An update on AC&C activitiesPhil Rasch, Martyn Chipperfield, Sarah Doherty, A. R. RavishankaraRavi stepped down, Martyn replaced himProgress reportDiscussion/Advice on ActivitiesAncillary Activities
Atmospheric Chemistry and Climate: TimelineSummer/Fall, 2007: AC&C Activity plans developed AC&C liaisons initiate coordination with AeroCom, CCMVal, HTAPMarch 2008: Conference call of AC&C Steering Committee Review/discussion of activity plans (for 3 of 4 activities) Agreement to arrive at workshop with detailed model run plans & example model run outputJune, 2008: 2nd AC&C Workshop, joint w/ HTAP (Washington, D.C.) Finalize activity model runs with engagement of all model groups, in close coordination with HTAP next phase plansThe Path Forward:Mid-2008 2009: Model runs, publicationsLate 2009: Models are frozen for next IPCC Assessment
Revising the paradigm: (Phils opinion)No longer preparing models to be used for IPCC runs, but.Design, Facilitate, Coordinate some of runs relevant to IPCC,
Activity 1: 20 year HindcastPeter Hess, Jennifer Logan, Oliver Wild
Activity 2: What controls the vertical distribution of species. Step 1: Focus on 5 km -> tropopauseJos Rodriguez, Joyce Penner, Cline Mari, (CCMVal Andrew Gettelman?)
Activity 3: Cloud-chemical interactionsCurrently on hold & (possibly) being re-defined
Activity 4: Future Scenarios: Sensitivities & UncertaintiesDrew Shindell, J-F Lamarque, Michael Schulz, (CCMVal Veronika Eyring)AC&C Initiative: Activities for Phase INeeds Resuscitation at a later time
Activity 1: Hindcast Experiments
Needed a coordinator/facilitator (e.g. some funding)Just lined up Contributions from NASA, DOE, NOAA, EPA for a post-doc/research associate for 2 years
We did not propose a single hindcast experiment from 1980 But, a series of interrelated experiments
Each hindcast experiment defined by: a multi-year series (post-1980) a clear objective grading criteria for evaluating model success. a set of required diagnostics to facilitate model comparison and evaluation.multi-year external forcings (e.g., emissions) needed to drive the simulations.guidelines on the types of chemical models and meteorological fields that can usefully participate
Activity 1: Simple Tracer Hindcast (C. Nevison, M. Prather, N. Mahowald)Goal: Match the trends and variability of the nearly-inert trace gases CFCs and N2O as measured by stations of the ALE/GAGE network. Quantify importance of: -changing emissions-tropospheric meteorology-stratosphere-troposphere exchange variability.From Nevison et al., Interannual Growth Rate Anomalies: Match and AGAGE
Activity 1: Aerosol Hindcast(Michael Schulz, Mian Chin)Goals: Better understanding of:-regional and global satellite observed trends in AOD-regional differences in sulfate and black carbon deposition from the Arctic to the Alpes-temporal trends in aerosol concentration, composition, optical properties and deposition-emission trends of primary aerosols and aerosol precursor gazes-the impact of changing meteorology vs changing emissions on aerosol trends-dimming and brightening trends observed by surface radiation networks-the evolution of the anthropogenic aerosols perturbation of the Earth radiative balance
To be run as part of AEROCOM
FromRamanathan et al., 2005
Observed and simulatedSurface RadiationFluxes over India
Activity 1: Ozone Hindcast(Jennifer Logan, Peter Hess)From Ordonez et al.
Interannual OzoneVariations and trends.Goals: quantify impact on tropospheric ozone of:
-changes in emissions of ozone precursors (NOx, CO, hydrocarbons)-changes in methane-changes in ozone in the lower stratosphere-dynamical variability including STE, ENSO, NAO/AO
From Wang et al, Modeled and Observed changes in CH4 growth rate.Goal: Match the observed methane trends and variability.Quantify: -the importance of changing anthropogenic and natural emissionsthe importance of OH variations. Procedure: use OH fields from the ozone hindcast in an inverse modeling calculation for methane emissions reconcile top-down and bottom-up emission estimates.
Activity 1: Methane Hindcast (I. Bey, F. Dentener, A. Fiore, P. Hess, P. Bergamaschi)
AC&C Initiative, Activity 1: Hindcasts
For models with whole atmosphere chemistry needs to build on recent CCMVal REF-B1 simulations (1960-2005). Full chemistry specifications need to include stratospheric forcings and boundary conditions. Default is to take REF-B1 input.As stratospheric model runs should start ~1960, tropospheric emissions need to be prescribed from this date.
AC&C Activity 4 Future ScenariosDrew Shindell, J-F Lamarque, Michael Schulz, (CCMVal Veronika Eyring)Phase 1: ACC-MIP (focus on troposphere)Time-slice experiments to complement AR5; CCMs and CTMs (need stratosphere)
Emission sensitivity studiesSensitivity to IAM modeling of specific RCPSpread from using climatologyTimeslice runs including detailed chemistry diagnostics and separating aerosol indirect effects. Each run 4 years with prescribed SSTs taken from AR5 runs (SSTs should ideally be decadal means around given years), 2-month initialization suggested.
