Post on 19-Mar-2016
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Joos, Plattner, Stocker, Körtzinger, and Wallace (2003). EOS 84, 197-204.
WP10The motivation
Electrochemical sensor(Seabird SBE 43/IDO)
Optode sensor (Aanderaa 3830)
Measurement range:120% of surface saturation
Initial accuracy:2% of saturation
Response time:6 s (e-folding time)
Measurement range:0-120% of surface saturation(0-500 µM)
Precision:<1 µM (0.4%)
Initial accuracy:8 µM or 5% (whichever is greater)
Response time:25 s (e-folding time)
Principle: Life time based dynamic fluorescence quenching
Principle: Clark-type polarographic membrane sensor
UW floats(S. Riser)
WP10The technological situation
Körtzinger et al. (2005). High-quality oxygen measurements from profiling floats: A promising new technique.J. Atm. Ocean. Techn. 22, 302-308.
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Number of datapoint
Oxy
gen
[µM
]
2
3
4
5
6
7
8
9
10
Tem
pera
ture
[°C
]
Oxygen, measuredOxygen, calculatedTemperature
Sensor in air
292.5
293.0
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294.0
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295.0
295.5
296.0
296.5
0 100 200 300 400 500 600
Day
Oxy
gen
conc
entra
tion
(µm
ol L
-1)
35.99
36.00
36.01
36.02
36.03
36.04
36.05
36.06
36.07
36.08
S,T,
p (k
g m
-3)
OxygenIn-situ density
p = 1799.2 ± 0.2 dbar
Tengberg, Körtzinger et al. (2006). Evaluation of a life time based optode to measure oxygen in aquatic systems. Limnol. Oceanogr. Methods 4, 7-17.
Drift check possible through air measurements
High long-term stability
O2 = 295.0 ± 0.7 µmol/L
WP10The technological situation
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Julian day
Oxy
gen
inve
ntor
y (0
-140
0 m
) [m
ol O
2 m-2 ]
0
200
400
600
800
1000
1200
1400
1600
M
ixed
laye
r dep
th (m
)
Oxygen inventory
Mixed layer depth
2003 2004
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Oxy
gen
inve
ntor
y 0-
1400
m (m
ol O
2 m-2 )
0
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290 295 300 305 310 315 320 325Oxygen (mmol m-3)
Pre
ssur
e (d
bar)
Oct. 5, 2003 (profile 4)Oct. 26, 2003 (profile 7)Nov. 2, 2003 (profile 8)Dec. 7, 2003 (profile 13)Dec. 28, 2003 (profile 16)Feb. 8, 2004 (profile 22)Feb. 22, 2004 (profile 24)Mar. 21, 2004 (profile 28)Apr. 4, 2004 (profile 30)Apr. 11, 2004 (profile 31)
A
C
B
Körtzinger et al. (2004). The ocean takes a deep breath. Science, 306, 1337.
quasi-stationary float
WP10The science showcase
PROVOR-DO PROVOR-CarboOcean
Oxygen sensor Oxygen sensor
PIC sensor
• March 2007: Delivery of prototype 2 floats from MARTEC company
• Spring 2007: Testing of floats (vibration, tank, basin) at IFREMER
• Spring/summer 2007: Sea trials of floats
• February 2009: field study with deployment of 2 floats (77 and 90 profiles, resp.)
• November 2006: Delivery of 2 prototype floats from MARTEC company
• Nov./Dec. 2006: Testing of floats (vibration, tank, basin) at IFREMER
• February 2007: Deployment during R/V Poseidon Cruise 348 by IFM-GEOMAR north of the Cape Verde archipelago
• February 2008: field study with deployment of 4 floats (all still active in Oct. 2009)
WP10The technological development
PROVOR CTS3 DO PROVCARBON
Final proof-of-concept field experiment using 6 newly developed oxygen floats is successfully running since Feb. 2008
All four PROVOR CTS3 DO float still active after 73-83 profiles PROVCARBON float stopped after 77 and 90 profiles, resp. Evaluation of field experiment data ongoing
WP10The field experiment
Oxygen time-series
Example: 90 profiles by float WMO #6900632 showing upwelling dynamics off Mauritania
active coastalupwelling of low-oxygen waters
Sub-surface respiration of organic matter
produced in upwelled waters
WP10The scientific potential of an ARGO O2 observatory
Estimation of the wind speed dependence of the gas transfer coefficient (k660) from three years of data in the Labrador Sea convection region
Kihm and Körtzinger, in prep.
WP10The scientific potential of an ARGO O2 observatory
Estimation of sub-surface oxygen utilization rates from three years of data in the Labrador Sea convection region
Kihm and Körtzinger, in prep.
2003 20042005
WP10The scientific potential of an ARGO O2 observatory
Keeling, Körtzinger, and Gruber (2010). Ocean deoxygenation in a warming World. Annual Review of Marine Science. 2, in press.
WP10The emerging global picture of O2 trends
The latest OMZ trends ...
Model vs. observations: A16N
Simulated and observed decadal variability are of similar order
Internal variability of a specific year is up to 20 μmol/kg
Observed O2-decrease from 1993 and 2003 is 30 μmol/kg
Simulated internal varia-bility is up to 45 μmol/kg
Impact of the Mt. Pinatubo eruption is negligible
Johnson et al. (2007)
IntroductionMethodsResultsCaveats/closing thoughts
The present oceanThe future oceanLong-term changes
Frölicher et al. (2009, GBC)
Large local O2-decrease in thermocline of the North Pacific and the Southern Ocean (due to reduced air-sea gas exchange and reduced ventilation, partly
compensated by biological processes)
O2-decrease in deep North Atlantic (more efficient PO4 utilization due to lower ventilation)
O2-increase in tropical thermocline (large decrea-se in export production, possibly reduction in water mass ages)
Regional maximum O2 decrease/increase
Depth Depth
Frölicher et al. (2009, GBC)
IntroductionMethodsResultsCaveats/closing thoughts
The present oceanThe future oceanLong-term changes
Global decrease in dissolved oxygen
Total O2 content is projected to decrease by 5.9 Pmol (2.6%) by year 2100.
Solubility-driven changes are responsible for at least 50% of the total decrease.
Additional O2 loss resulting from change in ocean circulation and biology
Frölicher et al. (2009, GBC)
solubility-driven
stratficiation
IntroductionMethodsResultsCaveats/closing thoughts
The present oceanThe future oceanLong-term changes
Johnson, K.S., W.M. Berelson, E.S. Boss, Z. Chase, H. Claustre, S.R. Emerson, N. Gruber, A. Körtzinger, M.J. Perry, and S.C. Riser (2009). Observing biogeochemical cycles at global scales with profiling floats and gliders: prospects for a global array, Oceanography, 22, 217-225.
WP10The BGC community is starting to embrace ARGO