1. Recent activities on aerosols in TM5 Achim Strunk Twan van Noije, Michiel van Weele AeroCom-2 contribution by KNMI Preliminary source sink analysis Online dust module EC-Earth/TM5 decadal runs

2. TM-Meeting Wageningen 2011-11-29 AeroCom-2: Overview Aerosol Comparisons between Observations and Models “The AEROCOM-project is an open international initiative of scientists interested in the advancement of the understanding of the global aerosol and its impact on climate.” AeroCom-1: accomplished before IPCC-AR4 AeroCom-2: Ongoing, next stimulus is IPCC-AR5; contribution by many groups/models (CAM*, ECHAM*, FMI-SALSA, GeosChem, GISS*, GLOMAP, GMI, GOCART, HadGEM, LSCE, OsloCTM, SPRINTARS, TM5, …) to various experiments (hindcast, direct/indirect forcing, …) TM5 contribution to AeroCom-1 by Maarten & Frank TM5 contribution to AeroCom-2 by Twan & Achim –HCA-IPCC (years 2000-2009), including target year 2006 –pre-industrial simulation (1850) –TM5 chem V3 with a few new features –AR5 (RCP4.5) emissions with natural/biogenic/soil/oceanic from MACCity

3. TM-Meeting Wageningen 2011-11-29 AeroCom-2: Diagnostics 0d (@ stations): –hourly means of full aerosol tracer information (2006) –daily means of full aerosol tracer information (1850, HCA) 1d (@ stations), vertical profiles: –daily means of of full aerosol tracer information, dry aerosol extinction & absorption PM10 (2006) 2d: –daily means of optical properties (1850, HCA): AOD @ {550,440,870}nm, fractions for {SO4,NO3,BC,OA,Dust,SS,H 2 O} fine-mode AOD, absorption AOD, asymmetry parameter, dry aerosol extinction / absorption PM10, ambient aerosol extinction –daily means of {emissions, surface concentrations, wet/dry deposition, load, nitrogen budget} (1850, HCA) –daily means of nitrogen budget (1850, 2006) –daily means of SW & VIS radiation fields (1850, 2006)  Twan 3d: –monthly means of extinction, absorption, asymmetry param., etc. –monthly means of full aerosol tracer information, etc. (1850, 2006)

4. TM-Meeting Wageningen 2011-11-29 AeroCom-2 Participating in the following studies: radiative forcing (Gunnar Myhre) all-aerosol-tracer (Graham Mann) organic aerosols (Kostas Tsigaridis) snow & ice radiative forcing (Mark Flanner) hindcast evaluation (Michael Schultz) … no active participation from KNMI foreseen Most striking result by TM5: Very low global mean AODs!

5. TM-Meeting Wageningen 2011-11-29 AOD

6. TM-Meeting Wageningen 2011-11-29 Revision 2 Bugs discovered: –SO 2 emissions high by a factor of 2 (SO 4 correct) –SeaSalt emissions low by a factor of 2 (mass) –NH3 emissions 20% low  re-run, re-submit to AeroCom database beforeafter

7. TM-Meeting Wageningen 2011-11-29 AOD against observations bias: -0.111

8. TM-Meeting Wageningen 2011-11-29 AOD fine mode against observations bias: -0.093

9. TM-Meeting Wageningen 2011-11-29 Absorption AOD against observations

10. TM-Meeting Wageningen 2011-11-29 Possible reasons 1.Sources for aerosols too low (emissions) 2.Sinks for aerosols too high (deposition, sedimentation)  lifetime! 3.Ageing and coagulation too fast in M7 (too few coarse particles) 4.Hygroscopic growth underestimated 5.Optics wrong 6.Combinations of 1. - 5. 7.…?

11. TM-Meeting Wageningen 2011-11-29 Possible reasons 1.Sources for aerosols too low (emissions) 2.Sinks for aerosols too high (deposition, sedimentation)  lifetime! 3.Ageing and coagulation too fast in M7 (too few coarse particles) 4.Hygroscopic growth underestimated 5.Optics wrong 6.Combinations of 1. - 5. 7.…? aerosol load / burden aerosol optical depth ?  opticsemissionslifetime  M7 nucl. / others?? sinks (wet/dry/sed) ?  M7 procs. / wet/dry/sed  emissions

12. TM-Meeting Wageningen 2011-11-29 Possible reasons 1.Sources for aerosols too low (emissions) 2.Sinks for aerosols too high (deposition, sedimentation)  lifetime! 3.Ageing and coagulation too fast in M7 (too few coarse particles) 4.Hygroscopic growth underestimated 5.Optics wrong 6.Combinations of 1. - 5. 7.…? aerosol load / burden aerosol optical depth ?  opticsemissionslifetime  M7 nucl. / others?? sinks (wet/dry/sed) ?  M7 procs. / wet/dry/sed  emissions

