GLOBAL CLIMATE AND PACIFIC FISHERIES

Air-temperature (global)

PDO

Atmospheric CO2 anomalies

Fisheries landing in Peru

Chavez et al. (2003)

DECADAL CHANGES IN THE NORTH PACIFIC

EL VIEJO (positive PDO)

Chavez et al. (2003)

Decadal variability in the carbon cycle and biogeochemistry of the North Pacific

Highlights from the NOAA/GCP/PICES synthesis and modeling workshop

Nicolas GruberDepartment of Atmospheric and Oceanic Sciences & IGPP, UCLA

UNDERSTANDING NORTH PACIFIC CARBON CYCLE CHANGES

Acknowledgements:

C. L. Sabine, R. A. Feely, S. C. Doney, R. M. Key, J. L. Sarmiento, A. Kozyr and all workshop participantsNOAA, Global Carbon Project and PICES for funding

Outline

• Introduction: Why studying North Pacific carbon cycle changes?

• Decadal changes in surface pCO2: observations and mechanisms

• Decadal changes in ocean interior properties

• Anthropogenic climate change: Detection and Attribution

Surface ocean pCO2 observations

Takahashi et al.

Mechanisms for pCO2 change:

pCO2 = f (T,S,DIC,Alk)

∆pCO2 =∂pCO2

∂T∆T

Temperature1 2 4 3 4

+∂pCO2

∂S+

∂pCO2

∂DIC∂DIC

∂S+

∂pCO2

∂Alk∂Alk∂S

⎛ ⎝ ⎜

⎞ ⎠ ⎟ ∆S

Salinity1 2 4 4 4 4 4 4 4 4 3 4 4 4 4 4 4 4 4

+∂pCO2

∂DIC∆sDIC

DIC1 2 4 4 3 4 4

+∂pCO2

∂Alk∆sAlk

Alk1 2 4 4 3 4 4

At Station ALOHA (Hawaii)

Process: pCO2 Trend (1988-2002)[ppm/yr]

쾆 emperature -0.3² Salinity 0.4

D쾠 IC 2.1쾠Alk 0.4

Observed trend 2.5? .1

mostly driven by Cant

also by ∆Salinity

Data from Keeling et al. (2004)

Keeling et al. (2004)

Mechanisms for salinity changes:

LOCAL-SCALE

Sur

face

sal

inity

Rai

nfal

l

LARGE-SCALE (σθ=25.5 from ECCO)

Mea

n sa

linity

Pen

tada

l ano

mal

y

(1997-2001) minus (1992-1996)

Brix (unpublsihed) Dore et al. (2003)

Outline

• Introduction: Why studying North Pacific carbon cycle changes?

• Decadal changes in surface pCO2: observations and mechanisms

• Decadal changes in ocean interior properties

• Anthropogenic climate change: Detection and Attribution

SUMMARY OFNORTH PACIFIC AOU CHANGES

Kumamoto

Alaskan Gyre (σθ=27.0)0.3±0.1 µmol/kg/yr, 1952-2000Andreev and Watanabe (2002)

from trends to variability spectrumdistinct spatial heterogeneityvariations occur on all time-scaleslinear trend models inadequate!

Outline

• Introduction: Why studying North Pacific carbon cycle changes?

• Decadal changes in surface pCO2: observations and mechanisms

• Decadal changes in ocean interior properties

• Anthropogenic climate change: Detection and Attribution

Part of the oxygen changes are likely due to global warming

BUT

Magnitude not yet large enough relative to natural variability to detect signal

Implications for anthropogenic DIC

We need to separate the DIC changes in the natural carbon pool into into an intrinsic component, ∆DICintrinsic, and a climate change component, ∆DICclimate change, in order to determine the anthropogenic CO2 balance of the ocean!

∆DIC = ∆DICant +∆DICnatclimate change +∆DICnat

intrinsic

∆O2 = +∆O2natclimate change +∆O2nat

intrinsic

Oxygen can be of very helpful for this!

Conclusions

• First initial steps: Many challenges, few answers yet

(much more to come, >15 publications planned)

• Good progress toward the integration of observations

and models.

• Data synthesis and modeling activities need to be

continued… (annual workshops, etc)

The End.

Role of SST variations on pCO2 variability

McKinley (pers. comm.)

Tropics: pCO2 anomalies are DIC controlledSub-tropics: pCO2 anomalies are SST controlledSub-polar gyres: pCO2 anomalies are DIC controlled

Decrease in sub-arctic Pacific

Small decrease in subtropical Pacific

Increase in marginal Seas and Tropical Pacific

Productivity changes?

Winter Summer

NP

AC

CE

NTR

AL

GY

RE

0.0

0.1

0.2

0.3

20

40

60

0'70 '80 '90 '00year'70 '80 '90 '00year

EA

STE

RN

PA

CIF

IC 1

37°E

Phosphate

ChlorophyllChlorophyll

Phosphate

Watanabe et al. (submitted)

Karl et al. (2000)

LAND-OCEAN PARTITIONING OF ANOMALOUS CO2 FLUXES

LeQ

uere

et a

l. 20

03)