Extreme Daily Precipitation in Global and Regional Climate Simulations of North America

1. Extreme Daily Precipitation in Global and Regional Climate Simulations of North America William J. Gutowski, Jr. Sho Kawazoe Iowa State University, Ames, IA

2. NARCCAP Simulations WRF NCAR/ PNNL MM5 Iowa State/ PNNL RegCM3 UC Santa Cruz ICTP CRCM Quebec, Ouranos HADRM3 Hadley Centre RSM Scripps • Domain - Most of North America • Resolution ~ 50 km • Simulation Period - 1978-2004 • Boundary Conditions - NCEP/DOE reanalysis PLUS: GFDL Atmosphere GCM - 0.5˚ resolution - specified SST/ice for same period NCAR CCSM Atmosphere-Ocean GCM (CMIP3) - 1.4˚ (T85) resolution - analysis for same period

3. CMIP5 20C GCM Simulations

4. Comparison with observations • Observation-based Fields • Precip: University of Washington VIC retrospective analysis • Other fields: North American Regional Reanalysis • Comparison period: 1982 -1999 • 1979-1981 omitted for RCM spinup • UW data end in mid-2000 • Analysis • “Precipitation event” = Daily precip ≥ 2.5 mm at a grid point • Focus on precip intensity ≥ 99.5% • Pool all “events” in the target region

5. Region Analyzed Boreal forest Maritimes Great Lakes Pacific coast Upper Mississippi River Deep South California coast

6. Precipitation Frequency vs. Intensity NARCCAP - DJF 99.5%

7. Precipitation Frequency vs. Intensity CMIP5 - DJF 99.5%

8. Precipitation Frequency vs. Intensity NARCCAP - JJA 99.5%

9. Precipitation Frequency vs. Intensity NARCCAP - JJA (OBS = Co-op Stations)

10. Precipitation Frequency vs. Intensity CMIP5 - JJA 99.5%

11. Composite Structure of Extreme Events - JJA m/s NARR 10-m Wind

12. Composite Structure of Extreme Events - JJA NARCCAP NARR RegCM GFDL CCSM + 9 hr 10-m Wind

13. Composite Structure of Extreme Events - JJA CMIP5 NARR HadGEM - 1.25˚ X 1.875˚ CanESM - 2.8˚ X 2.8˚ 10-m Wind

14. Composite Structure of Extreme Events - JJA NARR 2-m specific humidity anomaly

15. Composite Structure of Extreme Events - JJA NARCCAP NARR WRF GFDL CCSM + 9 hr 2-m specific humidity anomaly

16. Composite Structure of Extreme Events - DJF CMIP5 NARR HadGEM - 1.25˚ X 1.875˚ NorESM – 1.9˚ X 2.5˚ CanESM – 2.8˚ X 2.8˚

17. SUMMARY • Higher resolution is necessary, but not sufficient, for simulating daily precipitation extremes. • Coarser models (and nudged regional models) tend to have daily extremes covering a wider area than observed extremes. • Models over a range of resolutions simulating processes giving extremes • Do well in DJF (synoptic weather) • Need finer resolution in JJA (convective processes)

18. Thank You

19. Extra Slides

20. Composite Structure of Extreme Events - JJA UW obs Precipitation [mm/d]

21. Composite Structure of Extreme Events - JJA NARCCAP UW obs CRCM GFDL CCSM Precipitation [mm/d]

22. Composite Structure of Extreme Events - JJA CMIP5 UW obs CRCM HadGEM - 1.25˚ X 1.875˚ GFDL NorESM – 1.9˚ X 2.5˚ CCSM CanESM – 2.8˚ X 2.8˚ Precipitation [mm/d]

23. Composite Structure of Extreme Events - DJF m/s NARR

24. Composite Structure of Extreme Events - DJF NARCCAP NARR MM5 GFDL CCSM + 9 hr

25. Composite Structure of Extreme Events - DJF CMIP5 NARR HadGEM - 1.25˚ X 1.875˚ CanESM - 2.8˚ X 2.8˚

26. Composite Structure of Extreme Events - DJF MM5 GFDL NARR CCSM 2-m specific humidity anomaly

27. Composite Structure of Extreme Events - DJF NARCCAP NARR HadRM3 GFDL CCSM + 9 hr 2-m specific humidity anomaly

28. Composite Structure of Extreme Events - DJF CMIP5 NARR HadGEM - 1.25˚ X 1.875˚ NorESM – 1.9˚ X 2.5˚ CanESM – 2.8˚ X 2.8˚

29. Days with Simultaneous Extremes on “N” Grid Points “widespread extremes”

30. Composite Structure of Extreme Events - DJF

31. Composite Structure of Extreme Events - DJF

32. Composite Structure of Extreme Events - DJF

33. Composite Structure of Extreme Events - JJA

34. Composite Structure of Extreme Events - JJA

35. Composite Structure of Extreme Events - JJA

36. Days with Simultaneous Extremes on “N” Grid Points “widespread extremes”

37. Days with Simultaneous Extremes on “N” Grid Points