13. TM-Meeting Wageningen 2011-11-29 Check of the optics code Originally developed by Michael Kahnert (SMHI) Lookup-tables for {extinction, single-scattering-albedo, asymmetry-parameter} via –effective refractive index for each log-normal mode in M7 –count mean radius of mode (cmr) –wavelength (wl) Update by Maarten/Joost replacing (cmr & wl) by (cmr/wl) and production of a new lookup-table

14. TM-Meeting Wageningen 2011-11-29 Lookup-Table Revision Extinction coefficients –as a function of mode-radius –here: for 3 wavelengths and charact. refractive indices of Dust and SO4 –dashed lines: V1; solid lines: V2

15. TM-Meeting Wageningen 2011-11-29 Check of the optics code Originally developed by Michael Kahnert (SMHI) Lookup-tables for {extinction, single-scattering-albedo, asymmetry-parameter} via –effective refractive index for each log-normal mode in M7 –count mean radius of mode (cmr) –wavelength (wl) Update by Maarten Krol replacing (cmr & wl) by (cmr/wl) and production of a new lookup-table effective refractive index retrieved by mixing rules for internally mixed modes, crucial input: –refractive indices and densities of SO 4 /BC/POM/Dust/SeaSalt/H 2 O SO4SeaSaltBCDustPOMH2O refractive index OPAC* ECHAM-HAM Segelstein (1981) densities [kg/m 3 ] 184121652000265020001000 *) Hess et al, 1998

16. TM-Meeting Wageningen 2011-11-29 Check of the optics code Test(s): –update of densities, esp. carbon compounds, both in M7 and optics –update of optical properties of aerosol components Results: –increase of max. 10% for global mean AODs (July 2007) –change of AAOD not checked (BC) Higher sensitivity of AODs to mean particle radii, due to dependence of particle cross section and mass on r g –redistribution of particle mass and numbers!

17. TM-Meeting Wageningen 2011-11-29 Possible reasons 1.Sources for aerosols too low (emissions) 2.Sinks for aerosols too high (deposition, sedimentation)  lifetime! 3.Ageing and coagulation too fast in M7 (too few coarse particles) 4.Hygroscopic growth too low 5.Optics wrong 6.Combinations of 1. - 5. 7.…? aerosol load / burden aerosol optical depth ?  opticsemissionslifetime  M7 nucl. / others?? sinks (wet/dry/sed) ?  M7 procs. / wet/dry/sed  emissions

18. TM-Meeting Wageningen 2011-11-29 Global mean burdens Comparison with “products” that capture observed AOD frequency distribution: –TM5 (year 2006) –GOCART (year 2006) –HadGEM2 (year 2006) –OsloCTM2 (year 2006) –AeroCom-1 (year 2000) Importance ranking (partial AOD): –SO4 (20-40%) –SeaSalt (15-40%) –Dust (15-30%) –POM (10-30%) –BC ( 0- 5%) Main problem: No unique model reference available…

19. TM-Meeting Wageningen 2011-11-29 Example: SO4 zonal means sconc emiwetdep load

20. TM-Meeting Wageningen 2011-11-29 Example (cont.): SO4 characteristic times lower sink terms in GOCART / OsloCTM higher chemical production also possible for GOCART / OsloCTM [d]TM5AeroCom1GOCARTOsloCTM burden / emissions 120110162252 burden / deposition 4.634.345.687.90

21. TM-Meeting Wageningen 2011-11-29 Summary SO4: Surface concentrations good (NH-midlat.), loads on the low side Rather high sink terms (wetdep), esp. in the tropics SeaSalt: Despite doubling the emitted mass, the load is still low Rather high sink terms (wetdep) Dust: Loads on the low side Rather high sink term POM: Loads on the low side (SOA!) Rather high sink terms (wetdep), esp. in the tropics and the NH BC: Surface concentrations good, loads on the low side Rather high sink terms (wetdep), esp. in the tropics

22. TM-Meeting Wageningen 2011-11-29 Con(cl/f)usion Low loads cause low AODs, but presumably the masses can NOT explain the AODs being low by ~50%... More likely due to wrong size distributions, so are they correct –in M7 (water uptake / coagulation)?? –in the emissions (radii & masses specified)?? Size distributions interact with removal processes (deposition, sedimentation). Very low fine mode AOD another hint on wrong particle size distribution. M7 nucleation/condensation is a very critical process, as seen by the effect of reducing SO2 emissions (H2SO4 precursor).

