1. Inversion of continuous data over Europe : a pseudo-data analysis. C. Carouge and P. Peylin ; P. Bousquet ; P. Ciais ; P. Rayner Laboratoire des Sciences du Climat et de l’Environnement Acknowledgement : all experimentalists from Aerocarb project

2. high spatial resol. model daily time step inversion How to assimilate daily measurements ? Schauinsland CO2 (ppm)

3. Period : 1 year = 2001 Observations : daily modelled concentrations. European NEP fluxes from ORCHIDEE. 10 European stations Inversion setup : Data MHD SAC PUY PRS SCH CBW WES PAL HUN CMN AEROCARB data base : http://www.aerocarb.cnrs-gif.fr/database.html

4. Transport model : LMDZ, zoom over Europe Nudged on ECMWF winds 192 x 146 and 19 vertical levels - 0.5 x 0.5 degrees in the zoom - 4 x 4 degrees at the lowest resolution

5. Fluxes : - Europe & North east Atlantic : each pixel / daily - Elsewhere : subcontinental regions / monthly Prior : Fluxes : Europe : 0 fluxes OR TURC NEP fluxes Elsewhere : 0 fluxes Errors : 1 GtC/year over Europe 0.5 GtC/year over north east Atlantic Correlations : spatial and temporal correlations between European / N.Atlantic pixels Inversion setup : prior information

6. Spatial and temporal correlations « distance » correlations : extent of synoptic events L land/ocean : 1000/1500 km L temporal : 10 days « climate » correlations : structure of synoptic events Monthly correlations between daily NEP fluxes from ORCHIDEE X distance correlations « biome » correlations : structure of vegetation types Linear relation between predominant biomes of ORCHIDEE X distance correlations

7. Distance Illustration of correlations Climate x distance (November) Biomes x distance

8. Technical aspects : Synthesis inversion to get posterior errors : Sequential approach with overlap : 11 * 2 months inversions Still 7000*60 unknowns covariance matrix of ~ 400,000 x 400,000 !! Use “retro-plume approach” (~ adjoint) to get daily response functions for all pixels Huge memory size problems !

9. PSEUDO DATA : Perfect transport

10. Annual error reduction maps : Distance correlations Climate correlations 0102030 percentage

11. 20012001.52001.2520022001.75 2001.2520012001.752001.52002 PRS SAC correlation prior/poste : 0.69 / 0.79 correlation prior/poste : 0.69 / 0.53 Prior (with TURC) posterior ORCHIDEE (Truth) 0 4 8 -4 -6 0 4 gC/m²/day Pixel resolution

12. Mediterranean Europe Western Europe Prior (with TURC) posterior ORCHIDEE (Truth) 20012001.52001.2520022001.75 2001 2001.5 2001.2520022001.75 2 0 1 -3 -2 0 gC/m²/day Regional resolution correlation prior/poste : 0.89 / 0.94 correlation prior/poste : 0.55 / 0.77

13. 0.5 0.1 0.3 2.4 2.8 2.0 1.6 1.4 1.0 0.2 0.4 0.6 0.8 1.8 Normalised standard dev. residual correlation Correlation: prior vs. true Correlation: posterior vs. true NSD prior NSD posterior (NSD true = 1) 1 day 8 days 15 days 1 day8 days 15 days Time smooth length Residual : flux – seasonal flux

14. PSEUDO DATA : Non-perfect transport

15. Western Europe 0 2 -2 2.5 -4 0.6 1.5 0.4 0.2 3.5 Normalised standard dev. residual correlation 20012001.52001.25 2002 2001.75 Flux (gC/m²/day) Correlation posterior Correlation prior NSD prior NSD posterior Prior (with TURC) posterior ORCHIDEE (Truth) 1 day 8 days 15 days Time smooth length

16. Actual data : new setup Observations : daytime averaged Fluxes : - Europe & North east Atlantic : each pixel / daily - Elsewhere : subcontinental regions / monthly Prior : Fluxes : pre-optimised monthly fluxes Errors : 1 GtC/year over Europe 0.5 GtC/year over north east Atlantic tiny on other regions

17. Normalised standard dev. residual correlation 20012001.52001.25 2002 2001.75 Flux (gC/m²/day) Prior (with TURC) ORCHIDEE (Truth) 1 day 8 days 15 days Time smooth length Western Europe posterior 15 10 5 0 -5 0.2 0.1 0 -0.1 0 2 4 6 8 Correlation posterior Correlation prior NSD prior NSD posterior

18. Fit to observations 440 400 360 370 380 20012001.52001.25 2002 2001.75 20012001.52001.25 2002 2001.75 CO 2 (ppm) priorObs. posterior CBW CMN

19. Conclusions … 1 year of pixel inversion is technically possible only W. Europe can be really resolved with current network Transport uncertainties are critical … and Perspectives data selection

20. May November Flux correction : posterior - prior -250 -160 -70 20 110 200 (gC / m 2 / month) First inversion Updated inversion

21. AEROCARB data base : http://www.aerocarb.cnrs-gif.fr/database.html Continuous sites Continuous European measurement sites

22. Technical aspects : Synthesis inversion to get posterior errors : Sequential approach with overlap : 11 * 2 months inversions Still 7000*60 unknowns covariance matrix of ~ 400,000 x 400,000 !! Use “retro-plume approach” (~ adjoint) to get daily response functions for all pixels Huge memory size problems ! Two steps inversion : - 1 st : standard monthly Fluxes + Globalview data - 2 nd : daily fluxes using the 1 st step estimated fluxes..

23. Retro-plume approach : Day 1Day 4 Station Zotino (Russia) October 2001 Longitude Latitude

24. Taylor diagram Residual correlation Total Europe / Western Europe TP: TURC fluxes 1: no correlation 2: prior 0 / distance 3: prior 0 / climate x distance 4/5/6: prior Turc / distance 7: prior Turc / climate x distance 8: prior Turc / climate 300.511.522.5 3 0 0.5 1 1.5 2 2.5 Normalised standard deviation TRUTH