Toward a mesoscale flux inversion in the 2005 CarboEurope Regional Experiment T.Lauvaux, C. Sarrat, F. Chevallier, P. Ciais, M. Uliasz, A. S. Denning, P. Rayner GHG cycle in the Northern Hemisphere, Open Science Conference, Sissi-Lassithi, Crete, November ESA image

Observations + errors Aircrafts towers Sources and Sinks a priori + errors Meteo (meso NH) Model gives Concentration of CO2 Correction by inversion Large scale [CO2] Boundary conditions (LMDZ) Information on error coherence from eddy-flux data Particle Dispersion model Inversion of sources and sinks of CO2

CarboEurope Regional Experiment Network Regional budget of CO2 in the South West of France from ground based observations and aircraft data observation sites: Flux and CO2 concentration Piper Aztec Flux tower Concentration tower

Mesoscale atmospheric modelling MésoNH coupled with ISBA-A-gs: dynamical fields corresponding to wind and turbulence (u, v, w, Tp, TKE, u*, LMO,...) Resolution of 8km in a domain of about 700*700 km2 (South West of France) Coupling with a vegetation scheme ISBA-Ag-s, parameterised with Ecoclimap_v3: Transport of atmospheric CO2 based on ISBA-A-gs fluxes Transport and carbon fluxes from the 23rd to the 27th of May 2005

Lagrangian Particle Dispersion Model Off-line coupling of mesoNH dynamical fields with LPDM: determination of diagnostic physical parameters Trajectories backward in time from the receptors to the sources Particle releasing frequency, number, particle lost (sedimentation,...), time dependant dynamics Integration of instrumented towerd data and aircraft data  4 vertical boundaries (N, S, E, W) with 2 vertical layers (BL, FT)  Surface grid

All particules emitted by grid point i All Particles ‘emitted’ by lateral boundary grid point j Forward mode J i

Those Particules emitted by all surface grid points who reach the detector Those particules ‘emitted’ by all lateral boundary grid points who reach the detector Backward mode

Meteorological context during the 27th of may 27th may - 6pm 27th may – 2am 27th may - 2pm Sarrat et al., 2006 Early growth season for summer crops  Mainly influenced by the boundary conditions?

Particle distribution in time and space Hourly distribution of the particles originating from the lateral boundaries OriginTowerAircraft Surface87%40% High bounds10%55% Low bounds3%5% Limited time window for the inversion Tower concentrations dominated by the surface fluxes  model weakness ?  vertical profile of the variance on a concentration tower hours Aircraft data improve the constrain on the boundary unknowns

Error reduction on 4-day inversion Spatial distribution of the particles: Extension of the influenced zone Biscarosse (20m) Marmande (70m) 2 aircraft flights Biscarosse (200m) Marmande (70m) 2 aircraft flights  Increase of the regional influence at a higher observation site  Limited impact for high altitude flights

Spatial error correlation on the fluxes At this scale, can we extend the information by a spatial correlation in the background covariance error matrix ? Maize – Maize (short distance) R 2 = 0.9Maize – Maize (long distance) R 2 = 0.1Pine forest – Bare soil (short distance) R 2 = 0.5Maize – Maize + Bean R 2 = 0.1

Conclusions Complete inversion system at the meso-scale Ready for real data… ESA image