Transcript Monday_5_Keeling presentation for ICESOCC.pptx

What atmospheric O2
measurements can tell us about
the Southern Ocean
Ralph Keeling
Scripps Institution of Oceanography
O2 and CO2 coupling
Land
Plants
Industry
Oceans
CO2 + CO32-+ H2O ↔ 2 HCO3-
O2 and CO2 coupling
Land
Plants
Industry
Oceans
CO2 + CO32-+ H2O ↔ 2 HCO3-
Time series measurements of O2 and CO2
δ(O2/N2) =
(O2 / N 2 ) sample  (O2 / N 2 ) reference
(O2 / N 2 ) reference
4.8 per meg ~ 1 ppm
Atmospheric potential oxygen
ΔCO2 = F – O – B
ΔO2 = -1.4F + 1.1B +Z
B
F
ΔAPO = ΔO2 + 1.1ΔCO2 = -0.3F -1.1O + Z
“Atmospheric
Potential
Oxygen”
Z
Z
O
Ocean CO2 uptake:
H2O + CO2 + CO3=
↔ 2HCO3-
Seasonal air-sea O2 flux
Trend in APO
APO ≈ O2 + 1.1 CO2
Global O2network
Scripps O2 program
Scripps O2 Program Elements
Flask network, 10 stations
Continuous measurements at La Jolla
Measure CO2, O2/N2 ratio and Ar/N2 ratio
Methods development
Calibration facility
Project Website: ScrippsO2.ucsd.edu
HIPPO airborne campaign
5 campaigns
Jan 2009 – Sept 2011
HIPPO Campaign Results
−200
−220
Cape Grim Observatory, Tasmania
APO [per meg]
−240
−260
−280
−300
Palmer Station, Antarctica
−320
2009
2009.5
2010
2010.5
2011
2011.5
2012
40
30
HIPPO Obs Adjusted Fit = 37.3 per meg
APO [per meg]
20
10
0
−10
−20
−30
−40
J
F
M
A
M
J
J
A
S
O
N
D
Using HIPPO to challenge ocean models
Thesis by Jonathan Bent (2014)
Contrib. to APO [per meg]
30
ACTM GK01
TM3 GK01
TM3 MOM4
20
10
0
−10
−20
−30
Contrib. to APO [per meg]
30
J F M AM J J A S O N D
J F M AM J J A S O N D
TM3 NEMO−PISCES−T
TM3 NEMO−CNTRL
J F M AM J J A S O N D
J F M AM J J A S O N D
J F M AM J J A S O N D
TM3 NEMO−WSTIR
20
10
0
−10
−20
−30
Contrib. to APO [per meg]
30
TM3 CCSM3
J F M AM J J A S O N D
TM3 CESM
20
10
0
Observ.
APO
O2 cont.
CO2 cont.
N2 cont.
−10
−20
−30
J F M AM J J A S O N D
J F M AM J J A S O N D
Oxygen Concentration (per meg)
How stable is the APO amplitude year-to-year?
100
Cape Grim (41°S)
0
-100
1990
1992
1994
1996
1998
2000
2002
2004
2006
2008
2010
2012
Continuous measurements of O2 at Trinidad, CA
From Lueker et al., Biogeosciences 2004
Measurements of Ar/N2
Quantifying global ocean heat content changes
Ar/N2 (per meg)
O2/N2 (per meg)
Time series at Palmer Station
Some key question
1) How well can current ocean models duplicate
climatological APO cycles? How does performance in
APO relate to other metrics?
2) How stable are cycles from year to year? How do
changes relate to changes in other metrics?
3) How can we assimilate APO data along with CO2
data and other data to resolve changes in the ocean
carbon cycle, both globally and regionally?
4) How can we use Ar/N2 data to best challenge ocean
models?
Future needs and opportunities
1) Restore time series of vertical atmospheric profiles in
O2/N2, CO2, and related tracers over the Southern
Ocean (including N2O).
2) Instrument key sites (e.g. Palmer Station, Cape Grim,
Macquarie, Amsterdam) with continuous
measurements.
3) Develop analyzers with improved long-term stability
(to reduce need for calibration gases).
4) Need complementary ocean measurements, with
year-round coverage. Summer “intensives” not be very
valuable in constraining carbon balance.