Transcript Next Steps and plans for coupling with other model

CAM Microphysics
Development Group
Next Steps
Gettelman, Morrison, Neale
Ghan, Mitchell, Hess, Rasch
Current Status
• Initial implementation of moment scheme
– ‘Modified Morrison Microphysics’
– Initial CAM Runs & Column model
• Runs
• Conserves energy & Mass (we think)
Conceptual Issues
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Biases relative to observations
Subgrid vertical velocity
Diagnostic v. Prognostic Precip
Bergeron Process (Vapor Deposition)
Ice Nucleation / Supersaturation (Liu)
Cloud fraction v. In-cloud part
– Use current CAM closure for last 2
– Future options are PDF and/or [Mc]ICA
Engineering Issues
• Detailed Timing (by process)
– Optimization
– Will wait on other components for ‘tuning’
• Generalize as WRF scheme?
• Other components:
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Sub-grid vertical Velocities
Hook up to aerosol scheme in CAM
Nucleation of aerosols (Ghan)
Pace radiation development
Convective detrainment of #
Use ‘critical’ pieces in PBL & Convection?
w’,c, qc
Convection
(w,MF,qc)
Convective
Detrainer
#,m (aerosol)
Droplet
Activation
Cloud
Fraction
qcx2,qix2
f, qc,s
Macro-micro interface?
Microphysics
(qcx2,qix2,qv)
#,m,type
Ice
Activation
ICA
Optics
Radiation
w’
w’
Turbulence
Gravity Wave
Drag
dT,dQ,df
Aerosols
&
We build
Other
(tendencies)
Precip(x2),Snow
DMa,D#qc
‘Wiring’ Experiment: Microphysics
Interaction with: Radiation
• Currently passing Rei & Rel to Radiation
• Optical package as interface
– Not just mean, distribution
• Independent column approximation
– Consistent subcolumns (McICA Pincus/Hannay)
• Optics Implementation:
– Mitchell (microphysics)
– Collins (radiation)
Interaction with: Cloud Fraction
• New proposals for cloud fraction (Johnson)
– ‘modified’ Slingo: no ‘empty’ clouds
– Simplified Tompkins scheme: 2 moments
• Evaluate Microphysics w/ schemes
– ‘empty’ cloud may be big issue
– (high cloud fraction, low cloud water)
– New closure assumption on total water
• Development by:
– Gettelman/Hack/Johnson (met office)
Interaction with: Convection
• What microphysics is in convection?
• Detrain mass and number?
• Aerosol/tracer bookkeeping in
convection
• Implementation By:
– ‘Convective Group’ (Rasch/Donner)
Interaction with: Others
• Subgrid vertical velocity critical
– New parameterization based on TKE,GW?
– GW, PBL schemes
– Now just specified, invariant
• What have we missed?
– Surface flux issues?
Interaction with: Aerosols
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Morrison uses Ghan activated aerosols
Interact with Ghan activation scheme
Scavenging & Bookkeeping of mass
Implementation by: Ghan
Other Aerosols?
Scavenging?
Next Steps
• Parallel Development
– Microphysics
– Interactions with components
• Priorities:
– Summer-Fall 2006
• Stabilize Morrison code framework
• ‘Conceptual’ & ‘engineering’ issues
• Subgrid vertical velocities
– Fall 2006:
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Go/No Go decision (or revert to Plan B)
Evaluation v. Observations
Pace other components (Cld fract, Radiation)
Get aerosols ‘interactive’
• Are these the right priorities?
Discussion Questions
• Hugh/Rich: What did I miss?
– Comments from David, Steve, Peter, Phil
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Does this look Reasonable?
Are these plans reasonable?
Conceptual Issues for Aerosols?
How do we begin evaluation v. obs?