1. Climate Change Modeling Can you get what you want? October 28, 2009 Elissa Lynn Senior Meteorologist, CA Dept. Water Resources elynn@water.ca.gov

2. Climate Change Modeling Can you get what you want? you October 28, 2009 Elissa Lynn Senior Meteorologist, CA Dept. Water Resources elynn@water.ca.gov

4. 17 year TV Meteorologist

5. Emmy Award, Literacy Awards

6. Teacher/ College Instructor

8. 10 Warmest Years on Earth Seven of eight warmest years have occurred since 2001 2005 1998 2002 2003 2007 2006 2004 2001 1997 2008 (Since 1880, source National Climate Data Center)

9. Temperature Trends Globally: 10 warmest years since 1997 128 year record; Climatic Data Center

10. Temperature Trends United States: 6 of 10 warmest since 1998 Source: NASA, NCDC, AMS

11. Temperature Trends California: 1934 still hottest Source: CA State Climatologist

12. Climate Change vs.Global Warming

13. Climate Change vs.Global Warming NOT just hotter

14. Climate Change vs.Global Warming NOT just hotter Precipitation; More-Less Different spatial distribution of Rain Changing Snow Levels Sea-level Rise Air Quality Atmosphere/Ocean Circulation

17. Why so complicated? Data collection Computer model variability Feedback mechanisms? Spatial Resolution

18. Daisy World

19. Daisy World

20. Daisy World

21. MODELING stuff Math Equations = Parameterization PHYSICS not terribly hard

22. MODELING stuff Some processes poorly understood, handled Especially CLOUDS

23. MODELING stuff Can’t model things we don’t understand Feedback Mechanisms

24. MODELING stuff Long-range trends, Larger-scale answers Resolution Too Coarse

25. California in a Global Climate Model

26. MODELING stuff Models have Bias You need to quantify UNCERTAINTY

27. MODELING stuff Real World responding faster! How to make DECISIONS?

28. Observed Impactsin California 1o F Increase/ 100 yrs

29. Observed Impactsin California 1o F Increase/ 100 yrs Warmer at night Warmer in winter

30. CA temps 1900-1950 vs. 1950-2000 Highs p0.6o F Average p0.9o F Lows p1.4o F

31. CA Mean Temperatures oF Source: Western Region Climate Center

32. Observed Impactsin California 1o F Increase/ 100 yrs Warmer at night Warmer in winter 7” sea level rise

33. Sea Level at Golden Gate Sea Level Rise at Golden Gate Bridge

35. Melting of polar ice caps, glaciers

39. Observed Impactsin California 1o F Increase/ 100 yrs Warmer at night Warmer in winter 7” sea level rise Earlier Snowmelt Snowpack Loss: 10% already

40. Snowpack Reduction Source: Scripps Institute of Oceanography

41. Observed Impactsin California 1o F Increase/ 100 yrs Warmer at night Warmer in winter 7” sea level rise Earlier Snowmelt Snowpack Loss: 10% already Increasing River Peak Flows

42. Peak 3-day River Flows

43. More as Rain_ bigger flood New Historical

44. What about Me?

45. What about Me? Climate models do not SCALE well Regional Impacts vary Can they give local information?

46. ? Global Climate Simulation Model ? Hydrologic Models ? CO2 Emissions Scenario ? Operations Models Global-to-Local “Climate Downscaling” ? Adapted from Cayan and Knowles, SCRIPPS/USGS, 2003 We’ve got Issues!

47. Downscaling Converting Global model output into Regional or Local information More specific, Higher resolution, More useful Courtesy Jamie Anderson, DWR SWP= State Water Project CVP=Central Valley Project

48. Images from Mike Dettinger, USGS

49. Downscaling Methods Dynamical Statistical Empirical

50. Who’s Doing What? What data is available? Figure: Maurer (Santa Clara), Hidalgo (Scripps) Downscaling

52. Work / Resources being committed

53. Some data already available

54. Several years away from detail, but enough information for you to plan EARLY

55. Thank Yous Dr. Michael Anderson, DWR State Climatologist John Andrew, DWR Asst. Deputy Dir, Climate Change Jamie Anderson DWR, Bay-Delta Office Mike Dettinger, USGS - Scripps Phil Duffy, Climatecentral.org Ed Maurer, Santa Clara Univ. Hugo Hidalgo/Dan Cayan, Scripps Levi Brekke, USBR