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Towards a multi-species variational assimilation system for surface emissions of CH 4 , CO, H 2

Towards a multi-species variational assimilation system for surface emissions of CH 4 , CO, H 2. I. Pison, F. Chevallier, and P. Bousquet Laboratoire des Sciences du Climat et de l’Environnement (LSCE). HYMN, 1st annual meeting, Totnes October 22-24, 2007. Outline.

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Towards a multi-species variational assimilation system for surface emissions of CH 4 , CO, H 2

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  1. Towards a multi-species variational assimilation system for surface emissions of CH4, CO, H2 I. Pison, F. Chevallier, and P. Bousquet Laboratoire des Sciences du Climat et de l’Environnement (LSCE) HYMN, 1st annual meeting, Totnes October 22-24, 2007

  2. Outline • Atmospheric chemistry modelling at LSCE • First results of PYVAR system • Update on “traditional” inversions HYMN, 1st annual meeting, Totnes October 22-24, 2007

  3. Atmospheric chemistry modelling at LSCE Forward modelling Inverse modelling LMDZ-INCA Full model LMDZ-INCA GHG SACAS Simplified Atm. Chemistry Assim. System CHIMERE Regional model Traditional inversion Variational Inversion PYVAR HYMN, 1st annual meeting, Totnes October 22-24, 2007

  4. Inverse method Critical choice of R & B HYMN, 1st annual meeting, Totnes October 22-24, 2007

  5. What is PYVAR ? J cost function HYMN, 1st annual meeting, Totnes October 22-24, 2007

  6. What is PYVAR ? Modular System to combine atmospheric observations and prior information to infer surface fluxes : • LMDZ transport model inside, air mass fluxes nudged on ECMWF winds (u,v) • Variational principle (based on 4D-VAR) • Written in PYTHON language • 1 year of multi-species inversion ~10 days of calculations on an OPTERON PC (5 iterations) • Parallel version in development HYMN, 1st annual meeting, Totnes October 22-24, 2007

  7. Simplified atmospheric chemistry assimilation system Satellite Satellite Satellite SACAS HYMN, 1st annual meeting, Totnes October 22-24, 2007

  8. PYVAR inversion • Inversion at model resolution (96x72) • Weekly time resolution (48 steps per year) • CH4, CO, CH2O, H2, MCF fluxes in the control vector • OH scaling factor for 4 regions in the control vector • Spatial correlation based on correl. length (500 km over lands) • 1-year inversion (2004) performed so far • MCF emissions prescribed with tiny error bars to get OH • Cost function minimized by gradient conjugate (~5 iterations) • Posterior var.-covar. matrix possible with more iterations HYMN, 1st annual meeting, Totnes October 22-24, 2007

  9. SACAS : Comparison with INCA CH2O CO CH4 H2 MCF HYMN, 1st annual meeting, Totnes October 22-24, 2007

  10. SACAS : Improvements of CO simulation Validation of SACAS against MOPITT retrievals > 0 0 < 0 ABS(PRIOR-MOPITT) - ABS(OPT-MOPITT) HYMN, 1st annual meeting, Totnes October 22-24, 2007

  11. SACAS : Atmospheric biases CH4 CO ppm ppm HYMN, 1st annual meeting, Totnes October 22-24, 2007

  12. SACAS : Atmospheric biases MCF H2 ppm ppm HYMN, 1st annual meeting, Totnes October 22-24, 2007

  13. SACAS : Atmospheric biases HYMN, 1st annual meeting, Totnes October 22-24, 2007

  14. SACAS : First annual increments CH4 CO 1010xkg/m2/s HYMN, 1st annual meeting, Totnes October 22-24, 2007

  15. Update on “Traditional” inversion • Large TRANSCOM regions • Several processes on each • 1979-2006 period • MCF optimisation to get OH • CH4 optimisation using optimized OH over 1984-2006 • Monthly emissions & observations. Use of 13CH4 observations • Iterative procedure to calculate response functions • 18 different inversions varying set-up ----> Can provide initial conditions for HYMN HYMN, 1st annual meeting, Totnes October 22-24, 2007

