Adjoint TM5 Maarten Krol Peter Bergamaschi, Jan Fokke Meierink, Henk Eskes, Sander Houweling
Jan 11, 2016
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’)– 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’)
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
Finokalia MINOS 2001 measurements
Dirty
Clean
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)
Clean
Dirty
Clean
Dirty
Clean
Dirty
Clean
Dirty
Prior MCF emission distribution
Procedure
• Minimise
• With
Posterior MCF emissions:
Negatives
Emissions over sea
penalty if over sea
apri=pland
Conclusions
• Results sensitive to prior information
• Not surprising: 8 observations <==> 1300 unknowns
• Emissions required: 10-30 gG/year
• How to avoid negatives?
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?)