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

3. RCM/GCM Interactions: Model 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 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

4. RCM/GCM Interactions: Model Development Examples For example, AOMIP / ARCMIP have highlighted areas in need of improvement or inclusion in GCMs –Cloud processes –Tidal mixing –Etc. For example, AOMIP / ARCMIP have highlighted areas in need of improvement or inclusion in GCMs –Cloud processes –Tidal mixing –Etc. Wyser et al., 2008

5. Model Developments: Cautions 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 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

6. RCM/GCM Interactions: Coordinated Experiments Provides scientifically interesting collaborative efforts Facilitates communication across RCM/GCM communities Enables scientific investment in joint RCM/GCM studies Provides scientifically interesting collaborative efforts Facilitates communication across RCM/GCM communities Enables scientific investment in joint RCM/GCM studies

7. 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) 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) Polyakov et al., 2005 Arctic Ocean change Ocean Heat Transport to Arctic

8. 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 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 Arctic Amplification Reduced Warming IPCC-AR4 Models SRES-A1B

9. 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? 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? Sept Ice Extent Observed Simulated

10. 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) 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) Courtesy IARC, Dave Sanches Coastal erosion

11. 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? 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?

12. 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? 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?