OceanObs’09
Community White Paper Proposal
A global sea surface carbon observing system: assessment of sea surface CO 2 and air-sea
CO2 fluxes.
Ute Schuster, School of Environmental Sciences, University of East Anglia, Norwich, UK, NR4
7TJ, U.Schuster@uea.ac.uk, tel +44 1603 593763
Pedro M.S. Monteiro (pmonteir@csir.co.za),
Contributing authors
Chris Sabine (Chris.Sabine@noaa.gov), Dorothee C.E. Bakker (d.bakker@uea.ac.uk), Taro
Takahashi (taka@ldeo.columbia.edu), Rik Wanninkhof (Rik.Wanninkhof@noaa.gov), Bronte
Tilbrook (Bronte.Tilbrook@csiro.au), Andrew Lenton (andrew.lenton@locean-ipsl.upmc.fr),
Yukihiro Nojiri (hge02674@nifty.com), Maria Hood (m.hood@unesco.org),
+ anybody who contributes
1) why sea surface carbon measurements are important
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One of the important factors in the changing atmospheric CO2 inventory over the
next 100 years will be the adjustments in the ocean uptake of anthropogenic CO2 as
well as uncertain changes in the natural CO2 exchange flux variability on seasonal,
interannual, through decadal time scales. These have implications in terms of our
understanding of the coupled ocean – atmosphere systems as well as for CO2
emission mitigation strategies.
carbon VOS has been very successful in the past 20 years in giving us global picture
of decadal averaged CO2 ocean sources and sinks.
will require a globally integrated observational strategy including VOS, moorings,
buoys, stations, etc. (link to other white papers).
to reduce the uncertainty of CO2 air-sea fluxes on regional and ocean basin scales,
and ultimately on a global scale to better than ± 0.2 Pg C yr-1 (~ 10%),
To resolve regional and global interannual and seasonal variability will be the
challenge for the next 10 years, for which a higher resolution of measurements is
needed.
To create a sustained observation system to monitor trends and variability in sea
surface partial pressures of carbon dioxide (pCO2) in response to climate variability
and increasing atmospheric CO2 burden, and to determine the drivers of regional
variability, the sensitivity of these drivers to climate change.
To provide observations to constrain and validate hindcast and forecast numerical
models, including those used to constrain the ocean-land partitioning of carbon.
2) the current state and achievements of the sea surface carbon observing network
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highlighting all scientific achievements based on the measurements; maybe
subsectioned into ocean basins;
will include a global map of carbon VOS lines;
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will include photos of ships and instruments;
maybe a table of the VOS lines with frequency of measurements (maybe in an
appendix?);
repeat measurements along set routes, aiding to elucidate seasonal to interannual
variability
3) the current limitations of the global sea surface carbon observing network
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uncertainties in flux estimates are still too high to resolve global interannual
variability
air-sea flux estimates are currently still too dependent on wind stress;
currently not sufficient additional parameters are measured to resolve the
biogeochemical/physical causes for determined variability of sea surface pCO2
and air-sea flux of CO2;
current costs are too high, to extent the measurement network to a sufficiently
high number of ships (whatever that number is);
to achieve high accuracy and precision, current instrumentation requires a lot of
maintenance, and highly trained personnel;
too dependent on high ship traffic to achieve low uncertainties;
cannot cover all ocean basins, especially not where not commercial shipping
routes are
4) Strategy for the next 10 years
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A global network of carbon measurements on ships, gliders, moorings, Carioca
buoys, floats etc…, including strategy which is common to all, to aim at an
uncertainty of less than 15 %;
strategies covering ocean and coastal domains (based on the SOCAT groups:
North Atlantic + Arctic, North Pacific, Tropical Ocean, Indian Ocean, Southern
Ocean (with Atlantic, Pacific and Indian sections), Coastal systems; includes
strategies specific to an area/region/ocean basin; eg: in some instances it may be
possible to instrument more ships but in others eg: Southern Ocean it may require
a combination of more GAW stations, VOS, buoys, and gliders to resolve the
winter fluxes
build on successes and provide possible solutions to resolve limitations;
density of lines needed
frequency of measurements needed
collaboration with the shipping industry (starting through SCOR)
further development of sensors
collaboration with measurers on buoys, moorings, floats, etc.
5) Synthesis.