1 Oceanic sources and sinks for atmospheric CO 2 The Ocean Inversion Contribution Nicolas Gruber 1,...
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1 Oceanic sources and sinks for atmospheric CO 2 The Ocean Inversion Contribution Nicolas Gruber 1 , Sara Mikaloff Fletcher 2 , and Kay Steinkamp 1 1 Environmental Physics, ETH Zürich, Zurich, Switzerland. 2 NIWA, Wellington, New Zealand. RECCAP Meeting October 6, 2010
1 Oceanic sources and sinks for atmospheric CO 2 The Ocean Inversion Contribution Nicolas Gruber 1, Sara Mikaloff Fletcher 2, and Kay Steinkamp 1 1 Environmental
1 Oceanic sources and sinks for atmospheric CO 2 The Ocean
Inversion Contribution Nicolas Gruber 1, Sara Mikaloff Fletcher 2,
and Kay Steinkamp 1 1 Environmental Physics, ETH Zrich, Zurich,
Switzerland. 2 NIWA, Wellington, New Zealand. RECCAP Meeting
October 6, 2010
Slide 2
2 Air-sea CO 2 fluxes from the ocean inversion (2000) Gruber et
al. (2009) AIR-SEA FLUXES CONTEMPORARY FLUXES (mol m -2 yr -1 )
ANTHROPOGENIC FLUXES (mol m -2 yr -1 ) NATURAL (PI) FLUXES (mol m
-2 yr -1 ) 2000
Slide 3
3 Gruber et al. (2009) AIR-SEA FLUXES Global uptake of
anthropogenic CO 2 : 2.2 Pg C yr -1 Air-sea CO 2 fluxes from the
ocean inversion
Slide 4
4 Gruber et al. (2009) AIR-SEA FLUXES The importance of lateral
transport
Slide 5
5 Gruber et al. (2009) AIR-SEA FLUXES The importance of lateral
transport storage flux transport storage flux transport
Slide 6
6 How were these air-sea fluxes estimated? Gruber et al. (2009)
Using classical Greens function inverse methods, one can infer the
surface sources and sinks of anthropogenic and natural CO 2 from
their ocean interior distribution. Natural carbon, i.e. C gasex
Anthropogenic carbon AIR-SEA FLUXES
Slide 7
7 Uncertainty estimate provided by range of model results
AIR-SEA FLUXES Estimates come with formal uncertainty estimates,
mostly stemming from the spread of ocean models Gruber et al.
(2009)
Slide 8
8 Air-sea fluxes (and transports) from ocean inversion SUMMARY
contact: [email protected] STRENGTHSLIMITS Independent
data-based estimate (independent of pCO 2 data and gas-exchange
coefficient) Formal uncertainty estimates (including co-variances
and estimates for individual models) Attribution to natural and
anthropogenic fluxes (for 1995, 2000, 2005) Only annual mean fluxes
(no monthly estimates ) Error stems from a combination of data and
ocean transport uncertainties Permits to estimate fluxes, storage,
and lateral transport (for natural, anthropogenic, and contemporary
carbon)
Slide 9
9 Access to the data ACCESS contact: [email protected]
PATH http://lgmacweb.env.uea.ac.uk/lequere/recc CONTENT go to ETH
folder readme_eth.txt fluxes_covariances_OIP_1995-2000-2005.mat
gridded_results_OIP_1995-2000-2005.nc
Slide 10
10 JOINT INVERSION ADD-ON: Joint-atmosphere-ocean inversion
Substantial shift in mean flux for tropical and southern land
regions
Slide 11
11 The End.
Slide 12
12 Convergence of air-sea CO 2 flux estimates Gruber et al.
(2009) AIR-SEA FLUXES A remarkable agreement is found, with the
exception of the regions south of 44S. Annual fluxes (nominal year
of 2000)
Slide 13
13 Comparison of ocean inverse estimates with Takahashi
climatologies Gruber et al. (2009) With the exception of the
Southern Ocean, each subsequent edition of the Takahashi et al.
climatology became more consistent with the results of the ocean
inversion. AIR-SEA FLUXES
Slide 14
14 Comparison of ocean inverse estimates with TransCOM Gruber
et al. (2009) Moving from L1 to L3, TransCOMs estimates became more
consistent with those from the ocean inversion AIR-SEA FLUXES
Slide 15
15 Ocean Inversion Method The ocean is divided into 30 regions
Mikaloff Fletcher et al. (2006, 2007) AIR-SEA FLUXES
Slide 16
16 Basis functions are model simulated footprints of unit
emissions from a number of fixed regions Estimate linear
combination of basis functions that fits observations in a least
squares sense. Inversion is analogous to linear regression
footprints fluxes obs Premultiply both sides by inverse of A
estimated fluxes Inversion of ocean interior observations using a
Greens function approach AIR-SEA FLUXES