divergence zone).zone).

(a) 0-50 m (a) 0-50 m (b) 0-500 m (b) 0-500 m

The distribution of the The distribution of the dynamic heights along dynamic heights along an divergence zone an divergence zone axis of the Black Sea by axis of the Black Sea by monthsmonths for layerfor layer 0-50 0-50mm

1, 31, 3 –– centers of western centers of western and eastern cyclonic gyresand eastern cyclonic gyres, , 2-2-ridgeridge, , ellipses schematically show ellipses schematically show the positions of the cyclonic the positions of the cyclonic gyres,gyres,II--XII - monthsXII - months..

Ellipses schematically show the positions of the cyclonic gyres, vertical line - ridge, dotted lines – centers of the cyclonic gyres.

1- Coastal back and forth current2- Main Black Sea’s current3 - Counter current4 - Western branch of the Western cyclonic gyre5 - Eastern branch of the Western cyclonic gyre6 - Western branch of the Eastern cyclonic gyre7- Eastern branch of the Eastern cyclonic gyre  

The distribution of the dynamic topography along the The distribution of the dynamic topography along the axis of the divergence zone for the horizons by the axis of the divergence zone for the horizons by the seasons seasons

Annual climatic map of dynamic topography of layer 0-500 m of the Black Annual climatic map of dynamic topography of layer 0-500 m of the Black Sea (dotted line shows the position of the axis of the divergence zone).Sea (dotted line shows the position of the axis of the divergence zone).

a) - wintera) - winter,, spring; b) - summer spring; b) - summer, , autumn.autumn.

WinterWinter (1,3,5); (1,3,5); SpringSpring (2,4,6); (2,4,6); Summer Summer (7,9,11);(7,9,11); Autumn Autumn ((8,10,12)8,10,12)Western Zn (1,2,7,8); Western Zn (1,2,7,8); RRidge (3,4,9,10); Eastern Zn (5,6,11,12)idge (3,4,9,10); Eastern Zn (5,6,11,12)

The scheme of the position of the centers of western and The scheme of the position of the centers of western and eastern cyclonic gyres and the ridge by the depth, by eastern cyclonic gyres and the ridge by the depth, by longitude and by the seasonslongitude and by the seasons

Climatic characteristics of the cyclonic circulations in Climatic characteristics of the cyclonic circulations in the Black Sea along the axis of the divergence zonethe Black Sea along the axis of the divergence zone

SeasonSeason

West cyclonic gyre zoneWest cyclonic gyre zone RRidge idge East cyclonic gyre zoneEast cyclonic gyre zone

LLengthength WidthWidth Center Center locationlocation

Center Center locationlocation LLengthength WidthWidth Center Center

locationlocation

WinterWinter 31-3431-34 33 3232 3434 34-3834-38 44 3636SpringSpring 29-3529-35 66 3333 3535 35-3835-38 33 3636SummSumm

erer 29-3529-35 66 3232 3535 35-4135-41 66 3636AutumAutum

nn 31-3531-35 44 3333 3535 35-3835-38 33 3636

(Values shown in degrees of East longitude)(Values shown in degrees of East longitude)

ConclusionsConclusions For the first time the divergence zone of the Black Sea was identified and For the first time the divergence zone of the Black Sea was identified and

described. described. The axis of divergence zone was determined. This axis is situated in the The axis of divergence zone was determined. This axis is situated in the

middle part of the Black Sea and stretches from south coast of Bulgaria till middle part of the Black Sea and stretches from south coast of Bulgaria till south coast of Caucasus.south coast of Caucasus.

The specific features of the structure, spatial distribution and seasonal The specific features of the structure, spatial distribution and seasonal variability of flows and gyres that placed along the divergence’s zone in the variability of flows and gyres that placed along the divergence’s zone in the surface and intermediate layers were found out.surface and intermediate layers were found out.

Seasonal variability of positions and intensity were estimated for Main Black Seasonal variability of positions and intensity were estimated for Main Black Sea’s Current, cyclonic gyres and ridge. Velocities of the currents were Sea’s Current, cyclonic gyres and ridge. Velocities of the currents were calculated.calculated.

The The impactimpact of spring floods of spring floods ofof the rivers the rivers inin the north-western the north-western region of region of Black Black Sea Sea to the to the water circulation in the surface layerwater circulation in the surface layers ins in the open sea area was the open sea area was describeddescribed..

Three separate types of the circulation in the open waters of the Black Sea Three separate types of the circulation in the open waters of the Black Sea were detected in an annual cycle:were detected in an annual cycle:

- In winter equivalent western and eastern cyclonic gyres occur.- In winter equivalent western and eastern cyclonic gyres occur.

- In spring western cyclonic gyre dominates.- In spring western cyclonic gyre dominates.

- In summer and autumn the eastern cyclonic gyre dominates.- In summer and autumn the eastern cyclonic gyre dominates.

