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 14-18

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Observations+ errorsAircraftstowers

Sources and Sinksa priori+ errors

Meteo(meso NH)

Model givesConcentration of CO2

Correctionby inversion

Large scale [CO2]Boundary conditions (LMDZ)

Information on errorcoherence fromeddy-flux data

ParticleDispersionmodel

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 AztecFlux towerConcentration 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

0

5

10

15

20

25

30

35

40

45

50

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38

Hourly distribution of the particlesHourly distribution of the particles originating from the lateral boundaries

Origin Tower Aircraft

Surface 87% 40%

High bounds 10% 55%

Low bounds 3% 5%

Limited time window for the inversion

Tower concentrations dominatedby the surface fluxes

model weakness ? vertical profile of the variance on a concentration tower

1 12 24 36 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

0 0.5 1

Spatial error correlation on the fluxes

AURADE - LAMASQUEREcereals - cereals R2 = 0,9059

-30

-20

-10

0

10

20

30

40

-15 -10 -5 0 5 10 15 20 25 30

LEBRAY - BILOSforest - hard ground R2 = 0,5621

-7

-6

-5

-4

-3

-2

-1

0

1

2

3

4

-25 -20 -15 -10 -5 0 5 10 15 20

MARMANDE - LA CAPE SUDmaize - maize+beans

R2 = 0,1192

-5

-4

-3

-2

-1

0

1

2

3

4

5

6

-5 -4 -3 -2 -1 0 1 2 3

SAINT SARDOS - MARMANDEmaize - maize R2 = 0,1244

-5

-4

-3

-2

-1

0

1

2

3

4

5

-8 -6 -4 -2 0 2 4 6

At this scale, can we extendthe information by a spatial correlation in the background covariance error matrix ?

Maize – Maize (short distance) R2 = 0.9Maize – Maize (long distance) R2 = 0.1Pine forest – Bare soil (short distance) R2 = 0.5Maize – Maize + Bean R2 = 0.1

Conclusions

Complete inversion system at the meso-scale

Ready for real data…

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