How can regional coupled arctic modeling efforts best interact with the global climate modeling community?

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How can regional coupled arctic modeling
efforts best interact with the global climate
modeling community?

• Marika Holland, NCAR
• Cecilia Bitz, U. Washington
• Dave Bailey, NCAR
• Elizabeth Hunke, LANL
• Dave Lawrence, NCAR
• Steve Vavrus, U. Wisconsin

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RCM/GCM InteractionsModel Developments

• Regional Arctic models focus on polar specific
  improvements
• Can help inform/feed back into global modeling
• Can allow studies on the global climate
  impacts/feedbacks of these polar processes
• Development efforts need to be aware of influence
  on climate sensitivity, compensating errors
  (sometimes of omission)
• RCM intercomparisons can identify things of
  interest to GCMs

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RCM/GCM InteractionsModel Development Examples

• For example, AOMIP / ARCMIP have highlighted
  areas in need of improvement or inclusion in GCMs
• Cloud processes
• Tidal mixing
• Etc.

Wyser et al., 2008
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Model DevelopmentsCautions for Global
Applications

• Must be generalized to work globally
• Must work in all climate regimes, in space and
  time (generally will not use regionally specific
  parameterizations)
• Should not improve the Arctic at the expense of
  other regions
• Polar specific improvements need to work in the
  southern hemisphere
• Heat/Water conservation issues

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RCM/GCM InteractionsCoordinated Experiments

• Provides scientifically interesting collaborative
  efforts
• Facilitates communication across RCM/GCM
  communities
• Enables scientific investment in joint RCM/GCM
  studies

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Coordinated Experiments Examples

• Importance of local versus remote forcing for
  Arctic climate conditions
• GCM forcing of a regional model for different
  scenarios BGC studies along these lines
  (chemical transports, etc.)?
• Use RCM to study influence of boundary
  perturbation on system (e.g. pulse-like ocean
  heat transport perturbation)

Arctic Ocean change
Ocean Heat Transport to Arctic
Polyakov et al., 2005
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Coordinated Experiments Examples

• Mechanisms driving Polar Amplification
• Under the same boundary forcing (from 1 or
  multiple GCMs), what range of polar amplification
  is simulated by RCM due to internal
  parameterization changes

IPCC-AR4 Models SRES-A1B
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Coordinated Experiments Examples

• Use RCM to investigate events simulated in a
  GCM under different forcing scenarios
• For example, rapid ice loss and the mechanisms
  that drive that loss (role of ocean, clouds,
  etc.)
• Does an RCM with higher resolution/improved
  Arctic processes simulate a different response?

Observed
Simulated
Sept Ice Extent
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Coordinated Experiments Examples

• Arctic climate impacts
• Provide forcing from a GCM (e.g. sea level rise)
• Use RCM to investigate the effects on processes
  that are not included in the global model (e.g.
  coastal erosion)

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Logistics to facilitate RCM/GCM interaction

• Communication
• Participation at meetings, on working groups,
  through coordinated experiments, others
• Some similar base model components?
• Would allow easier interactions and integration
  of model development efforts
• Joint Participation in MIPS? (Lessons from
  AOMIP?)
• Others?

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Discussion

• Model development activities, coordinated
  experiments, active communication could all
  facilitate interaction between RCM/GCM
  communities
• Others mechanisms to facilitate interaction?
• Interest in coordinated experiments - possible
  short list of interesting problems?
• GCM component models and their applicability for
  RCMs?