The Global Ocean Carbon CycleRik Wanninkhof, NOAA/AOML

Annual OCO review, June 2007:

Celebrating Our Past, Observing our Present, Predicting our Future: Ocean

Observations as a Key to Global Understanding.

“Jean Baptiste Fourier is credited with the discovery in his essay in 1827 that gases in the atmosphere might increase the surface temperature of the Earth” Wikipedia

The NOAA Carbon groups highlight:180 years of greenhouse gas research

NOAA highlights 200 years of science, service, and stewardship.

0

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1950 1960 1970 1980 1990 2000 2010

From ESRL_CMD

ppm/yr Maona Loappm/yr global

Year

The Overriding questions:

8 Pg C/yr released to the atmosphere ≈ 4 ppm increase4 Pg C/yr remains ≈ 2 ppm

Where does the remaining C go to?How does this change with time?What causes the changes?What are the ecosystem impacts?

CO2 Research Breakthroughs and New Questions Arising from OCO Sponsored Observations

Three major programs:1. Global Ocean CO2 inventories

2. Air-Sea CO2 fluxes from ships and moorings

3. Data Management, Analysis and Synthesis

4. (Coastal Carbon Research)

1. Global Ocean CO2 Inventories CLIVAR/CO2 Repeat Hydrography

Sponsors:NOAA/OCO, NSF/OCOParticipants: (NOAA funded) PMEL/AOML & CI’sMeasurements: CO2, hydro, nutrients, O2, CFC, SF6

I8S/I9NJanuary/April, 2007

Determine the Decadal Uptake of Anthropogenic CO2

Uncertainty: < 4 Pg/C/decade (out of an estimated 20 Pg C)Approach: Differencing with previous inventory estimatesFindings: Atlantic Pacific

25 ˚W 152 ˚W (mol m-2 yr-1)Northern Hemisphere 0.75 0.25 Southern Hemisphere 0.63 0.41

[Global estimate : 0.5 mol/m2/yr ]

But: ≠ 0 ≠ 0Ocean biogeochemistry not in steady state on decadal timescales

Research question: How to determine anthropogenic CO2?

∆ = Canthro + ∆CNatural + ∆CClimateEasternPacific 153 ˚W

Sabine et al. BAMS, 2007

I8S-I9N Re-occupation

Courtesy J. Bullister, PMEL

Research/observational needs- Inventories

- Need better estimates of changes in productivity and respiration- Need better estimates of ventilation and mixing - Use of transient

tracers, such as SF6

Bullister and Sonnerup, 2007

Objective: Constrain regional air-sea CO2 fluxes to 0.2 Pg C year

Findings: Global climatology estimate 30 % less than previous (Attributed to increased data and improved procedures, not

global change)Interannual variability ≈ 10 %

2. Surface water CO2 (Moorings and ship of opportunity)

R S M A S A O M L P M E L B I O S

( B B S R )

L D E O G O O S

( A O M L )

P a r t i c i p a n t s

T A / D I C

S a m p l e s

• B r o w n

• E x p l o r e r

• S k o g a f o s s

O l e a n d e r

A t l a n t i c E x p l o r e r

P a l m e r T S G

Q C + M a i n t e n a n c e T a s k s / S h i p s

• K a ’ i m i m o a n a

• C a s t i l l a

( C a p V i c t o r )

I n s t r u m e n t

D e v e l o p m e n t

D a t a

D e s t i n a t i o n

w w w . a o m l . n o a a . g o v /

o c d / g c c

w w w . p m e l . n o a a . g o v

/ c o 2 / u w p c o 2

w w w . l d e o . c o l u m b i a . e d u /

r e s / p i / C O 2 /

C D I A C

c d i a c . o r n l . g o v

P r o d u c t s F l u x M a p s Δ f C O 2 C o a s t a l O c e a n

p C O 2

h t t p : / / w w w . b b s r . e d u /

L a b s / c o 2 l a b / v o s . h t m l

Updated Air-Sea CO2 Flux Climatology

Uptake = 1.2 Pg C yearTakahashi et al. 2007

2. Models suggest a positive feedback in SO- Increasing winds- increasing upwelling-increasing pCO2w

Research question:Are there (positive) feedbacks?

Le Quere et al. Science May, 2007

1. North Atlantic observations suggest decreasing uptake

Collaborations in the North Atlantic and North Pacific

Started 2002, operational 2005 onwardsCourtesy D. Bakker CarboOcean

3. Data Management, Analysis and Synthesis

Production of flux maps [ F = k s ∆pCO2] North Atlantic and North Pacific synthesis LAS server for pCO2 data

- Takahashi climatology- Takahashi database- Original data

4. Coastal CO2:

What are the magnitudes and what causes the variations in CO2 fluxes in coastal region?

State Of the Carbon Cycle Report (SOCCR):

Northern Regions:Sink ≈ 0.2 Pg CSouthern regionsSource ≈ 0.2 Pg C

Coastal Survey Cruises

First Synoptic Measurements of CO2 along the coasts

Jiang et al., In Preparation

Determination of Seasonal Cycles of pCO2 in Coastal RegionsExcursions in pCO2 in coastal ocean >> open ocean

Coastal (upwelling) regions sensitive to ocean acidification

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200 400 600 800 1000 1200 1400

pCO2 (uatm)

Open Ocean

Coastal Ocean

Dissolution!

When pCO2 levels in seawater approach 1000 µatm dissolution of calcium carbonate (aragonite) will occur. Coastal upwelling regions such as the Peru upwelling system, the Arabian Sea, West Coast of US, and near bathymetric features in the US experience such levels in the surface water and could serve as test beds for ocean acidification research.

Thank you

And now to deflect the first question:

The New Yorker May 28, 2007