Transcript Modelling Capabilities for Aerosols and Climate at CCCma Knut von Salzen Canadian Centre for Climate Modelling and Analysis (CCCma) Environment Canada, Victoria, British.

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)
[email protected]
www.cccma.ec.gc.ca
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
Large Increases in Black Carbon Emissions
from Human Activities
Future
(Moss et al., 2010)
Historic
(Lamarque et al., 2010)
FSU
N America
Europe
RCP6.0
RCP8.5
S+E Asia
Anthropogenic
RCP2.6
Other
Vegetation
Fires
FSU
N America
Europe
S+E Asia
Other
RCP6.0
RCP2.6
RCP8.5
Black Carbon Sources + Sinks in CanESM4.2-PAM
BC
BC
24 hrs
BC
BC
hydrophilic
hydrophobic
Land
Ocean
Aerosol Microphysical Processes in CanAM4.2
inorganic & organic
vapours
condensation
nucleation
& coagulation
Sources
mechanical production
(sea salt, mineral dust)
emissions
coagulation
& condensation
dry deposition
Sinks
gravitational
settling
wet deposition
approx. dry particle
radius (µm)
Droplet Activation and Growth
cloud layer
supersaturation (%)
height (m)
supersaturation (%)
adiabati
c
air
parcel
Water-insoluble
organics in aerosol
height (m)
Water-soluble
organics in aerosol
CDNC (m-3)
updraft wind speed
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)
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
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 albedo
Diffuse trans
Grain size (microns)
Means for
0.2-0.69 microns,
black surface,
θ=0o
SWE (kg/m2)
SWE (kg/m2)
Improved Simulation of Cloud Droplets and Aerosol Forcings
CanAM with aerosol microphysics
Cloud Droplet Number
Concentration in low Clouds
for JJA
CanAM with bulk aerosol scheme
Satellite observations
Obs: MODIS, 2001
(Bennartz, pers. comm.)
droplets/cm3
Parameterizations for Snow Microphysics
snowfall
Atmosphere
BC dry + wet
deposition
Surface Snow Layer
dry + melt-freeze
metamorphism
BC melt water
scavenging
Clear-Sky Planetary Albedo Biases
March-April-May (MAM)
New snow albedo
parameterization
Improved biases from
new parameterizations
for snow albedo
CLASS 3.6
(Anomalies vs. CERES
EBAF V2.7, 2003-2008,
masked by modelled SWE)
June-July-August (JJA)
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 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).