uncertainty quantification (uq) and climate change talking points mark berliner, ohio state issues...
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Uncertainty Quantification (UQ) and Climate Change Talking PointsMark Berliner, Ohio State
Issues of continuing interest:
Models, Data, Impacts & Decision Support
1) Disclaimers
a) List is incomplete
b) None are criticisms, just questions and suggestions
c) Please let me know what I missed
2) My Apologies for missing the workshop
Models We know many sources of uncertainty:parameterization; feedbacks; resolution &approximation; nonlinearity; etc. How to help?• Continued model assessment • Claim that models and observations “line up”
needs quantification• Since a key is the response of hydrological cycle,
do real advances require increased resolution?• Multi-model ensembles• Bigger ensembles vrs better models (allocation of
computational resources) • Do more models lead to more confusion?• Lot’s of opportunities for collaboration (both design and
analysis)!!!!
Data1) Paleoclimate: Lot’s of very important work to do: • Assess impacts of forcings without sole reliance on
climate models, though we need to “know” the historical impacts and the forcings.
• Use of proxies is key opportunity for collaboration• Aid in assessment/improvement of the models1) Combining datasets: rebuilding climate variable
global estimated fields w/ uncertainties (eg, temperature fields)
2) Modern climate monitoring: design and use of remote sensing, etc. (“compute” or observe)
3) Operational system for scientists and decision makers to access info on the “state of the planet”
Impacts1) Level I: Sea level; Storms, droughts,
hurricanes; Weather extremes; Fire; Floods; Other environmental systems
2) Level II: Human activities, agriculture, health, economics, national security
3) A viewpoint: hierarchical chains • Global to regional impacts: downscaling
a) Dynamic b) Statistical c) Combinations
Excellent opportunity!!!• Propagation of uncertainty• Collaboration across many disciplines (Level II)
Global vrs
Regional Behavior
Annual mean
precip (cm) 1980-1999: Observed
& simulated based on
multi-model mean.
Figure 8.5
Global vrs
Regional Behavior
Annual mean
precip (cm) 1980-1999: Observed
& simulated based on
multi-model mean.
Figure 8.5
Propagation of uncertainty: (causal) chains
CO2 __> global climate
__> regional climate
__> local weather and hydrological
environment
__> disease patterns
crop yields; etc.
None of these arrows are deterministic or “known”. Rather we need to build probability models for each and then link them. This is where statisticians are expert.
Remark: feedbacks can be very tough.
Decision Support
• Ranges (intervals) vrs probability dist.When are “honest” confidence/prediction intervals too wide to be a value?
• Risk analysis (expected loss) • Explaining/using UQ: “uncertainty is not
ignorance”• Presenting results in useful forms• Sensitivity, robustnessRemark: Some don’t like this area, but it is
being done; I think we should participate!!
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