ANTHROPOGENIC CARBON IN THE ANTHROPOGENIC CARBON IN THE ATLANTIC OCEAN: COMPARISON OF FIVE ATLANTIC OCEAN: COMPARISON OF FIVE

DATA-BASED CALCULATION METHODSDATA-BASED CALCULATION METHODS

Marcos Vázquez-Rodríguez1, Franck Touratier2, Claire Lo Monaco3, Darryn Waugh4, X.A. Padin1, Richard G. J. Bellerby5, 6, Catherine Goyet2, Nicolas Metzl3,

Aida F. Ríos1, Fiz F. Pérez1

1 Instituto de Investigaciones Marinas, CSIC, Eduardo Cabello 6, E-36208 Vigo, Spain2 BDSI, Université de Perpignan, 52 avenue Paul Alduy, Perpignan 66860, France3 LOCEAN / IPSL, Université Pierre et Marie Curie, France4 Department of Earth and Planetary Sciences, Johns Hopkins University, Baltimore, USA5 Bjerknes Centre for Climate Research, University of Bergen, Allégaten 55, 5007 Bergen, Norway6 Geophysical Institute, University of Bergen, Allégaten 70, 5007 Bergen, Norway

CARBOOCEAN 2nd Annual Meeting Gran Canarias, December 4th - 8th

Apply different methodologies to a common and recent dataset, including new data from the Arctic Ocean

Extend previous comparisons adding new methods applied at a large scale

Compare the results from five data-based methods when used to quantify the regional Anthropogenic CO2 (Cant)

Evaluate the impact of these estimates at a inventory level

AIMS OF THE STUDYAIMS OF THE STUDY

CCantant ESTIMATION ESTIMATION METHODS APPLIEDMETHODS APPLIED

CFC-shortcut [Thomas and Ittekot, 2001]

TTD [Waugh et al., 2004, 2006]

TrOCA [Touratier et al., 2004, 2006]

IPSL [Lo Monaco et al., 2005]

φCTº [Vázquez-Rodríguez et al., 2006 submitted]

Results in Lee et al. (2003) using the ∆C* method [Gruber et al., 1996] have also been included for comparison.

Data from cruises Data from cruises used used in calculations:in calculations:

- WOCE A14 (1995)WOCE A14 (1995)- WOCE I06-Sb (1996) - WOCE I06-Sb (1996) - NSeas (2002)- NSeas (2002)- CLIVAR Repeat Section - CLIVAR Repeat Section A16N (Legs 1, 2) (2003)A16N (Legs 1, 2) (2003)

-WOCE AR01 (1998)-WOCE AR01 (1998)

AAIW

CDW

AABW

NADW

LSW

MW

REGIONS OF STUDY (meridional section)

REGIONS OF STUDY (zonal section)

Mean Regional Anthropogenic CO2

0

10

20

30

40

50

60

Deep SouthAtlantic

NorthernSubtropical Gyre

SouthernSubtropical Gyre

Southern Ocean upper NordicSeas

lower NordicSeas

lower Limb ofMOC

upper DWBC lower DWBC

Can

t [um

ol k

g-1]

CFC-shortcutTTDTrOCAIPSLphi-CtºGLODAP

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

10.0

11.0

-80 -60 -40 -20 0 20 40 60 80Latitude

TrOCAIPSLTTDLee et al. (2003)phi-CtºCFC-shortcut

Inventories of Anthropogenic CO2 (Pg C)

0.0

1.0

2.0

3.0

4.0

5.0

-80 -60 -40 -20 0 20 40 60 80Latitude

TrOCAIPSLTTDCFC-shortcutphi-Ctº

θ> 5 ºC

Inventories of Anthropogenic CO2 (Pg C)

0.0

1.0

2.0

3.0

4.0

5.0

-80 -60 -40 -20 0 20 40 60 80Latitude

TrOCAIPSLTTDCFC-shortcutphi-Ctº

Inventories of Anthropogenic CO2 (Pg C)

θ< 5 ºC

Inventories of Anthropogenic CO2 (Pg C)

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

10.0

11.0

-80 -60 -40 -20 0 20 40 60 80Latitude

TrOCAIPSLTTDLee et al. (2003)phi-CtºCFC-shortcut

METHOD Total Inventory (Pg C) Difference (%)

∆C* [Lee et al., 2003] 47 --

TTD 48 1%

TrOCA 49 4%

IPSL 65 39%

phi-CTº 55 16%

The latitudinal variability of the inventory trends are very similar for all five methods compared, and matches that in Lee et al. (2003) EXCEPT for the Southern Ocean (-5 Pg C lower on average).

Inventories of the θ>5 ºC layer are very similar (22-25 Pg C) but for the IPSL results (30 Pg C).

Inventories of the θ<5 ºC layer vary from 25 Pg C (TrOCA) to 36 Pg C (IPSL).

At a REGIONAL level:

• TTD yields the lowest inventory estimates (about -5 Pg C) for the North Atlantic equatorial and subtropical regions, mainly in the DWBC influence areas. Here, it seems to overestimate the mixing vs. advection of CFCs.

• TrOCA yields the lowest inventory estimates (average -4 Pg C) for the South Atlantic.

• φCTº tends to produce low values in the Nordic Seas.

CONCLUSIONSCONCLUSIONS

TrOCA MethodTrOCA Method [[Touratier et Touratier et al.al., 2004, 2006], 2004, 2006]

IPSL MethodIPSL Method [Lo [Lo Monaco et al.Monaco et al., , 2005]2005]

Cant = CT - Cbio - CTo,obs - Co

REF (1)

Cbio = 0.73 (O2o - O2) + 0.5 (AT - AT

o) (2)

O2o = O2

sat - k O2sat (3)

ATo(S) = 0.0685 PO + 59.787 S - 1.448 + 217.15 (± 5.5 µmol/kg, r2 = 0.96, n = 243) (4)

ATo (N) = 42.711 S + 1.265 + 804.6 (± 9.3 µmol/kg, r2 = 0.92, n = 297) (5)

CTo,obs(S) = -0.0439 PO + 42.79 S - 12.019 + 739.83 (± 6.3 µmol/kg, r2 = 0.99, n = 428) (6)

CTo,obs (N) = 10.69 S + 0.306 NO + 1631.6 (± 9.2 µmol/kg, r2 = 0.79, n = 364) (7)

CoREF = [CT - Cbio - CT

o,obs]REF = -51 µmol/kg (8)

calculated CoREF in the North Atlantic Deep Water (NADW) detected in the South

Atlantic

φφCCTTºº Method Method [[Vázquez-Rodríguez et Vázquez-Rodríguez et

al.al., 2006 submitted], 2006 submitted]

C*= CT - AOU/RC - 0.5 [AT-ATo+AOU (1/RN+1/RP)] - CT

eq (2)

satantdis

disant

CCCC

C/||1

*

Cdis = Cdis - Cdis = -φ Cant / |Cdis| (3)

(1)