  16. OH variability ? Consistent with top-down estimates ? Bousquet et al., ACP, 2005 HYMN, 1st annual meeting, Totnes October 22-24, 2007

  17. Update on methane inversion NATURAL Decreasing natural emissions v.s. Increasing Anthropic emissions Anomalous deseasonalized flux (TgCH4/yr) ANTHROPIC HYMN, 1st annual meeting, Totnes October 22-24, 2007

  18. Update on methane inversion Impact of isotopic observations Inversion with 13CH4 data Biomass burning CH4 emissions Inversion without 13CH4 data HYMN, 1st annual meeting, Totnes October 22-24, 2007

  19. Update on methane inversion Geographical Europe Source Breakdown Anomalous deseasonalized flux (TgCH4/yr) HYMN, 1st annual meeting, Totnes October 22-24, 2007

  20. First H2 inversions Global Interannual variations 1991 2003 Budget (1990-2003 average) Deposition 1991 2003 Biomass burning 1991 2003 HYMN, 1st annual meeting, Totnes October 22-24, 2007

  21. Work in progress … WP5 : Forward simulations with full LMDZ-INCA model - Outputs for year 2004 given to HYMN - Optimized CH4 emissions available (1985-2006) WP6 : Inverse modelling - Multi-species variational system ready - Traditional inversion for CH4 and H2 ready N2O observations ? Available through NitroEurope IP (NOAA, AGAGE, RAMCES, other ?) HYMN, 1st annual meeting, Totnes October 22-24, 2007

  22. HYMN WP6 Description of work Global chemistry-transport models will be used in conjunction with satellite and ground based observations to improve the estimates in sources and sinks of atmospheric CH4, H2, and N2O. 1. Global forward modelling of CH4, N2O, and H2 and systematic evaluation against satellite data (CH4) and ground based measurements (CH4, N2O, H2). Derive error estimates and biases in model results. 2.1 Inverse modelling of surface emissions and sink by OH oxidation of CH4. 2.2 Inverse modelling of surface emissions, atmospheric photochemical production, destruction by OH and surface uptake of H2. This work will be done based on available surface measurements and satellite observations of CH4. These inversions will be performed on a regional basis. 3. Derive global distributions of optimized sources and sinks of CH4 and H2 through variational assimilation of methane satellite data and surface measurements. HYMN, 1st annual meeting, Totnes October 22-24, 2007

  23. WP6 Objectives Estimate the surface emissions of CH4 and H2 on a regional basis base on inverse modelling and their evolution over the period 1980-2000. Estimate the evolution of global and hemispheric OH in the atmosphere over the period 1980-2000 through inverse modelling. Derive the global optimized distributions of CH4 and H2 sources and sinks on a pixel by pixel basis based on 4D variational data assimilation.

  24. WP6 Deliverables D6.1 Report on model performances in terms of forward simulations of CH4, H2, and N2O using a-priori distribution of emissions and atmospheric sinks and derived error and biases against model results and observations (month 27, coordinated by partner 5). D6.2 Report on emissions of CH4 and H2 over the 1980-2000 period derived from inverse modeling of available satellite and ground-based observations on a regional basis. Comparison with a priori emissions (month 36, partner 5). D6.3 Report on fully optimized distributions of emissions, production, and sinks for CH4 and H2 obtained through 4D var data assimilation (month 36, partner 1). Milestones and expected results M6.1 Forward simulations of H2, CH4, and N2O using a priori emissions and comparison with available observations (planned month 12, finished H2, CH4 simulation, N2O simulation delayed to month 18) M6.2 Inversion of CH4 surface emissions and atmospheric OH over the 1980-2000 period and comparison with a priori emissions (month 33). M6.3 Inversion of H2 surface emission and soil uptake and photochemical production over the period 1980-2000 period (month 33). M6.4 Fully optimized distribution of sources and sinks of CH4 and H2 through variational data assimilation (month 35) HYMN, 1st annual meeting, Totnes October 22-24, 2007

