1. Climate Change Results National Center for Atmospheric Research
NARCCAP Second
Users’ Meeting
Overview of
Climate Change Results
Linda O. Mearns
National Center for Atmospheric Research
Boulder, CO
September 10-11, 2009

2. NARCCAP PLAN – Phase II A2 Emissions Scenario MM5 RegCM3 CRCM HADRM3
GFDL
CGCM3
HADCM3
CCSM3
GFDL
Time slice
50 km
CAM3
Time slice
50km
current
Provide boundary conditions
future
Interesting problem to determine expected relationship between time slice experiments and AOGCM runs and with RCMs using the same
AOGCM boundary
MM5
Iowa State
RegCM3
UC Santa Cruz
CRCM
Quebec,
Ouranos
HADRM3
Hadley Centre
RSM
Scripps
WRF
PNNL

3. GCM-RCM Matrix AOGCMS RCMs GFDL CGCM3 HADCM3 CCSM MM5 RegCM CRCM HADRM
RSM
WRF
*CAM3
*GFDL
X**
1 = chosen first GCM
*= time slice experiments
Red = run completed
** = data loaded
RCMs
We use a fractional factorial design – so each Global model provides boundary conditions for 3 RCMs, and each RCM uses two different AOGCMs. Red indicated simulations that are completed. Both time slice sets are complete. 3

4. Phase II (Climate Change) Results

5. Temperature and precipitation changes with model agreement
( minus ) A1B Scenario

6. Summer Temp Changes 2051-2070—1980-1999

7. Change in Winter Temperature Canadian Models
Global Model
Regional Model

8. Change in Winter Precip Canadian Models

9. HadRM3 Climate Change
Winter Temperature
Summer Temperature

10. There is a consistency in the anticipated temperature change signal of HadRM3PvsHadCM3
RCM
GCM
DJF
MAM
JJA
Projected seasonal changes in temperature, between and

11. HadRM3 Climate Change
Winter Precipitation
Summer Precipitation

12. Global Time Slice / RCM Comparison at same resolution (50km)
A2 Emissions Scenario
GFDL
AOGCM
NCAR
CCSM
Six RCMS
50 km
GFDL
AGCM
Time slice
50 km
CAM3
Time slice
50km
compare
compare

13. Future-current Summer Temperatures
GFDL CM2.1
GFDL AM2.1
Differences, 13

14. RegCM3 in GFDL Change in Summer Temperature

16. RegCM3 in GFDL Change in Winter Temperature

18. RegCM3 in GFDL % Change Precip - Winter

19. Why quantification of uncertainty is important
Because the uncertainties are not going away any time soon
Because we need to make decisions under conditions of uncertainty
Because many resource managers need this information (but doesn’t have to be probabilistic information – can be a range of scenarios)

20. Quantification of Uncertainty
The four GCM simulations already ‘situated’ probabilistically based on earlier work (Tebaldi et al., 2004)
RCM results nested in particular GCM would be represented by a probabilistic model (derived assuming probabilistic context of GCM simulation)
Use of performance metrics to differentially weight the various model results

21. Probabilistic Information on Climate Change for Colorado
For compared to current
Based on global model results from the IPCC archive (about 21 models)
Based on Tebaldi et al

22. Probability of temperature change for Colorado, Spring- A2 scenario
GFDL
HadCM3
CGCM
CCSM

23. Change in Temperature Spring
Canadian Global Model
Canadian Regional Model

24. Probability of Change in Precipitation – A2 Scenario
GFDL
HadCM
CCSM

25. Change in Precipitation in Spring (%)
Canadian global model
Canadian regional model

26. Spring Temperature Change 2041-2070 compared to 1971-2000
HadRM3 in HadCM3
CRCM in CGCM3
RegCM3 in GFDL

27. Change in Precipitation in Spring Regional Models
HadRM3 in HadCM3
RegCM3 in GFDL
CRCM in CGCM3

28. NARCCAP Project Timeline
Phase IIa
Current climate1
Future climate 1
Current and Future 2
Project Start
AOGCM Boundaries available
Phase 1
We are largely on track in terms of the time-line. Archiving of data takes up a lot of time. About 60 terabytes of data – a lot. Fifty-two variables are being saved. Won’t really finish second set of simulations until end of Planning users workshop for September 2009
12/07
5/09
9/07
1/06
9/08
11/09
Archiving Procedures - Implementation
Phase IIb
Time slices 28

29. Adaptation Planning for Water Resources
Develop adaptation plans for Colorado River water resources with stakeholders
Use NARCCAP scenarios, simple DS, statistical DS
Determine value of different types of higher resolution scenarios for adaptation plans
NCAR, USGS, B. Reclamation, and Western Water Initiative

30. End

31. Probability of temperature change for Colorado - A2 scenario
GFDL
CGCM
CCSM
HadCM3