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Transcript of Page 1© Crown copyright WP4 Development of a System for Carbon Cycle Data Assimilation Richard...
© Crown copyright Page 1
WP4 Development of a System for Carbon Cycle Data Assimilation
Richard Betts
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Contents
The presentation covers the following sections
Objectives
Work description
Inputs
Milestones
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WP4 Objectives
“To assemble all information on land-biosphere processes provided by WPs 1 and 3 into a common framework, to ultimately enable carbon source and sink estimates at global terrestrial surfaces at a spatial resolution that satisfies the requirement of a carbon reporting system in support of the Kyoto Protocol.”
To develop a prototype carbon cycle data assimilation system (CCDAS), making use of the best carbon models and data.
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WP4 Work description
develop inverse models for the TEMS and the atmospheric transport model (ATM)
use these within an offline Carbon Cycle Data Assimilation System (CCDAS), to adjust TEM parameters and prior flux estimates based on a 20-25 year simulation period.
Implement in an AGCM, using existing Numerical Weather Prediction (NWP) data assimilation system where possible to nudge internal model variables (e.g. respiring carbon) to optimally fit the observations.
Carry-out a prototype online CCDAS experiment to infer the European carbon balance from1990 onwards.
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WP4 Inputs
Atmospheric CO2 data and remotely-sensed biophysical parameters (WP1)
Improved TEMs and parameters based on model validation(WP2)
Initial carbon stores and model parameters based on 20th century land carbon balance (WP3).
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WP4 Milestones
Month 15: Met data available to drive TEMs
Month18: Offline simulations of European carbon balance (20-25 years)
Month 21: Comparison of forward and inverse estimates
Month 24: Inverse TEMS ready
Month 27: Offline CCDAS tests completed
Month 30: Report on design of offline and online nowcasting systems
Month 36: Report on contemporary European land carbon sink.
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Framework for CCDAS
Dual observation and modelling approach, based inversion of atmospheric observations and on the use of satellite data and ecosystem models.
Bottom up integration using MOSES/JULES and Spatial Data
Top down Methods based on the Inversion of Atmospheric Concentrations
Dual observation and modelling approach, based inversion of atmospheric observations and on the use of satellite data and ecosystem models
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Forward Modelling
Method : Build “bottom-up” process-based models of land and ocean
carbon uptake.
Advantages : a) Include physical and ecophysiological constraints; b) Can
isolate land-management effects; c) can be used predictively (not just
monitoring).
Disadvantages : a) Uncertain (gaps in process understanding); b) Do not
make optimal use of large-scale observational constraints.
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Forward Modelling – Using JULES/TRIFFID
TEM (MOSES/TRIFFID)
Satellite data(=1-10d)
Land cover
Leaf area indexLeaf typeBiomass and changes
Canopy structure
Radiation/FAPAR
Ecosystem data(=1-10yr)
Soil data(t>10yr)
Disturbance
Land Use history ( HYDE dataset)
Biomass
Texture
Drainage classes
TopographyMet data(t>1d)
TemperaturePrecipitationRadiationVapour PressureHumidityWet daysSnow
•Soil H2O•C uptake•C release
NPP
NEP
NBP
(=1d-1yr)
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Inverse Modelling
Method : Use atmospheric transport model to infer CO2 sources and
sinks most consistent with atmospheric CO2 measurements.
Advantages : a) Large-scale; b) Data based (transparency).
Disadvantages : a) Uncertain (network too sparse); b) not constrained
by ecophysiological understanding; c) net CO2 flux only (cannot isolate
land management).
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Inverse Modelling
Flask air sample networks Flux networks ( carboeurope)
Others (air crafts)
Atmospheric tracer and inversion methods
C Sources, sinks(=1-10yr)
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Inverse Modelling - Uncertainties
Fan et al. (1998): 1.7 GtC/yr sink in North America.
Bousquet et al. (1999): 0.5 +/- 0.6 GtC/yr in North America, 1.3 GtC/yr in
Siberia.
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Dual Constraint Approach
Atmospheric observations Atmospheric tracer models
Global – regionalC sources,sinks
CCDAS – Carbon Monitoring system
Ecosystem observations Ecosystem Models (MOSES/TRIFFID)
Regional – localC sources,sinks
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Conclusions
The Kyoto Protocol (and any subsequent agreements designed to curb
global warming) will require monitoring of carbon emissions and uptake.
Modelling and measurement techniques have been developed which can
estimate land-atmosphere exchange (i.e. Kyoto sinks) at various time and
space scales.
A carbon data assimilation system is required to optimally combine these
approaches and to make best use of future CO2 measurements from satellite.
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