23. TM-Meeting Wageningen 2011-11-29 Outlook Principle check of removal processes –previous problems known (aan de Brugh, 2010) –first analysis already done for wetdep –adaptation of more sophisticated approaches planned (e.g., ECHAM- HAM; Croft et al., ACP, 2010; ) –especially: wet removal of number and mass individually usage of current mode radii instead of predefined ones take into account cloud type for in-cloud scavenging … –… Check of emission routines and underlying assumptions desirable as well

24. TM-Meeting Wageningen 2011-11-29 Dust emissions: Introduction So far: module by Elisabetta Vignati (presented June 2008) –Offline production of daily emissions using ECMWF meteo fields Algorithm is based on Tegen et al. (JGR, 2002) –definition of possible dust uptake areas: calculation of the distribution of potential vegetation types (biomes) non-forest biomes are considered as potential source –usage of normalised difference vegetation index (NDVI) to derive global fraction of absorbed photosynthetically active radation (FPAR) –“shrinking” of available uptake area in case of grass dominated vegetation (FPAR!) shrub dominated vegetation (FPAR!) snow cover –supressing dust uptake when soil moisture exceeds a certain threshold –vertical particle flux from soil properties (size distribution, alpha) and surface wind stress u* (derived from 10m wind speed)

25. TM-Meeting Wageningen 2011-11-29 Dust emissions: Offline Implementation 1.Parameters not dependent on time and grid cell o Properties of soil size distribution based on soil population and texture 2.Parameters calculated on daily basis o Snow cover from snow depth o Areas of emissions using potential sources, vegetation, cultivation, lsm, fpar (and moisture) 3.Parameters calculated on 3 hourly basis o Surface stress from wind speed  fluxes o Mapping from emission bins (24) to TM5 modes (2: insoluble accumulation and coarse) from presentation by Elisabetta

26. TM-Meeting Wageningen 2011-11-29 Dust emissions: Input Parameters Soil type and size distribution Preferential dust source areas (paleolakes) Fraction of absorbed Photosynthetically Active Radiation (FPAR) Cultivation Surface roughness length Vegetation type Snow depth Surface wind speed soil moisture from Ina Tegen ECMWF fields from presentation by Elisabetta

27. TM-Meeting Wageningen 2011-11-29 Using Soil ph Dust emissions: Vegetation types from presentation by Elisabetta

28. TM-Meeting Wageningen 2011-11-29 Dust emissions: Input Parameters

29. TM-Meeting Wageningen 2011-11-29 Dust emissions: Results for 2000 from presentation by Elisabetta

30. TM-Meeting Wageningen 2011-11-29 However, (revised) online version desirable/needed for EC-Earth/TM5

31. TM-Meeting Wageningen 2011-11-29 Online dust emissions: What’s new? Adaptation to TM5-chem-V3 Input parameter now in one single NetCDF file Reformulation of the uplift area as a function of FPAR Lowered hard constraint of LSM == 100 to LSM > 99 Removed uninitialised parameters, speed optimisation, OpenMP Identical offline & online version available

32. TM-Meeting Wageningen 2011-11-29 Online dust emissions: Evaluation AeroCom-1 median GISSHadGEMSPRINTARSOsloCTM (year 2006) MPIHAMv2 (year 2006) dust emissions [Tg/yr] 11261110297225961420792 Source: http://aerocom.met.no/

33. TM-Meeting Wageningen 2011-11-29 Online dust emissions: Evaluation

34. TM-Meeting Wageningen 2011-11-29 Outlook Implementation of soil moisture Evaluation of load, AOD etc. compared to usage of Ginoux (median particle size!) Replacement of input fields by EC-Earth parameters

35. TM-Meeting Wageningen 2011-11-29 Decadal runs with EC-Earth/TM5 2000-2009/10 and 2025-2035 offline and online simulations with TM5 offline: small pre-processor developed to use EC-Earth CMIP5 output for TM5 online: CMIP5 restart files for EC-Earth/TM5 base case: ERA-Interim driven TM5 simulations 2000-2009 first results for ERA-I (full period) vs. EC-Earth (2000-2002)

36. TM-Meeting Wageningen 2011-11-29 EC-Earth/TM5: SO4

37. TM-Meeting Wageningen 2011-11-29 EC-Earth/TM5: Decadal runs 2000-2009/10 and 2025-2035, (2060-70) offline and online simulations with TM5 and EC-Earth/TM5, resp. offline: small pre-processor developed to use EC-Earth CMIP5 output for TM5 online: CMIP5 restart files for coupled EC-Earth/TM5 base case: ERA-Interim driven TM5 simulations 2000-2009 first results for ERA-I (full period) vs. EC-Earth (2000-2002) Outlook Evaluation of inter-annual variability, extreme events, etc. by comparison with observations (current climate) Assessment of climate impact on (aerosol) chemistry by comparing the two (three) time slice experiments