Acceleration of the sea surface fCO2 growth rate in the North Atlantic Subpolar Gyre (1993-2008). N. Metzl, A Corbière, G. Reverdin, A.Lenton, T. Takahashi,

Acceleration of the sea surface fCO2 growth rate in the North Atlantic Subpolar Gyre (1993-2008).

N. Metzl, A Corbière, G. Reverdin, A.Lenton, T. Takahashi, A. Olsen,

T. Johannessen, D. Pierrot, R. Wanninkhof , S. R. Ólafsdóttir, J. Olafsson and M. Ramonet

CARBOOCEAN Final meeting, Bergen, 5-10/10/09

0.0

0.5

1.0

1.5

2.0

2.5

3.0

1975 1980 1985 1990 1995 2000 2005 2010

Year

An

nu

al x

CO

2 ra

te (

pp

m/y

r)

1980-19951990-2007

Non ENSO years xCO2 from GlobalView 2009

Observing the decadal CO2 change in the ocean ?

…. Acceleration of the Atm. CO2 growth rate since 90s

Global net flux: 2 (+/-1) PgC/yrImportant improvement, but climatology is for

a virtual (e.g. non ENSO) and fixed year (here 2000)What are the temporal variations of the ocean carbon sink ?

Air-Sea CO2 flux climatology (Takahashi et al, 2009)

Moving from the climatology to trendsOne global synthesis based on observations

(CO2 fluxes)

(adapted from Le Quéré et al., in rev, 2009)

????

??????

??

??

????

Sink decreasesSink increasesDifferent regions….different trends

Moving from the climatology to trends (1)A zoom in the North Atlantic (…Go game)

(adapted from Le Quéré et al., in rev 2009)Sink decreasesSink increases

????

????

Different regions….different trends

Schuster et al. DSR SOCOVV,2009

Moving from the climatology to trends (2)Another view in the North Atlantic

(1990-2006)


Annual trend in pCO2 (μatm/yr) between 1990 and 2006

The North Atlantic carbon sink decreases almost everywhereClear signal in the subpolar gyre

Atmospheric growth rate

pCO2 trendsubpoplar gyre

Different regions….different trends


Main driver of oceanic fCO2 increase in 1990-2006:Warming in the North Atlantic Subpolar Gyre

Sea Surface Temperature trends in 1990-2006

Different regions….different processes

Another view ofNorth Atlantic

CO2 fluxes

???….???

CLIM

Schuster et al. DSR ,2009

Different models….different trends

Ocean CO2 trends in the North Atlantic

Is the ocean CO2 sink still decreases in recent years (after 2006) ?

Is warming/cooling always explains these changes ?

Schuster et al. DSR 2009

??????

Acceleration of the sea surface fCO2 growth rate in the North Atlantic Subpolar Gyre (1993-2008).

N. Metzl, A Corbière, G. Reverdin, A.Lenton, T. Takahashi, A. Olsen,

T. Johannessen, D. Pierrot, R. Wanninkhof , S. R. Ólafsdóttir, J. Olafsson and M. Ramonet

CARBOOCEAN Final meeting, Bergen, 5-10/10/09

Another view of the sea surface fCO2 changesDecadal variations in the North Atlantic Subpolar Gyre 1993-2008

Sea surface temperature, salinity, Dissolved Inorganic carbon (DIC) and Total Alkalinity (TA) observed in the Northern and Southern North Atlantic Subpolar Gyre. Winter data and trends for 1993-2003 and 2001-2008 are indicated in blue

North South



North South

Original data, T,S DIC, TA used to calculate fCO2

Trends in winter

1993-20033.6 ±0.4 µatm.yr-1

2001-2008 5.5 to 7.1 µatm.yr-1

1993-20033.6 ±0.4 µatm.yr-1

2001-2008 5.5 to 7.1 µatm.yr-1

1993-20033.6 ±0.4 µatm.yr-1

2001-2008 5.5 to 7.1 µatm.yr-1

Observed ocean fCO2 growth rates

Winter Trends in the North Atlantic Subpolar Gyre

Different periods….different trends

For recent years:comparing fCO2cal and fCO2mes

fCO2 cal: 5-7 µatm/yrfCO2mes: 5-6 µatm/yr

Wanninkhof et al.Olsen et al.

1993-20033.6 ±0.4 µatm.yr-1

2001-2008 5.5 to 7.1 µatm.yr-1

1993-20033.6 ±0.4 µatm.yr-1

2001-2008 5.5 to 7.1 µatm.yr-1

1993-20033.6 ±0.4 µatm.yr-1

2001-2008 5.5 to 7.1 µatm.yr-1

Observed ocean fCO2 growth rates

Winter Trends in the North Atlantic Subpolar Gyre

NO NAO link ?

Drivers before and after 2003?