  25. WP6 : Planned work for HYMN Inversion setup (to be discussed) : 1-year inversion for 2004. More ? Time resolution ? Common observations : satellite + surface network + FTIR (keep for validation ?) + aircraft obs (keep for validation ?) + satellite over oceans (validation ?) Common variance scenarios (obs) Aggregated flux or partition between processes ? What about flux prior variances ? Error Correlations for fluxes ? Retrievals ? HYMN, 1st annual meeting, Totnes October 22-24, 2007

  26. WP6 : Planned work for HYMN CH4 budget with KNMI & LSCE variational systems H2 budget with LSCE variational system (if available) Use of traditional inversions for CH4 (1985-2006) & H2 (1990-2006) Test on OH Sensitivity inversions (variational) : - different datasets (satellite, surface) obs freq. - different prior patterns - different OH (from WP5) - others ? Error correl tests Strategy for surface elevation in SCIA. vs models Outputs - to be standardized Plotting package (IDL) available at LSCE for flux comparison WEB interface HYMN, 1st annual meeting, Totnes October 22-24, 2007

  27. Time schedule • Protocol by December • Inverse setup • Surface stations obs. • SCIA treatment • First results May 08 ?

  28. Atmospheric chemistry modelling at LSCE 2/ 1960-2000 long-term simulation 1/ Global to regional scale modeling platform LMDz-INCA General Circulation Model. INCA: tropospheric gaz phase chemistry, aerosols and long-lived greenhouse gases (CO2, CH4, N2O). 3.75° x 2.5°. ORCHIDEE dynamical vegetation model used to derive surface properties, vegetation distribution, carbon cycle, biogenic and soil emissions. 40km x 40km. Real-time chemical weather based on operational meteorology OR reanalysis (ERA40) OR free running GCM. Chimère regional air quality model nested in LMDz-INCA global model. 50km X 50km. 3/ 2030 simulation PHOTOCOMP intercomparison (IPCC AR4-ACCENT) of future atmospheric composition. 25 state-of-the-art global chemistry transport models. 3 different scenarios for future surface emissions. Regional model Chimère constrained by LMDz-INCA : relative impact of emissions versus long-range transport of pollution on air quality in Europe. RETRO EU project (2003-2006) : reanalysis of the tropospheric chemical composition over the past 40 years. Best available meteorology (ERA40), new monthly resolved anthropogenic and biomass burning surface emissions, stratospheric ozone climatologies. Multimodel approach: 2 GCMs with chemistry and 3 CTMs. HYMN, 1st annual meeting, Totnes October 22-24, 2007

  29. 1/ LMDz-INCA global chemical weather platform 3 day (NCEP) and 5 day (ECMWF) forecasts for global tropospheric chemistry, aerosols and long-lived greenhouse gases (CO2, CH4, N2O) http://www.lsce-inca.cea.fr/ HYMN, 1st annual meeting, Totnes October 22-24, 2007

  30. MCF/CH4 inversion Bousquet et al., 2005, 2006 HYMN, 1st annual meeting, Totnes October 22-24, 2007

  31. The general circulation model: LMDz-INCA • Standard horizontal res. 3.75x2.5 • Standard vertical resolution: 19 hybrid -p levels (surface to 35 km). • Dynamic: large scale advection of tracers: LMD climate model • Chemistry: standard version for tropospheric ozone calculation including NMHCs (90 species – 300 reactions); aerosols (mineral, sea-salt, BC, OC, sulfur) : INCA • Biogenic Emissions from the ORCHIDEE dynamical vegetation model • Anthropogenic emissions from either Edgar/IIASA/RETRO • Biomass burning from van der Werf 2006 Hauglustaine et al., JGR, 2004 HYMN, 1st annual meeting, Totnes October 22-24, 2007

  32. SACAS : First annual increments MCF H2 1010xkg/m2/s HYMN, 1st annual meeting, Totnes October 22-24, 2007

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