Obtained results certainly should be very important for data analysis and Obtained results certainly should be very important for data analysis and development of prognostic models of ecological situations in the Black Sea. development of prognostic models of ecological situations in the Black Sea.

Thanks for your Thanks for your attention!attention!

The average (normal component) current velocity (cm / s) The average (normal component) current velocity (cm / s) according to the season in streams of water allocated along the according to the season in streams of water allocated along the

divergence of horizons (m)divergence of horizons (m)

    WINTER  

м

CBFC

MBSC

CCWBWZn

EBWZn WBEZn EBEZn CC MBSC CBFC

0 -6 -55 -3 -25 1 22 -14 -14 5 23 3 8 51 22

10 -4 -52 -2 -10 1 21 -14 -14 10 22 3 8 46 19

30 -1 -51 -1 -9 0 22 -14 -13 10 17 3 6 46 19

50 0 -50 1 -10 1 21 -11 -13 9 16 1 6 44 18

75 0 -45 2 -10 2 19 -8 -12 6 14 1 5 38 16

100 0 37 3 -3   16 -8 -10 5 12 -1 3 32 13

150 0 25 3 -7 4 11 -4 -8 3 10 -3 3 19 4

200 0 17 1 -6 4 8 -3 -6 1 8 -4 4 12 0

300 0 6 0 -3 2 4 -2 -3 1 1 0 4 6 0

    SPRING  

м

CBFC

MBSC+WBWZn EBWZnWBEZn

EBEZn CC MBSC CBFC

0 -12 -58 -10 -4 -1 16 10 1 -1 17 2 27 38 13

10 -10 -56 -10 -4 -2 16 6 3 -2 17 2 27 35 8

30 -10 -52 -9 -4 -1 15 6 -3 0 15 1 27 33 4

50 0 -56 -7 -5 -2 14 5 -2 1 14 1 26 32 5

75 0 -50 -4 -1 -3 12 4 -3 1 12 1 24 29 5

100 -1 -38 -2 1 -4 10 3 -3 1 10 -1 21 23 4

150 4 -26 -2 3 -4 8 1 -2 2 6 -1 12 14 2

200 0 -14 -1 2 -3 6 -1 -1 1 4 -2 9 10 0

300 0 -6 1 -1 3 3 -1 0 -1 3 -1 4 3 0

                             

E 28 29 30 31 32 33 34 35 36 37 38 39 40 41 41,6

    SUMMER  

м

CBFC

MBSC+WBWZn EBWZnWBEZn

EBEZn + MBSC CBFC

0 -12 -18 -16 -11 11 12 4 -20 4 5 22 36 25 -7

10 -9 -17 -16 -10 11 11 3 -16 2 4 17 28 23 -4

30 -6 -17 -15 -10 13 14 4 -12 5 2 21 28 19 -2

50 -3 -17 -12 -9 13 13 5 -18 6 1 25 25 17 -4

75 0 -14 -11 -7 12 11 4 -16 4 3 9 28 12 4

100 0 -9 -9 6 12 8 3 -14 3 3 12 17 14 -4

150 0 -9 0 -4 10 6 -4 -7 3 4 5 10 10 -2

200 0 -5 0 -3 7 2 1 -9 4 3 -1 9 7 0

300 0 -3 1 -2 3 2 -1 -3 2 1 -3 8 2 1

                             

    AUTUMN  

м

CBFC

MBSC

CC WBWZn EBWZnWBEZn

EBEZn CC MBSC CBFC

0 -5 -39 2 -11 -13 12 10 -15 3 23 -1 25 39 -1

10 -4 -39 3 -11 -15 11 12 -16 3 22 -1 24 26 10

30 -2 -39 3 -10 -9 12 12 -16 6 17 -1 23 23 7

50 0 -36 4 -8 -9 10 13 -16 6 16 -1 21 21 5

75 0 -31 5 -7 -4 9 12 -14 6 14 -3 21 17 3

100 0 -27 6 -6 -3 7 10 -12 5 12 -3 18 13 3

150 0 -19 5 -3 -1 6 6 -7 3 7 -1 10 10 -2

200 0 -15 5 -3 -1 4 4 -4 2 4 -1 6 6 -1

300 0 -2 1 0 -1 3 1 -1 3 0 0 0 6 0

                             

E 28 29 30 31 32 33 34 35 36 37 38 39 40 41 41,6

The average (normal component) current velocity (cm / s) The average (normal component) current velocity (cm / s) according to the season in streams of water allocated along the according to the season in streams of water allocated along the

divergence of horizons (m)divergence of horizons (m)

The scheme of water circulation in the Black Sea The scheme of water circulation in the Black Sea

1 – Main Black sea current (MBSC) – average position of a core; 2 – meanders of MBSC; 3 – Coastal anticyclonic eddy (CAE); 4 – cyclonic eddy (CE); 5 – Batumi anticyclonic eddy; 6 – Kaliakra CAE; 7 – Sevastopol CAE; 8 – Kerch CAE; 9 – quasistationary cyclonic gyre.