Diapositiva 1

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pCO2 measurements at sea
SUMMER SCHOOL Measurement methods for the carbon
system and related tracers in sea water
SUMMARY
INTRODUCTION
PRINCIPLE
SAMPLING
Air intake
Water intake
EQUILIBRATOR
DRYING SYSTEM
DETECTOR SYSTEM
CALIBRATION
PROCEDURES
DATA LOGGING
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pCO2 measurements at sea
SUMMER SCHOOL Measurement methods for the carbon
system and related tracers in sea water
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pCO2 measurements at sea
SUMMER SCHOOL Measurement methods for the carbon
system and related tracers in sea water
The exchange of carbon, F
mmol m-2 day-1 mol m-2 year-1
F S k (pCO2sea-pCO2atm)
-15/15 mol m-2 year-1
CO2 gradient, (pCO2sea - pCO2atm)
CO2 solubility, S (mol L-1 atm-1), according
to Weiss (1974)
f(SST,SSS)
Transfer velocity, k (cm h-1), the constants more
commons are Liss
and Merlivat (1986) and Wanninkhof et al. (1992)
f(wind speed)
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pCO2 measurements at sea
SUMMER SCHOOL Measurement methods for the carbon
system and related tracers in sea water
R/V METEOR A lab view during the intercomparison
exercise of underway pCO2 systems
SHIP OF OPPORTUNITY RO-RO LAUDACE
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pCO2 measurements at sea
SUMMER SCHOOL Measurement methods for the carbon
system and related tracers in sea water
FLOATING EQUILIBRATOR SYSTEM
photograph by Bruno Delille
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pCO2 measurements at sea
SUMMER SCHOOL Measurement methods for the carbon
system and related tracers in sea water
STE ANNA FIX STATION Antwerpen, on the Scheldt
estuary
photograph by Alberto Vieira Borges
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pCO2 measurements at sea
SUMMER SCHOOL Measurement methods for the carbon
system and related tracers in sea water
FLOATING DOCK Mesocosm experiment at Bergen
Marine Station
photograph by Bruno Delille
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pCO2 measurements at sea
SUMMER SCHOOL Measurement methods for the carbon
system and related tracers in sea water
Chemical Oceanography Unit of University of
Liege (Belgium)
photograph of Michael Frankignoulle
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pCO2 measurements at sea
SUMMER SCHOOL Measurement methods for the carbon
system and related tracers in sea water
Skogafoss equilibrator
Courtesy Y. Nojiri
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pCO2 measurements at sea
SUMMER SCHOOL Measurement methods for the carbon
system and related tracers in sea water
PYXIS EQUILIBRATOR
Courtesy Y. Nojiri
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pCO2 measurements at sea
SUMMER SCHOOL Measurement methods for the carbon
system and related tracers in sea water
GASPAR Underway pCO2 system of Instituto de
Investigacións Mariñas
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pCO2 measurements at sea
SUMMER SCHOOL Measurement methods for the carbon
system and related tracers in sea water
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pCO2 measurements at sea
SUMMER SCHOOL Measurement methods for the carbon
system and related tracers in sea water
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pCO2 measurements at sea
SUMMER SCHOOL Measurement methods for the carbon
system and related tracers in sea water
GASPAR scheme
Air intake
At the bow of the ship
Record ships navigation and meteorological data
are recorded to confirm the quality of the air
Relative winds higher than 2 ms-1
Water intake
Record the water intake and equilibrator
temperatures
VERY IMPORTANT

