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Attributing direct radiative forcing to specific emissions using adjoint sensitivities

Attributing direct radiative forcing to specific emissions using adjoint sensitivities. Daven K Henze, Drew T. Shindell , Robert J. D. Spurr. g -con. Radiative Forcing Transfer Functions. How to calculate the radiative forcing change for a given change in emissions?. IPCC, 2007.

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Attributing direct radiative forcing to specific emissions using adjoint sensitivities

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  1. Attributing direct radiative forcing to specific emissions using adjoint sensitivities Daven K Henze, Drew T. Shindell, Robert J. D. Spurr g-con

  2. Radiative Forcing Transfer Functions How to calculate the radiativeforcing change for a given change in emissions? IPCC, 2007 Global contributions to aerosol direct RF

  3. Radiative Forcing Transfer Functions How to calculate the radiative forcing change for a given change in emissions? Using transfer function T:

  4. Radiative Forcing Transfer Functions How to calculate the radiative forcing change for a given change in emissions? Using transfer function T: Approximate Tusing adjoint: Calculated using GC adjoint(Henze et al., 2007 and LIDORT (Spurr, 2002)

  5. Radiative Forcing Transfer Functions The % change in radiative forcing per change in BC emission: note: per change in any BC emission. This shows variation in efficiency of BC emissions forcing.

  6. Radiative Forcing Transfer Functions The % change in radiative forcing per change in SO2 emission:

  7. Applying to MFR 2030 – 2000 inventories BC, Total SO2, Total

  8. Applying to MFR 2030 – 2000 inventories BC, Total SO2, Total

  9. Applying toCLE 2030 – 2000 inventories BC, Total SO2, Total

  10. Applying toCLE 2030 – 2000 inventories BC, RESALL SO2, RESALL

  11. Applying toCLE 2030 – 2000 inventories BC, POWER SO2, POWER

  12. Validation: BC CLE 2030 – 2000 perturbation Looks good

  13. Validation: SO2 CLE 2030 – 2000 perturbation Looks OK, but adjoint-approach biased?

  14. Validation: SO2 Check: does reducing perturbation reduce nonlinearity? CLE 2030 – 2000 perturbation 10% perturbations Yes. The adjoint code is accurate.

  15. Validation: SO2 ESO2 E’’2030 E2000 E’2030 RF |ADJ| <|FD| |ADJ| >|FD| Can we anticipate bias?

  16. Validation: SO2 Yes, bias can be anticipated. Also, overall ordering remains the same. E2030 < E2000 (Europe ) E2030 > E2000 (China, India) CLE 2030 – 2000 perturbation Conclusion: adjoint sensitivities provide a rapid means of exploring the effect of specific emissions changes on aerosol DRF.

  17. The end Thanks to: Columbia Univ. Earth Institute Fellowship Drew Shindell, Rob Spurr, Nadine Unger, John Seinfeld NASA GSFC: NCCS NASA JPL: SCC

  18. Radiative Forcing with GEOS-Chem Forward model Sensitivity calculation: GEOS-Chem GC Adj Henze et al., 2007 [SIA], [BC], RH, Ddry Mie Code derivate mode Mie Code Grainger et al., 2004 Following Martin et al., 2004, Drury et al., 2008 Radiative Transfer Code Radiative Transfer Code LIDORT (Spurr, 2002) Weighting functions TOA upward SW flux

  19. Radiative Forcing with GEOS-Chem GEOS-Chem [SIA], RH Literature Ddry N, Dwet Mie Code Grainger et al., 2004 (tabulate as )

  20. Validating Radiative Forcing Sensitivity Phase function coefficients for SIA(Dwet) Dmax ignore Dmin

  21. Validating Radiative Forcing Sensitivity Mie results for extinction at discrete mode diameters:

  22. Radiative Forcing (forward calculation) Chemical Transport Model Aerosol concentrations Mie Code optical properties

  23. Radiative Forcing Sensitivity GEOS-Chem Adj Henze et al., 2007 LIDORT Spurr, 2002 Jacobian calculation [SIA]*, [BC]* Mie Derivative Grainger et al., 2004

  24. Radiative Forcing (forward calculation) Chemical Transport Model Radiative Transfer Code Aerosol concentrations TOA upward SW fluxes Mie Code optical properties

  25. Next Steps • Validate the transfer functions • Apply to various emissions perturbations of interest

  26. Radiative Forcing Sensitivity 1 week 24 hr Radiative Transfer Code LIDORT (Spurr 2002) Jacobian calculation GEOS-Chem Adj [SIA]*, [BC]* Mie Derivative

  27. Radiative Forcing with GEOS-Chem GEOS-Chem Radiative Transfer Code [BC] LIDORT (Spurr, 2002) [SIA], RH Ddry TOA upward SW flux N, Dwet Mie Code Grainger et al., 2004 Following Martin et al., 2004; Drury et al,. 2008 (external mixture)

  28. Radiative Forcing with GEOS-Chem Forward model Sensitivity calculation GEOS-Chem GEOS-Chem Adj 1 wk Henze et al., 2007 [SIA], [BC], RH, Ddry [SIA]*, [BC]* Mie Code Grainger et al., 2004 Mie Code derivate mode Radiative Transfer Code Radiative Transfer Code LIDORT (Spurr, 2002) Following Martin et al., 2004, Drury et al., 2008 Weighting functions TOA upward SW flux 24 hr

  29. Applying to CLE 2030 inventories note: this takes about 10 seconds

  30. Applying to MFR 2030 inventories

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