8 historical times (1850I, 1890, 1910, 1930, 1950 I, 1970, 1990, 2000 I)
5 future times (2010 I, 2030, 2050 I, 2070, 2100 I), each with 2.6 W/m2 Representative Concentration Pathway (RCP), 4.5 W/m2 RCP and 8.5 W/m2 RCP.
AC&C Activity 4Phase 1: ACC-MIPTimeslice experiments to complement AR5 (38 simulations, 160 years)Emission sensitivity studies
Sensitivity to IAM modeling of specific RCPSpread from using climatologyRun at year 2050 (SSTs from #1), 1 year runs (+2-month initialization), models own distribution of given emission scaled uniformly:2.1: +100 Tg isoprene2.3: +20% biomass burning (all species)2.4: +50 Tg methane (3 year run in this case, only applicable for models with sources/sinks of methane rather than prescribed)2.5: +2 Tg N/yr lightning NOx
AC&C Activity 4Phase 1: ACC-MIPTimeslice experiments to complement AR5 (38 simulations, 160 years)Emission sensitivity studiesSensitivity to IAM modeling of specific RCP
Spread from using climatologySame 4 year timeslice runs as in ACCMIP_1 for 2050 and 2100 but using emissions for the 2.6 and 4.5 RCPs from the other available IAMs. Runs without AIE only (as these are not climate runs)
What controls species distribution between 5km & tropopause?:Advection by large-scale winds Convection Wet scavengingDry DepositionStratosphere-Troposphere Exchange (CCMVal, SPARC)ChemistryIn situ production of ozone precursors
-Start off looking at convection and scavenging processes, as these are the most uncertain and biggest knobs in the models, in particular when looking at UT.
AC&C Initiative, Activity 2: Vertical Distributions Jos Rodriguez, Joyce Penner, Cline Mari, (SPARC representative AG?)
Activity 2 What to do?Most of the discussion initiated by senior people with little time but lots of opinions/ideasNeed heroes -- people who actually get things donePerhaps recent relevant activities may be exploited to enhance this activity.CCMValSCOUT-O3Mary Barths convection intercomparison activityAMMA
AC&C Initiative, Activity 2: Vertical DistributionsSCOUT-O3 Results (Hoyle et al 2009)Idealised tracers (e.g. 5-day lifetime)Comparison with Darwin CO profilesComparison of CTMs, CCMs and mesoscale models
Activities triggered and related to AC&C
EmissionsAn international effort was made to provide improved emissions 1850-2300, consistent across 2000 for anthropogenic (including shipping and aircraft) and biomass burning of reactive gases (not ODSs) and aerosolsHistorical (1850-2000) gridded anthropogenic and biomass burning emissions of reactive gases and aerosols: methodology and application.Jean-Franois Lamarque, Claire Granier, Tami C. Bond, O. Cooper,.Veronika Eyring, Angelika Heil, Mikiko Kainuma, Z. Klimont, David Lee, Catherine Liousse, J. R. McConnell , Aude Mieville, S. Oltmans, Bethan Owen, D. Parrish. Keywan Riahi, Martin Schultz, Drew Shindell, Steven Smith, Elke Stehfest, Allison Thomson, John Van Aardenne, Detlef Van Vuuren,
StatusEmissions1850-2000: available since July for all reactive gases and aerosols (1850 and 2000 earlier)2000-2100: RCP4.5/RCP8.5 available for reactive gases and aerosolsConcentrations (decadal averages): atmosphere-only simulations1850-2000: ozone (V. Eyring)1850-2000: aerosols (including dust and sea-salt) to be made available soon.2000-2100: RCP4.5/RCP8.5 running (NCAR)(Phil thinks) At least one RCP scenario still missing
Example of Impact of emissions(older versions, Flanner, McConnell and Rasch, unpublished)
Newer Emissions (Lamarque and Flanner, unpublished)
Remaining IssuesCCMVal desire to start hindcasts in 1960sTrop focus started in 1980sHindcasts for troposphere would benefit from emissions with annual time scale resolution (or shorter)E.g. fires?
*Atmospheric growth rate anomalies for MATCH model results (black line; note that at MaceHead, MATCH CFC-11 and CFC-12 (dash-dotted lines) have been divided by 5 to keep them on scale)and AGAGE data (gray line). (top) N2O, (middle) CFC-11, and (bottom) CFC-12. (a, f, k) Cape Grim.(b, g, l) Samoa. (c, h, m) Barbados. (d, i, n) Trinidad Head. (e, j, o) Mace Head.
Follows from early experiments by a number of groups to calibrate models. *Simulated, observed annual mean solar fluxes for india at the surface. *12-month running means of the normalizedmonthly anomalies with respect to the 19922004 meanannual cycle of lower free tropospheric ozone (blue) at(top) Jungfraujoch and (bottom
