© Crown copyright Page 1

WP4 Development of a System for Carbon Cycle Data Assimilation

Richard Betts

© Crown copyright Page 2

Contents

The presentation covers the following sections

Objectives

Work description

Inputs

Milestones

© Crown copyright Page 3

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.

© Crown copyright Page 4

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.

© Crown copyright Page 5

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).

© Crown copyright Page 6

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.

© Crown copyright Page 7

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

© Crown copyright Page 8

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.

© Crown copyright Page 9

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)

© Crown copyright Page 10

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).

© Crown copyright Page 11

Inverse Modelling

Flask air sample networks Flux networks ( carboeurope)

Others (air crafts)

Atmospheric tracer and inversion methods

C Sources, sinks(=1-10yr)

© Crown copyright Page 12

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.

© Crown copyright Page 13

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

© Crown copyright Page 14

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.

© Crown copyright Page 15