1. Interannual Variability in the Extratropical Ocean Carbon System
Scott Doney (WHOI)
-Ubiquitous!!
-Physical climate modes
-Mechanisms & climate change
-New approaches & experimental designs
Hawaii Ocean Time-Series
Dore et al. (2002)

2. Interannual Variability in Global Carbon Cycle
Atmospheric CO2 growth rate
Francey
-Ocean sequesters ~30% of fossil fuel CO2
-Variability dominated by land sinks but role for the oceans
-Primary global signal associated with ENSO events

3. Equatorial Pacific El Niño : 0.2-0.4 PgC/y Non El Niño : 0.7-0.9 PgC/y
Average: ±0.2 PgC/y
-Dense time/space coverage
-Agreement among field data, ocean models & “top-down” atmospheric estimates
ocean model
atmosphere
data
Bousquet et al. (2000)
Le Quere et al. (2000)
(also Obata et al. 2003)
Feely et al. (2003)

4. Natural Climate Modes NAO: North Atlantic Oscillation
Surface Pressure Anomaly
NAO: North Atlantic Oscillation
PDO: Pacific Decadal Oscillation
AAO: Antarctic Oscillation
-Shift of mass from subpolar lows and subtropical highs
-Changes in winds, SST, ocean convection, freshwater flux, …
-”Intrinsic” atmospheric variability (ocean, stratosphere)
-Tropical-extratropical interactions
NAO
Wang and Schimel (2003)

5. Regional Spatial Patterns
-Modes expressed on regional (sub-basin) scales with significant cancellation (dipole pattern)
-Historical and future climate change appear to project onto natural modes
-Spatial patterns may evolve with time
Wang and Schimel (2003)
-0.6
Correlation
+0.8
models
NAO Index
obs.
1900
1950
2000
2050

6. Subtropical North Atlantic
Mixed Layer
Negative NAO =>
+WML
-SST
+entrainment
+production
+CO2 uptake
Extrapolate to subtropical gyre =>
±0.2 PgC/y
whole basin =>
±0.3 PgC/y
CO2 uptake
Entrainment
Transport
Production
Gruber et al. (2002)

7. Pacific Decadal Oscillation
ML Anomaly
Wang & Schimel (2003) + +
PDO
Depth
Integrated
Chlorophyll
Subtropical
nutrient limited prod.
+ML => +Chlorophyll
+ Production
Subpolar/Polar
light limited prod.
-ML => +Production
multiple impacts on higher trophic levels (e.g. zooplankton, fisheries, mammels)
Karl et al. (2001)
Hare & Mantura (2000)

8. Climate Change Response
productivity
Sarmiento et al. (submitted)
-Regional climate change signals
-Surface warming, high latitude freshening, increased stratification, reduced mixed layer depths & sea-ice
-Productivity lower in subtropics, higher in subpolar

9. Multi-Century Coupled Carbon/Climate Simulations
+1.5
14.1
-1.5
13.6
Surface Temp.
Net CO2 Flux (Pg C/yr)
year
200
Fung, Doney, Lindsay & John
-Fully prognostic land/ocn BGC and carbon/radiation
-“Stable” carbon cycle and climate over 200y
-Projection of climate change on natural modes
-Detection & attribution

10. Variability Mechanisms
Particle
export
Air-sea
flux 1 .3 10 3 .1
Fresh-
water
mol C/m^2
-Regions of high variability in North Atlantic & Pacific, tropics and Southern Ocean
-Mechanisms differ across regions
Fung, Doney, Lindsay & John

11. Atmospheric Dust Deposition
-Significant interannual variability, particularly in the North Atlantic
-Driven mostly by atmospheric transport, not sources
-Largest fraction is synoptic, within month variability
(standard deviation/mean)
Mahowald et al. (2003)

12. Iron
flux
Zonal Anomalies
Air-sea
CO2 flux
N2 Fixation
Doney, Dusenberry, Moore & Mahowald

13. SeaWiFS Ocean Color Data (1997-2003)

14. Coherent Regional-Scale Patterns
SeaWiFS Monthly Anomaly
SeaWiFS Monthly Anomaly
Oct. 1998
April 2000

15. Antarctic Circumpolar Wave
Le Quere et al. (2002)
-Positive/negative physical anomalies propagate around southern ocean with 8-10 year time-scale
-Ocean color variability appears coherent across basin
-Differential regional biological responses to mixed layer depth changes depending on light versus nutrient limitation

16. New Technology & Observational Paradigms
time
space
Local
Globe
Ocean
Basin
Regional
(500 km)
Centuries
Decadal
Inter-annual
Seasonal
Daily
Remote
sensing
Hourly
Process Studies
Repeat
Sections
Surface transects
Floats/drifters
Ocean Observatories
Ship
Time-Series
Moored
Atm. CO2O2/N2
New Technology & Observational Paradigms

