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Adjoint TM5

Adjoint TM5. Maarten Krol Peter Bergamaschi, Jan Fokke Meierink, Henk Eskes, Sander Houweling. Why an Adjoint TM5?. Concentrations on a station depend on emissions Interesting quantity: dM(x,t)/dE(I,J,t’)

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Adjoint TM5

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  1. Adjoint TM5 Maarten Krol Peter Bergamaschi, Jan Fokke Meierink, Henk Eskes, Sander Houweling

  2. Why an Adjoint TM5? • Concentrations on a station depend on emissions • Interesting quantity: dM(x,t)/dE(I,J,t’) • How does a ‘station’ concentration at t changes as a function of emissions in gridbox (I,J) at time t’? • Inverse problem: from measurements M (t) --> E(I,J,t’)

  3. Adjoint • dM(t)/dE(I,J) (constant emissions) can be calculated with the adjoint in one simulation • M0 = f(E0(I,J)) • M(t) = M0 + dM(t)/dE(I,J)*(E(I,J)-E0(I,J)) • Only if the system is linear! • Example: MCF at Finokalia

  4. Finokalia MINOS 2001 measurements Dirty Clean

  5. Finokalia • Integrations from M(t) back to july, 15. • Forcing at station rm(I,J,1) = rm(I,J,1) + forcing (at averaging period t, t+dt) • Adjoint chemistry • Adjoint emissions give dM(t)/dE(I,J)

  6. Clean

  7. Dirty

  8. Clean

  9. Dirty

  10. Clean

  11. Dirty

  12. Clean

  13. Dirty

  14. Prior MCF emission distribution

  15. Procedure • Minimise • With

  16. Negatives Emissions over sea Posterior MCF emissions:

  17. penalty if over sea

  18. apri=pland

  19. Conclusions • Results sensitive to prior information • Not surprising: 8 observations <==> 1300 unknowns • Emissions required: 10-30 gG/year • How to avoid negatives?

  20. Next Steps (to be done) • Prior Information • non-negative • full covariance matrix • Full 4Dvar, starting with obtained solution as starting guess emissions • Influence station sampling, BL scheme, …. • Faster calculations (parallel version?)

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