Modelling Capabilities for Aerosols and Climate at CCCma Knut von Salzen

1. Modelling Capabilities for Aerosols and Climate at CCCma Knut von Salzen Canadian Centre for Climate Modelling and Analysis (CCCma)‏ Environment Canada, Victoria, British Columbia, Canada Acknowledgements: M. Namazi, J. Li, J. Cole, J. Scinocca, J. Fyfe, N. Gillett (CCCma) W. R. Leaitch, S. Sharma, L. Huang (CCMR, Environment Canada) A. Herber (AWI Bremerhaven) knut.vonsalzen@ec.gc.ca www.cccma.ec.gc.ca

2. Canadian Atmospheric Global Climate Model (CanAM4.2) General features • Resolution: T63 (ca. 2.8°), 49 levels to approx. 1hPa • Spectral advection, hybridization of tracer variable, physics filter • Orographic and non-orographic gravity wave drag • Radiation: Correlated-k distribution and Monte carlo Independent Column Approximation (McICA) methods • Local and non-local turbulent mixing • Mass flux schemes for deep and shallow convection • Prognostic cloud liquid water and ice, statistical cloud scheme New features • Most recent version of the CLASS land surface scheme (version 3.6) • Parameterizations for snow microphysics and snow albedo • Prognostic aerosol microphysics (size distributions) for sulphate, sea salt, mineral dust, hydrophobic and hydrophilic black and organic carbon • Improved direct radiative aerosol forcings (internally mixed aerosol) • 1st and 2nd aerosol indirect effects, using online non-adiabatic parcel model • Absorption of solar radiation by black carbon in cloud droplets

3. Large Increases in Black Carbon Emissions from Human Activities Future (Moss et al., 2010) Historic (Lamarque et al., 2010) FSU N America Europe S+E Asia Other RCP6.0 RCP2.6 RCP8.5 Anthropo- genic Vegetation Fires FSU N America Europe S+E Asia Other RCP6.0 RCP8.5 RCP2.6

4. BC BC BC Black Carbon Sources + Sinks in CanESM4.2-PAM BC 24 hrs hydrophilic hydrophobic Land Ocean

5. Aerosol Microphysical Processes in CanAM4.2 inorganic & organic vapours condensation Sources nucleation & coagulation mechanical production (sea salt, mineral dust) emissions coagulation & condensation approx. dry particle radius (µm) gravitational settling dry deposition wet deposition Sinks

6. Droplet Activation and Growth Water-insoluble organics in aerosol Water-soluble organics in aerosol cloud layer height (m) supersaturation (%) supersaturation (%) adiabatic air parcel height (m) CDNC (m-3) 25 cm/s 50 cm/s 100 cm/s 200 cm/s Circles: New numerical solution Bullets: Detailed parcel model (Shantz and Leaitch) updraft wind speed CDNC (m-3)

7. Summary of Plans for Aerosol and Climate Modelling • Analysis of radiative forcings of different types of aerosol in CanAM4.2 by emission region and sector • Validation of temporal variability in simulated aerosol concentrations on multi-year and seasonal time scales using surface observations • Validation of vertical profiles and horizontal BC concentration distributions based on aircraft observations • Analyze roles of biomass and fossil fuel emissions for black carbon concentrations through comparisons with isotopic data • Investigate contributions of Arctic DMS emissions to aerosol burdens • Detection and attribution of changes in Arctic climate to changes in aerosol emissions • Climate mitigation scenario simulations for black carbon

8. Parameterization of Snow Albedo • Lookup table function of: SWE, underlying surface albedo, solar zenith angle, snow grain size, BC concentration, wavelength interval - Diffuse albedo, direct albedo, diffuse transmission, and direct transmission • Single layer of snow over bare ground (consistent with CLASS) • Detailed offline DISORT calculations at 280 wavelengths. Results averaged over CCCma solar radiation bands - Total albedo for each band is weighted average (based on incident radiation) of direct and diffuse albedo Diffuse trans Diffuse albedo Grain size (microns) Means for 0.2-0.69 microns, black surface, θ=0o SWE (kg/m2) SWE (kg/m2)

9. Improved Simulation of Cloud Droplets and Aerosol Forcings CanAM with aerosol microphysics CanAM with bulk aerosol scheme Satellite observations Cloud Droplet Number Concentration in low Clouds for JJA Obs: MODIS, 2001 (Bennartz, pers. comm.) droplets/cm3

10. Parameterizations for Snow Microphysics BC dry + wet deposition Atmosphere Surface Snow Layer snowfall dry + melt-freeze metamorphism BC melt water scavenging

11. Clear-Sky Planetary Albedo Biases March-April-May (MAM) June-July-August (JJA) New snow albedo parameterization CLASS 3.6 Improved biases from new parameterizations for snow albedo (Anomalies vs. CERES EBAF V2.7, 2003-2008, masked by modelled SWE)

12. Simulation of Multicomponent Aerosols with the PLA Aerosol Model (PAM) Example from application of PAM in a developmental version of the Canadian atmospheric global climate model (CanAM4-PAM)

13. Effects of Aerosols on Clouds & Climate more reflection: Cloud albedo effect less precipitation: Cloud lifetime effect ● ● ● ● ● ● ● The strength of aerosol radiative forcings from aerosol/cloud interactions depends on how strongly cloud droplet concentrations respond to changes in aerosol concentrations ● ● ● ● ● ● ● ● ● ● ● ● ● ● cleanpolluted ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●

14. Extended Canadian Earth System Model (CanESM4.2-PAM) • Under development. Frozen model expected to become available Oct 2013. • Developmental atmospheric component: CanAM4-PAM. • Fully coupled 3D model for atmosphere, land surface, ocean, cryosphere, and carbon cycle. • Resolution in atmosphere: T63 (ca. 2.8°), 49 levels to approx. 1hPa. • Spectral/hybrid representation of large-scale advection of tracers. • Prognostic aerosol size distributions for Sulphate, sea salt, mineral dust, hydrophobic and hydrophilic black and organic carbon using interactively coupled Piecewise Lognormal Approximation (PLA) Aerosol Model (PAM). Standard aerosol processes: Emissions, transport, dry and wet deposition, coagulation, binary homogeneous nucleation, chemical production for clear- and cloudy-sky. • Interactive direct radiative calculations for internally mixed hydrophilic BC/OC/SO4. • 1st and 2nd indirect effects using online non-adiabatic parcel model. • Absorption of solar radiation by BC in cloud droplets. • New parameterization for absorption of solar radiation by BC in snow based on tabulated, pre-calculated albedo and prognostic parameterization for BC snow concentration and grain size (single layer).