1. Peter Cox (Met Office) Martin Heimann, Wolfgang Knorr (MPI-BGC) Tony Hollingsworth, Richard Engelen (ECMWF) Philippe Ciais, Philippe Peylin (LSCE) Alain Chedin (LMD) GEMS – GREENHOUSE GASES Objectives Heritage and Partner Projects Deliverables Workpackages

2. 1.To monitor daily-to-seasonal variations in 3d fields of atmospheric CO 2. 2.To provide improved estimates of CO 2 sources and sinks. 3.To diagnose the relative contributions to land carbon sources and sinks. 4.To monitor daily-to-seasonal variations in CH 4, N 2 O, CO. GEMS-GHG Objectives

3. GEMS-GHG Heritage and Partner Projects COCO FP5 Project (Dec 2001 – Dec 2004) [obj. 1] CarboEurope (FP5 cluster and FP6 IP) CarboEurope - AEROCARB (March 2000 – March 2003) [obj. 2,3] CarboEurope - CAMELS (Nov 2002 – Nov 2005) [obj. 3] EVERGREEN (non-CO 2 retrievals) (2002-2005) [obj. 4] MERSEA (includes Ocean GEMS) FP6 IP GEOLAND (includes Land GEMS) FP6 IP

4. GEMS-GHG Deliverables Year 1: Maps of column integral CO 2, 120km, 10-day mean Year 2: 4d fields of CO 2, quality controlled against in situ measurements (120km,10-day mean) Year 2: Maps of column integral CH 4, N 2 O, CO (daily?), 120km, 10-day mean Year 3: CO 2 sources and sinks (10-day mean, 120km) validated against bottom-up flux estimates (e.g. CARBOEUROPE) Year 4: Retrieval of process model parameters and attribution of CO 2 sources and sinks.

5. 1.4d retrieval of CO 2 from remote sensing. [Engelen, ECMWF] 2.Assessment of CO 2 retrievals [Heimann, MPI-BGC] 3.Inversions to estimate CO 2 sources and sinks [Ciais, LSCE] 4.Development of a CCDAS to estimate contributions to land CO 2 sources and sinks. [Cox, UKMO] 5.Prototype system to retrieve column integral CH 4, N 2 O, CO. [Chedin, LMD] GEMS-GHG Workpackages

6. 1.Are the subproject deliverables realistic given the time and resource constraints? (e.g. should we focus just on CO 2 ?) 2.Does the consortium have sufficient expertise in all of the relevant areas? Do we need additional groups for the forward modelling of non-CO 2 GHGs? 3.How will we deal with ocean-atmosphere fluxes? Links to MERSEA? 4.Can we find a way to unify the two approaches to modelling CO 2 sources and sinks? 5.How should we subdivide GEMS GHG, and who will lead the writing of each part? (...keep your heads down!) GEMS-GHG Outstanding Issues

7. WP1: 4d retrieval of CO 2 from remote sensing ( WP leader: Richard Engelen, ECMWF)