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 Atmospheric chemistry modelling at LSCE First results of PYVAR system Update on “traditional” inversions

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

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

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

HYMN, 1st annual meeting, Totnes October 22-24, 2007 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 What is PYVAR ?

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

HYMN, 1st annual meeting, Totnes October 22-24, 2007 Inversion at model resolution (96x72) Weekly time resolution (48 steps per year) CH 4, CO, CH 2 O, H 2, 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 PYVAR inversion

HYMN, 1st annual meeting, Totnes October 22-24, 2007 SACAS : Comparison with INCA CH 2 O CH 4 CO H2H2 MCF

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

HYMN, 1st annual meeting, Totnes October 22-24, 2007 SACAS : Atmospheric biases CH 4 CO ppm

HYMN, 1st annual meeting, Totnes October 22-24, 2007 SACAS : Atmospheric biases MCF H2H2 ppm

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

HYMN, 1st annual meeting, Totnes October 22-24, 2007 SACAS : First annual increments CH 4 CO xkg/m 2 /s

Large TRANSCOM regions Several processes on each period MCF optimisation to get OH CH 4 optimisation using optimized OH over Monthly emissions & observations. Use of 13 CH4 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 Update on “Traditional” inversion

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

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

HYMN, 1st annual meeting, Totnes October 22-24, 2007 Update on methane inversion Inversion with 13 CH 4 data Inversion without 13 CH 4 data Impact of isotopic observations Biomass burning CH 4 emissions

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

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

HYMN, 1st annual meeting, Totnes October 22-24, 2007 WP5 : Forward simulations with full LMDZ-INCA model - Outputs for year 2004 given to HYMN - Optimized CH 4 emissions available ( ) WP6 : Inverse modelling - Multi-species variational system ready - Traditional inversion for CH 4 and H 2 ready N 2 O observations ? Available through NitroEurope IP (NOAA, AGAGE, RAMCES, other ?) Work in progress …

HYMN, 1st annual meeting, Totnes October 22-24, 2007 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 CH 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.

Objectives Estimate the surface emissions of CH4 and H2 on a regional basis base on inverse modelling and their evolution over the period Estimate the evolution of global and hemispheric OH in the atmosphere over the period 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. WP6

HYMN, 1st annual meeting, Totnes October 22-24, 2007 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 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 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 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 Inversion setup (to be discussed) : 1-year inversion for 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 ? WP6 : Planned work for HYMN

HYMN, 1st annual meeting, Totnes October 22-24, 2007 CH4 budget with KNMI & LSCE variational systems H2 budget with LSCE variational system (if available) Use of traditional inversions for CH4 ( ) & H2 ( ) 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 WP6 : Planned work for HYMN

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

3/ 2030 simulation HYMN, 1st annual meeting, Totnes October 22-24, 2007 Atmospheric chemistry modelling at LSCE LMDz-INCA General Circulation Model. INCA: tropospheric gaz phase chemistry, aerosols and long- lived greenhouse gases (CO 2, CH 4, N 2 O). 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. 1/ Global to regional scale modeling platform 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. 2/ long-term simulation RETRO EU project ( ) : 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.

3 day (NCEP) and 5 day (ECMWF) forecasts for global tropospheric chemistry, aerosols and long-lived greenhouse gases (CO 2, CH 4, N 2 O) 1/ LMDz-INCA global chemical weather platform HYMN, 1st annual meeting, Totnes October 22-24, 2007

Bousquet et al., 2005, 2006 MCF/CH 4 inversion Emissions Prior Poste OH Prior Poste MCF inversion (CH 3 CCl 3 ) Methane Inversion

HYMN, 1st annual meeting, Totnes October 22-24, 2007 Hauglustaine et al., JGR, 2004 Standard horizontal res  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 The general circulation model: LMDz-INCA

HYMN, 1st annual meeting, Totnes October 22-24, 2007 SACAS : First annual increments MCF H2H xkg/m 2 /s