North South



North South

Drivers ? …. Back to original data, T,S DIC, TA

+ -

=

+ -

+ + + +

++=

= =- -

-4

-2

0

2

4

6

8

SST SSS DIC TA TOTAL OBS

Ra

te o

f fC

O2

ch

an

ge

(µ

atm

/yr)

1993-2003

2001-2008

Drivers of the oceanic fCO2 trendd fCO2/ dt =(fCO2 / SST)(d SST/dt) + (fCO2 / SSS)(d SSS/ dt)

+ ( fCO2/ DIC)(d DIC / d t) + ( fCO2/ TA)(d TA / d t)

Different periods….different trends… different processes

Ratio DIC/TA: surface temporal changes and water column distribution

0

100

200

300

400

500

600

700

800

900

0.910 0.915 0.920 0.925 0.930 0.935 0.940

Ratio DIC/TA

De

pth

(m

)

1993

1995

1997

1999

2001

2003

2005

2007

2009

2011

Ye

ar

Glodap N

Glodap S

Suratlant N

Suratlant S

North/South contrast

Proposed scenario:rapid fCO2 increase

in recent years linked to vertical mixing/convection

(ARGO -Vage et al, 2008)

0.0

0.5

1.0

1.5

2.0

2.5

3.0

1975 1980 1985 1990 1995 2000 2005 2010

Year

An

nu

al x

CO

2 ra

te (

pp

m/y

r)

1980-19951990-2007

Non ENSO years

Back to the first slideAcceleration of the Atm. CO2 growth rate

xCO2 from GlobalView 2009

Observing the decadal CO2 change in the ocean ?

Ocean versus atmospheric CO2 increase

North Atlantic Subpolar Gyre

0

1

2

3

4

5

6

7

1975 1980 1985 1990 1995 2000 2005 2010

Year

An

nu

al x

CO

2 ra

te (

pp

m/y

r) 1980-19951990-2007

Non ENSO years

Ocean CO2 growth rate is faster than atmosphereThe ocean sink decreases

Evolution of oceanic and atmospheric CO

2 in the North Atlantic

Take home messages (1 fCO2 trends and processes)

+3 µatm/yr

+6 µatm/yr

WarmingConvection

Corbière et al. (2007), Metzl et al., (2009)

NO NAO

150

200

250

300

350

400

450

500

550

600

1992 1994 1996 1998 2000 2002 2004 2006 2008 2010

Year

fCO

2 (

µatm

)

pH = -0.043/decade

7.85

7.90

7.95

8.00

8.05

8.10

8.15

8.20

8.25

8.30

8.35

1992 1994 1996 1998 2000 2002 2004 2006 2008 2010

Year

pH

Evolution of oceanic CO2 in the North Atlantic

Take home message 2 (fCO2 and pH changes)

Metzl, Unpublished

Observed decadal changes of sea surface fCO2 (and fluxes)

Different regions………….. Different trends

Different inversions……… .Different trends

Different periods………….. Different trends

Different periods………….. Different processes

Next:Investigate different data-set (LDEO – SOCAT)Investigate different ocean and coupled models…………………..work in (different ) progress

SOCATUnder QC>7 Mdata

Takahashi et alDSR 2009> 3 Mdata

(r) Evolutions of surface ocean CO2

After SOCOVV meeting, 2 data-bases !!!!

Heat fluxes anomalies in winter (1999-2008)

Vage et al. 2008

Maximum winter mixed-layer in 2008

Vage et al. 2008

Global Air-Sea Fluxes: view from three CC-CCC Models

1

1.5

2

2.5

3

3.5

1975 1980 1985 1990 1995 2000 2005 2010 2015 2020 2025

Year

Air

-Sea

CO

2 F

lux

(Pg

C/y

r) IPSL

UNIBE

BCCR

Temporal variations of Air-Sea CO2 fluxesrecent past, present and future

Coupled Climate Carbon Cycle Models (source, T.Roy LSCE/IPSL)

5yr 40 yr

Global Air-Sea Fluxes: view from three CC-CCC Models

1

1.5

2

2.5

3

3.5

1975 1980 1985 1990 1995 2000 2005 2010 2015 2020 2025

Year

Air

-Sea

CO

2 F

lux

(Pg

C/y

r) IPSL

UNIBE

BCCR

CCCC Models (source, T.Roy LSCE/IPSL)

Need to validate the temporal trends

Air-Sea CO2 flux basedon atmospheric CO2 data

Nm 8/3/09

8/3/09

Global OceanAir-sea CO2 flux

?????


Annual trend in pCO2 (μatm/yr) between 1990 and 2006

The North Atlantic carbon sink decreases almost everywhereClear signal in the subpolar gyre

Atmospheric growth rate

pCO2 trendsubpoplar gyre

Documents

Acceleration of the sea surface fCO2 growth rate in the North Atlantic Subpolar Gyre (1993-2008). N. Metzl, A Corbière, G. Reverdin, A.Lenton, T. Takahashi,