1. Page 1© Crown copyright WP4 Development of a System for Carbon Cycle Data Assimilation Richard Betts

2. Page 2© Crown copyright Contents The presentation covers the following sections  Objectives  Work description  Inputs  Milestones

3. Page 3© Crown copyright 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.

4. Page 4© Crown copyright 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.

5. Page 5© Crown copyright 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).

6. Page 6© Crown copyright 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.

7. Page 7© Crown copyright 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

8. Page 8© Crown copyright 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.

9. Page 9© Crown copyright Forward Modelling – Using JULES/TRIFFID TEM (MOSES/ TRIFFID) Satellite data (  =1-10d) Land cover Leaf area index Leaf type Biomass and changes Canopy structure Radiation/FAPAR Ecosystem data (  =1-10yr) Soil data (  t>10yr) Disturbance Land Use history ( HYDE dataset) Biomass Texture Drainage classes Topography Met data (  t>1d) Temperature Precipitation Radiation Vapour Pressure Humidity Wet days Snow Soil H2O C uptake C release NPP NEP NBP (  =1d-1yr)

10. Page 10© Crown copyright Inverse Modelling Method : Use atmospheric transport model to infer CO 2 sources and sinks most consistent with atmospheric CO 2 measurements. Advantages : a) Large-scale; b) Data based (transparency). Disadvantages : a) Uncertain (network too sparse); b) not constrained by ecophysiological understanding; c) net CO 2 flux only (cannot isolate land management).

11. Page 11© Crown copyright Inverse Modelling Flask air sample networks Flux networks ( carboeurope) Others (air crafts) Atmospheric tracer and inversion methods C Sources, sinks (  =1-10yr)

12. Page 12© Crown copyright 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.

13. Page 13© Crown copyright Dual Constraint Approach Atmospheric observations Atmospheric tracer models Global – regional C sources,sinks CCDAS – Carbon Monitoring system Ecosystem observations Ecosystem Models (MOSES/TRIFFID) Regional – local C sources,sinks

14. Page 14© Crown copyright 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 CO 2 measurements from satellite.

15. Page 15© Crown copyright