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)

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) 1 st and 2 nd aerosol indirect effects, using online non-adiabatic parcel model Absorption of solar radiation by black carbon in cloud droplets Canadian Atmospheric Global Climate Model (CanAM4.2)

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

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

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

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

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 Summary of Plans for Aerosol and Climate Modelling

- 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 SWE (kg/m 2 ) Grain size (microns) Diffuse albedo Diffuse trans Parameterization of Snow Albedo Means for microns, black surface, θ=0 o

droplets/cm 3 Cloud Droplet Number Concentration in low Clouds for JJA Obs: MODIS, 2001 (Bennartz, pers. comm.) Improved Simulation of Cloud Droplets and Aerosol Forcings Satellite observations CanAM with aerosol microphysicsCanAM with bulk aerosol scheme

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

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

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)

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

Extended Canadian Earth System Model (CanESM4.2-PAM) Under development. Frozen model expected to become available Oct 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/SO 4. 1 st and 2 nd 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).