1. NARCCAP Users Meeting April 2011 Results from NCEP-driven RCMs Overview Based on Mearns et al. (BAMS, 2011) Results from NCEP-driven RCMs Overview Based on Mearns et al. (BAMS, 2011) William J. Gutowski, Jr. Iowa State University and The NARCCAP Team

2. NARCCAP Users Meeting April 2011 Simulations Analyzed Domain Domain - Most of North America Period Period - 1980-2004 Boundary Conditions Boundary Conditions - NCEP/DOE reanalysis Resolution Resolution - 50 km MM5 Iowa State/ PNNL RegCM3 UC Santa Cruz ICTP CRCMQuebec,Ouranos HADRM3 Hadley Centre RSMScrippsWRFNCAR/PNNL

3. NARCCAP Users Meeting April 2011 Analysis Regions Comparison with 0.5 o gridded observations from Univ. Delaware

4. NARCCAP Users Meeting April 2011 1. Means & Variability

5. NARCCAP Users Meeting April 2011 Temperature Bias - DJF Temp.BiasDJF -1010

6. NARCCAP Users Meeting April 2011 Temperature Bias Temp.BiasJJA -1010

7. NARCCAP Users Meeting April 2011 Interannual Variance 0.452.23

8. NARCCAP Users Meeting April 2011 Temperature Bias Interannual Variance 0.45 2.23

9. NARCCAP Users Meeting April 2011 Temperature Bias -60 60

10. NARCCAP Users Meeting April 2011 Temperature Bias -60 60

11. NARCCAP Users Meeting April 2011 Pattern Correlation

12. NARCCAP Users Meeting April 2011 Regional Annual Cycles -10 35 0 6 -10 35 - 5 0 8 0 0 6 6

13. NARCCAP Users Meeting April 2011 Regional Annual Cycles (bias) -10 35 0 6

14. NARCCAP Users Meeting April 2011 Temperature - Precipitation Correlations

15. NARCCAP Users Meeting April 2011 1982-83 El Nino 1997-98 El Nino multi-year drought Monthly time series of precipitation in coastal California small spread, high skill Substantial annual cycle

16. NARCCAP Users Meeting April 2011 Correlation with Observed Precipitation - Coastal California Model Correlation HadRM30.857 RegCM30.916 MM50.925 RSM0.945 CRCM0.946 WRF0.918 Ensemble 0.947 Ensemble mean has a higher correlation than any model All models have high correlations with observed monthly time series of precipitation.

17. NARCCAP Users Meeting April 2011 Monthly Time Series - Deep South Model Correlation HadRM30.489 RegCM30.231 MM50.343 RSM0.649 CRCM0.649 WRF0.513 Ensemble0.640 RSM+CRCM0.727 A “mini ensemble” of RSM and CRCM performs best in this region. Ensemble (black curve)

18. NARCCAP Users Meeting April 2011 2. Precipitation Extremes - Daily

19. NARCCAP Users Meeting April 2011 Region Analyzed Boreal forest Pacific coast California coast Great Lakes Maritimes Upper Mississippi River Deep South

20. NARCCAP Users Meeting April 2011 Precipitation Frequency vs. Intensity 99.5%

21. NARCCAP Users Meeting April 2011 99.5% Precipitation Frequency vs. Intensity NARCCAP - JJA

22. NARCCAP Users Meeting April 2011 Precipitation Frequency vs. Intensity NARCCAP - JJA (OBS = Co-op Stations)

23. NARCCAP Users Meeting April 2011 Precipitation Frequency vs. Intensity 99.5%

24. NARCCAP Users Meeting April 2011 Days with Simultaneous Extremes on “N” Grid Points

25. NARCCAP Users Meeting April 2011 Days with Simultaneous Extremes on “N” Grid Points

26. NARCCAP Users Meeting April 2011 Composite Structure of Extreme Events - DJF NARR m/s

27. NARCCAP Users Meeting April 2011 Composite Structure of Extreme Events - DJF NARR MM5 GFDL CCSM + 9 hr NARCCAP

28. NARCCAP Users Meeting April 2011 Composite Structure of Extreme Events - DJF MM5 GFDL CCSM NARR 2-m specific humidity anomaly

29. NARCCAP Users Meeting April 2011 Composite Structure of Extreme Events - DJFNARCCAP NARR GFDL HadRM3 CCSM + 9 hr 2-m specific humidity anomaly

30. NARCCAP Users Meeting April 2011 Thank You! (www.narccap.ucar.edu)

31. NARCCAP Users Meeting April 2011  Higher resolution is necessary, but not sufficient, for simulating short-term (e.g., daily) precipitation extremes.  Coarser models (and nudged regional models) tend to have daily extremes covering a wider area than observed extremes.  Focusing on environments conducive to extremes yields relevant climatic behavior, even in relatively coarse models.  This conclusion rests on the assumption that important small-scale features are not missing (e.g., low-level jets).

