adjoint tm5

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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’) - PowerPoint PPT Presentation

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  • Adjoint TM5Maarten KrolPeter Bergamaschi, Jan Fokke Meierink, Henk Eskes, Sander Houweling

  • Why an Adjoint TM5?Concentrations on a station depend on emissionsInteresting 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)

  • AdjointdM(t)/dE(I,J) (constant emissions) can be calculated with the adjoint in one simulationM0 = 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

  • Finokalia MINOS 2001 measurements

  • FinokaliaIntegrations 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 chemistryAdjoint emissions give dM(t)/dE(I,J)

  • Clean

  • Dirty

  • Clean

  • Dirty

  • Clean

  • Dirty

  • Clean

  • Dirty

  • Prior MCF emission distribution

  • ProcedureMinimise

    With

  • Posterior MCF emissions:

  • penalty if over sea

  • apri=pland

  • ConclusionsResults sensitive to prior informationNot surprising: 8 observations 1300 unknownsEmissions required: 10-30 gG/yearHow to avoid negatives?

  • Next Steps (to be done)Prior Informationnon-negativefull covariance matrixFull 4Dvar, starting with obtained solution as starting guess emissionsInfluence station sampling, BL scheme, .Faster calculations (parallel version?)

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