Potential for Composite Analysis in the Black Sea

Potential for Composite Analysis in the

Black Sea

Arthur Capet1_{, Mason E.}2_{, Troupin C.}2_,

Vandenbulcke L.1_{, Ananda Pascual}2 _{Gr ´egoire M.}1

1

MAST, University of Li `ege, Li `ege,Belgium

Vertical structure

Temperature − [°C] Salinity − [p.s.u] Brunt−Väisälä Freq. − [/s] Pot. density anom. − [kg/m3] Oxygen − [uM]

−200 −150 −100 −50 0 7 8 9 10 18 19 20 21 0.006 0.009 0.012 0.015 0.01813.5 14.0 14.5 15.0 15.5 16.016.50 100 200 300 Depth

Diagnostics of oxygen vertical structure

I Oxygen penetration depth

I σθat oxygen penetration depth

Vertical structure

Temperature − [°C] Salinity − [p.s.u] Brunt−Väisälä Freq. − [/s] Pot. density anom. − [kg/m3] Oxygen − [uM]

Permanent Halocline −200 −150 −100 −50 0 7 8 9 10 18 19 20 21 0.006 0.009 0.012 0.015 0.01813.5 14.0 14.5 15.0 15.5 16.016.50 100 200 300 Depth

Diagnostics of oxygen vertical structure

I Oxygen penetration depth

I σθat oxygen penetration depth

Vertical structure

Temperature − [°C] Salinity − [p.s.u] Brunt−Väisälä Freq. − [/s] Pot. density anom. − [kg/m3] Oxygen − [uM]

CIL Permanent Halocline Seasonal Thermocline −200 −150 −100 −50 0 7 8 9 10 18 19 20 21 0.006 0.009 0.012 0.015 0.01813.5 14.0 14.5 15.0 15.5 16.016.50 100 200 300 Depth

Diagnostics of oxygen vertical structure

I Oxygen penetration depth

I σθat oxygen penetration depth

Vertical structure

Temperature − [°C] Salinity − [p.s.u] Brunt−Väisälä Freq. − [/s] Pot. density anom. − [kg/m3] Oxygen − [uM]

CIL Permanent Halocline Seasonal Thermocline Oxygen penetration depth 20 uM −200 −150 −100 −50 0 7 8 9 10 18 19 20 21 0.006 0.009 0.012 0.015 0.01813.5 14.0 14.5 15.0 15.5 16.016.50 100 200 300 Depth

Diagnostics of oxygen vertical structure

I Oxygen penetration depth

I σθat oxygen penetration depth

Vertical structure

Temperature − [°C] Salinity − [p.s.u] Brunt−Väisälä Freq. − [/s] Pot. density anom. − [kg/m3] Oxygen − [uM]

Permanent Halocline Seasonal Thermocline Oxygen penetration depth 20 uM −200 −150 −100 −50 0 7 8 9 10 18 19 20 21 0.006 0.009 0.012 0.015 0.01813.514.014.515.015.516.016.50 100 200 300 Depth

Diagnostics of oxygen vertical structure

I Oxygen penetration depth

I σθat oxygen penetration depth

Vertical structure

Diagnostics of oxygen vertical structure

I Oxygen penetration depth

I σθat oxygen penetration depth

Profiles Data

I World Ocean database, R/V KNORR 2003, R/V Endeavour

2005

Profiles Data

I World Ocean database, R/V KNORR 2003, R/V Endeavour

2005

Detrending

DataInterpolationVariationalAnalysis + detrending algorithm

Deoxygenation Trends :

1955 → 2015

Oxygen penetration depth 140m → 90 m

Oxygen penetration σθ 16.05 kg m−3 → 15.4 kg m−3

Oxygen inventory -44%

Deoxygenation Trends :

1955 → 2015

Oxygen penetration depth 140m → 90 m

Oxygen penetration σθ 16.05 kg m−3 → 15.4 kg m−3

Oxygen inventory -44%

Deoxygenation Trends :

1955 → 2015

Oxygen penetration depth 140m → 90 m

Oxygen penetration σθ 16.05 kg m−3 → 15.4 kg m−3

Oxygen inventory -44%

Spatial variability

Spatial variability

Oxygen penetration depth

I Dome shape due to

cyclonic circulation

Spatial variability

Oxygen penetration σθ _{I Bosphorus plume oxygen} injections

I Advection of Bosphorus

injections

I Diapycnal mixing in the

periphery

Ostrovskii and Zatsepin, 2016, DSRI

Spatial variability

Oxygen penetration σθ _{I Bosphorus plume oxygen} injections

I Advection of Bosphorus

injections

I Diapycnal mixing in the

periphery

Ostrovskii and Zatsepin, 2016, DSRI

Spatial variability

Oxygen penetration σθ

I Bosphorus plume oxygen

injections

I Advection of Bosphorus

injections

I Diapycnal mixing in the

periphery

Ostrovskii and Zatsepin, 2016, DSRI

Diapycnal mixing in the open ?

Composite Analysis

Matches [2005-2015]

Matches [2005-2015]

Blue: All ARGORed: ARGO with Oxygen

Coastal resolution ?

Lack of Eddies identification near the coast.

Potential improvement by regridding AVISO along-track data (DIVA)

Coastal resolution ?

Lack of Eddies identification near the coast.

Potential improvement by regridding AVISO along-track data (DIVA)

Coastal resolution ?

Lack of Eddies identification near the coast.

Potential improvement by regridding AVISO along-track data (DIVA)

Coastal resolution ?

Lack of Eddies identification near the coast.

Potential improvement by regridding AVISO along-track data (DIVA)

Slight improvement of Tide Gauge (PSMSL) validation (AVISO2010;AVISO2014;DIVA)

Conclusions

I Quantifying ventilation processes needed to forecast the

future trend of BS oxycline depth.

I Potential for composite analysis in the Black Sea (Altimetry

+ Argo)

I Challenge: Better resolution of coastal eddies (DIVA, Escudier et al. 2014, ...)

Thanks for your attention

and questions

More info on :

Decline of the Black Sea oxygen inventory: Capet et al, 2016, Biogeosciences

DIVA detrending algorithm:

Capet et al, 2014, Ocean Dynamics Ventilation along BS coasts :

Ostroovski and Zatsepin, 2016, DSRI Python eddy tracker :

CIL ventilation

Oxygen Content − [mol/m²]

10 20 30 40 −400 −300 −200 −100 0

CIL Cold Content − [106 J/m²]

Oxygen Content − [mol/m²]

Period 1955 − 1975 −400 −300 −200 −100 0

CIL Cold Content − [106 J/m²]

CIL ventilation

Oxygen Content − [mol/m²]

10 20 30 40 −400 −300 −200 −100 0

CIL Cold Content − [106 J/m²]

Oxygen Content − [mol/m²]

Period 1955 − 1975 1976 − 1985 −400 −300 −200 −100 0

CIL Cold Content − [106 J/m²]

CIL ventilation

Oxygen Content − [mol/m²]

10 20 30 40 −400 −300 −200 −100 0

CIL Cold Content − [106 J/m²]

Oxygen Content − [mol/m²]

Period 1955 − 1975 1976 − 1985 1986 − 1998 −400 −300 −200 −100 0

CIL Cold Content − [106 J/m²]

CIL ventilation

Oxygen Content − [mol/m²]

10 20 30 40 −400 −300 −200 −100 0

CIL Cold Content − [106 J/m²]

Oxygen Content − [mol/m²]

Period 1955 − 1975 1976 − 1985 1986 − 1998 1999 − 2016 −400 −300 −200 −100 0

CIL Cold Content − [106 J/m²]