• Minimum temperature difference between
• inlet and equilibrator

• High flow rate

• Close the passage of seawater

• Employ insulating material

?Tlt 1ºC
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pCO2 measurements at sea
SUMMER SCHOOL Measurement methods for the carbon
system and related tracers in sea water
16
pCO2 measurements at sea
SUMMER SCHOOL Measurement methods for the carbon
system and related tracers in sea water
EQUILIBRATORS
Bubble equilibrator
Laminar flow equilibrator
MULTISTAGE EQUILIBRATOR
Shower equilibrator
Bead equilibrator
Atmospheric pressure
Equilibration takes 2-3 minutes
RECOMENDATIONS
Vent, silicon grease
Biofouling, routine cleaning
Clogging, sediment trap
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pCO2 measurements at sea
SUMMER SCHOOL Measurement methods for the carbon
system and related tracers in sea water
EQUILIBRATOR SYSTEM OF GASPAR
BUBBLE EQUILIBRATOR
LAMINAR FLOW EQUILIBRATOR
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pCO2 measurements at sea
SUMMER SCHOOL Measurement methods for the carbon
system and related tracers in sea water
GASPAR scheme
EQUILIBRATOR
Multistage equilibrator bubble and
laminar flow equilibrator
Equilibration chamber works at atmospheric
pressure
Seawater drain by gravity
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pCO2 measurements at sea
SUMMER SCHOOL Measurement methods for the carbon
system and related tracers in sea water
20
pCO2 measurements at sea
SUMMER SCHOOL Measurement methods for the carbon
system and related tracers in sea water
21
pCO2 measurements at sea
SUMMER SCHOOL Measurement methods for the carbon
system and related tracers in sea water
DETECTOR SYSTEM
Gas chromatography, not a compact intrument
Spectophotometer, robust and cheap but with
stability problems
Infrared gas analyzer, most common gas analyzer
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pCO2 measurements at sea
SUMMER SCHOOL Measurement methods for the carbon
system and related tracers in sea water
DETECTOR SYSTEM
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pCO2 measurements at sea
SUMMER SCHOOL Measurement methods for the carbon
system and related tracers in sea water
GASPAR scheme
Detector system
LICOR 6262
CO2 and H2O free-air in the reference cell
External air filter
Correct use of the scrubber tube
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pCO2 measurements at sea
SUMMER SCHOOL Measurement methods for the carbon
system and related tracers in sea water
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pCO2 measurements at sea
SUMMER SCHOOL Measurement methods for the carbon
system and related tracers in sea water
CALIBRATION
To adjust the zero and the span potentiometers in
the LICOR
RECOMENDATIONS
Organization Number of gas standard Durantion
and interval of calibration
CMDL/NOAA
4
each hour
Small bottles are the best option
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pCO2 measurements at sea
SUMMER SCHOOL Measurement methods for the carbon
system and related tracers in sea water
GASPAR scheme
CALIBRATION
2 gas standard CO2-free gas CO2 standard
concentration, 375 ppm
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pCO2 measurements at sea
SUMMER SCHOOL Measurement methods for the carbon
system and related tracers in sea water
28
pCO2 measurements at sea
SUMMER SCHOOL Measurement methods for the carbon
system and related tracers in sea water
CYCLE OF ANALYSES (calibration 1 hour)

• Wanninkhof and Thoning, 1993
• (recording the average of measurements over a 1
  min)
• Ambient air concentration of CO2 22 min
• CO2 in air from the equilibrator 23 min
• 3 calibration gases for 5 min each
• Discard the results from the first 3 min

• GASPAR
• (recording a filtered average of measurements
  over a 1 min)
• Atmospheric air concentration of CO2 5 min
• CO2 in air from the equilibrator 55 min
• 2 calibration gases for 5 min each
• Discard the results from the 15 seconds

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pCO2 measurements at sea
SUMMER SCHOOL Measurement methods for the carbon
system and related tracers in sea water
30
pCO2 measurements at sea
SUMMER SCHOOL Measurement methods for the carbon
system and related tracers in sea water
FUTURE GOALS
MORE SHIPS
GREATER EFFICIENCY
LOWER COST IR ANALYZERS
COMMON REPORTING FORMATS
DATA SHARING
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pCO2 measurements at sea
SUMMER SCHOOL Measurement methods for the carbon
system and related tracers in sea water