17. Conclusions -Common feature of almost all ocean time-series
-Regional time-space structured by climate modes & biology
-Natural experiments for studying climate change response
-Require more spatially “extensive” design for ocean observation
Acknowledgements
J. Dusenberry & S. McCue WHOI K. Lindsay NCAR
NSF and NSF/ONR NOPP
CCSM & the NCAR CSL

18. Global & Extratropical Variability
LeQuere: ±0.4 (70% Eq. Pac.)
Obata: ±0.23 (>50% Eq. Pac.
~30% Southern)
-Only partial reconciliation with atmosphere inversions
-Poor data coverage outside of equatorial Pacific
LeQuere et al. (2000)
Obata et al. (2003)
Bousquet et al. (2003)

20. Regional Spatial Patterns
Wang and Schimel (2003)
-0.6
Correlation
+0.8
-0.6
Correlation
+0.8
-Modes expressed on regional (sub-basin) scales with significant cancellation (dipole pattern)
-Historical and future climate change appear to project onto natural modes
-Spatial patterns may evolve with time

21. Monthly SeaWiFS Ocean Color Anomalies
standard deviation
standard deviation/mean

22. Equatorial Pacific -DIC supply (dominant) & export out of phase
physics
-DIC supply (dominant) & export out of phase
-General agreement among field data, ocean models &
“top-down” atmospheric estimates
-But what about the extratropics?
export
air-sea
flux
Obata et al. (2003)
Bousquet et al. (2000)
ocean model
atmosphere
data
Le Quere et al. (2000)
Obata et al. (2003)

23. Antarctic Circumpolar Wave
-Ocean response to annular mode in the atmosphere
-Different regional biological responses to mixed layer depth changes
-Air-sea CO2 flux correlated with wind stress/speed
Le Quere et al. (2002)
Wind Stress
& CO2 flux
Anomalies
+0.1
-0.1
Obata et al. (2003)

24. Global Carbon Cycle -Ocean sequester ~30% of fossil fuel CO2
-Human perturbations overlay large natural background C cycle
-Climate responses and feedbacks of ocean C sink not well known
Human perturbations due to fossil fuel combustion and land-use change occur on top of a large natural background cycle coupling the land, atmosphere, and ocean
-Ocean now sequestering ~30% of fossil fuel CO2
-Human perturbations overlay large natural background C cycle
-Climate responses and feedbacks of ocean C sink not well known
-Quantitative understanding needed of mechanisms controlling biological productivity
Doney and Schimel (2001)

25. Physical & Biological Controls
pCO2 = f(Temp., Salinity, DIC, Alkalinity)
(+)
Net Community Prod.
Winter
mixed
layer
Circulation
Light
Nutrient/
DIC Supply
Export
Winds, Heat &
Freshwater Fluxes
Dust/iron
CO2 O2
Remineralization
Regenerated Prod.

26. Community Structure & Higher Tropic Levels
-Impacts on both biomass and species competition
-Multi-decadal “regime shifts” integrating higher frequency climate variability
Time series of C. finmarchicus abundance from (a) the North Sea and (b) the Gulf of Maine/Scotian Shelf region. Time
series are based on Continuous Plankton Recorder (CPR) data collected for C. finmarchicus from the North Sea since the late 1940s
and from the Gulf of Maine/Scotian Shelf region since the late 1950s. Data from the Gulf of Maine are indicated by circles and
from the Scotian Shelf by triangles. Methods of sample collection and processing have been described by Hardy (1939); Colebrook
(1975), and Jossi and Goulet (1993). (c) Time series of the NAO index from 1955 to The NAO index is the mean difference,
expressed as an anomaly from the long-term mean, in atmospheric pressure during winter between the subtropical high pressure
system of the North Atlantic, measured in Lisbon, Portugal, and the subpolar low pressure system, measured in Stykkisholmur,
Iceland (Hurrell, 1995). (d) Cross-correlation analyses between C. finmarchicus abundance and the NAO index. Results of the analyses
of data from the North Sea are indicated by rectangles and from the Gulf of Maine during 1961–1989 and 1961–1999, respectively
by triangles and circles. (e) Regression between C. finmarchicus abundance in the North Sea and the NAO index with no time lag.
(f) Regression between C. finmarchicus abundance in the Gulf of Maine and the NAO index with a time lag of 4 years, 1961–1989
(dashed) and 1961–1999 (continuous).
Greene et al. 2003
Chavez et al. 2003

27. Climate Modes & Change Change

28. SeaWiFS Ocean Color Data (1997-2003)