32. NARCCAP Users Meeting April 2011 Part I: Interannual Variability Results shown for 1981-2002 Results shown for 1981-2002 Comparison with 0.5 o gridded precipitation analysis from the University of Delaware Comparison with 0.5 o gridded precipitation analysis from the University of Delaware

33. NARCCAP Users Meeting April 2011 Precipitation analysis for two regions Coastal California Deep South

34. NARCCAP Users Meeting April 2011 Monthly Time Series - Deep South Model Correlation HadRM30.489 RegCM30.231 MM50.343 RSM0.649 CRCM0.649 WRF0.513 Ensemble0.640 Two models (RSM and CRCM) perform much better. These models inform the domain interior about the large scale. Ensemble (black curve)

35. NARCCAP Users Meeting April 2011 Full ensemble RSM + Canadian RCM The "mini-ensemble" has better correlation than the full ensemble in the southern and eastern parts of the domain. Other measures of forecast skill (such as bias) are not necessarily better. Correlation of Monthly Time Series

36. NARCCAP Users Meeting April 2011 Ensemble error and spread (January) Bias Ensemble spread There are hints of a spread-skill relation but it is not consistent.

37. NARCCAP Users Meeting April 2011 ensemble July minus June observed July minus June The ensemble reproduces the dipole of June- July precipitation change, but the monsoon does not extend as far north as observed.

38. NARCCAP Users Meeting April 2011 Part 2: Extreme Monthly Precipitation Observations Observations  Precip: University of Washington VIC retrospective analysis  500 hPa Heights: North American Regional Reanalysis Comparison period: 1982 -1999 Comparison period: 1982 -1999  1979-1981 omitted - spinup  UW data end in mid-2000 Analysis Analysis  Cold season (Oct-Mar)  10 wettest months (top 10%)

39. NARCCAP Users Meeting April 2011 Regions Analyzed Boreal forest Pacific coast California coast Deep South Great Lakes Maritimes Upper Mississippi River

40. NARCCAP Users Meeting April 2011 Frequency – Coastal CA

41. NARCCAP Users Meeting April 2011 Ranked Precipitation – Coastal CA Ensemble average of top 10 = 9 % smaller than UW

42. NARCCAP Users Meeting April 2011 Interannual Variability – Coastal CA 59 of 60 (98%) simulated extremes occur in cold seasons with an observed extreme. (random chance: 27)

43. NARCCAP Users Meeting April 2011 Composite 500 hPa Height Anomalies Top 10 Extremes Coastal CA

44. NARCCAP Users Meeting April 2011 Frequency – Deep South

45. NARCCAP Users Meeting April 2011 Ranked Precipitation – Deep South Ensemble average of top 10 = 22 % smaller than UW

46. NARCCAP Users Meeting April 2011 Interannual Variability – Deep South 27 of 60 (45%) simulated extremes occur in cold seasons with an observed extreme. (random chance: 27)

47. NARCCAP Users Meeting April 2011 500 hPa Height Anomalies – Deep South Extreme

48. NARCCAP Users Meeting April 2011 Summary Monthly Precipitation Where there is a substantial periodic cycle: - Models simulate well the interannual variability - Models simulate well monthly, regional extremes Where there is no substantial periodic cycle: - Models simulate poorly the interannual var. & extremes - Interior nudging improves interannual variability - Interior nudging does not help extremes

49. NARCCAP Users Meeting April 2011 Hydrologic Analysis (Takle et al.) SWAT model domain Simulation period: last 2 decades of 20C

50. NARCCAP Users Meeting April 2011 Hydrologic Analysis (Takle et al.) Streamflow Interannual Variability

51. NARCCAP Users Meeting April 2011 Hydrologic Analysis (Takle et al.) Precipitation Annual Cycle

52. NARCCAP Users Meeting April 2011 Hydrologic Analysis (Takle et al.) Streamflow Annual Cycle

53. NARCCAP Users Meeting April 2011 Summary MONTHLY PRECIPITATION Where there is a substantial periodic cycle: - Models simulate well the interannual variability - Models simulate well monthly, regional extremes Where there is no substantial periodic cycle: - Models simulate poorly the interannual var. & extremes - Interior nudging improves interannual variability -Interior nudging does not help extremes UPPER MISSISSIPPI STREAMFLOW Ensemble replicates well the interannual variability Annual cycle simulated less well

54. NARCCAP Users Meeting April 2011 2b. Precipitation Extremes - Monthly

55. NARCCAP Users Meeting April 2011 Ranked Precipitation – Coastal CA Ensemble average of top 10 = 9 % smaller than UW

56. NARCCAP Users Meeting April 2011 Ranked Precipitation – Upper MS Ensemble average of top 10 = 6 % smaller than UW

57. NARCCAP Users Meeting April 2011 Ranked Precipitation – Deep South Ensemble average of top 10 = 22 % smaller than UW

58. NARCCAP Users Meeting April 2011 Regional Annual Cycles -10 35 0 6

59. NARCCAP Users Meeting April 2011 Temperature Bias Interannual Variance 0.45 2.23

60. NARCCAP Users Meeting April 2011 Composite Structure of Extreme Events - DJF

61. NARCCAP Users Meeting April 2011 Composite Structure of Extreme Events - DJF

62. NARCCAP Users Meeting April 2011 Composite Structure of Extreme Events - DJF