Slideshow Transcript

1. Slide 1: The prominence of decadal variability in North American precipitation S c ott St. G eorge Geological Survey of Canada Toby A ult University of Arizona
2. Slide 3: Greg McCabe, Michael Palecki, and Julio Betancourt, 2004: Pacific and Atlantic Ocean influences on multidecadal drought frequency in the United States PNAS 12, 4136 - 4141
3. Slide 4: Here be decadal variability Decadal variability in precipitation or drought as a signal detection problem Terrestrial climate records often processed to emphasize D2M timescales4
4. Slide 5: Does it matter at the regional scale? 5
5. Slide 6: 1920 1940 1960 1980 2000 Decadal variance 30% Decadal variance 5% 1920 1940 1960 1980 2000
6. Slide 7: Where is decadal variability in precipitation strong?
7. Slide 8: Dan Cayan, Michael Dettinger, Henry Diaz, and Nick Graham,1998: Decadal variability of precipitation over western North America. Journal of Climate 11, 3148-3166
8. Slide 9: Methods Photo: Christos_m2001
9. Slide 10: PDSI Temperature Precipitation Streamflow Storms Rain/snow
10. Slide 11: Gridded (0.5 deg) monthly precipitation, Climate Research Unit, University of East Anglia Period of record: 1901 - 2002
11. Slide 12: Decadal variability Decadal variabil Decadal varia Decadal v
12. Slide 15: Noise Interannual Trend Multidecadal Decadal
13. Slide 17: What did we find? Photo: futureshape
14. Slide 18: Slides missing* * Thank goodness
15. Slide 19: Winter decadal 0% 10% 20% 30% variance
16. Slide 20: Autumn decadal 0% 10% 20% 30% variance
17. Slide 21: Annual multidecadal 0% 10% 20% 30% variance
18. Slide 22: Northern California precipitation
19. Slide 23: Northern California precipitation Decadal variance = ~30 percent
20. Slide 24: D2M ‘hotspots’
21. Slide 25: “Decadal-scale fluctuations are crucial because they control water supplies, affect biota, and may modulate higher-frequency events such as floods and drought.” Dan Cayan and colleagues [1998]
22. Slide 26: Decadal hotspot - Oregon/California
23. Slide 27: Northern California
24. Slide 28: Sacramento River Photo: Patty Colmer
25. Slide 29: Northern California
26. Slide 30: Northern California
27. Slide 31: Photo: California Department of Water Resources Levee break, Sacramento basin
28. Slide 32: 1915 levee break Photo: California Department of Public Works Courtesy Joan Florsheim
29. Slide 33: Northern California
30. Slide 34: Northern California
31. Slide 35: Decadal hotspot - Minnesota
32. Slide 36: Minnesota
33. Slide 37: Mississippi River at Minneapolis Photo: Mulad
34. Slide 38: Minnesota
35. Slide 39: Minnesota
36. Slide 40: Minnesota
37. Slide 41: Mech et al. (1987): Does high snow over consecutive winters have a cumulative, negative, effect on the viability of moose offspring?
38. Slide 42: Minnesota
39. Slide 43: Minnesota
40. Slide 44: Minnesota
41. Slide 45: Associations with major climate modes
42. Slide 46: It’s complicated. 46
43. Slide 47: Winter precipitation and the PDO
44. Slide 48: Winter precipitation and the PDO
45. Slide 49: Three main points 49
46. Slide 50: location and seasonality make a big difference 50
47. Slide 51: D2M propagates into hydrology* and ecology** * clearly ** maybe 51
48. Slide 52: Is it a coincidence that D2M variability is strongest in the ENSO-PDO null? 52
49. Slide 53: Thank you Julio Betancourt Dave Meko Julia Cole Joellen Russell Susan Pullan Mike Wallace Mike Mann Connie Woodhouse Support Manitoba Hydro Natural Resources Canada National Science Foundation
50. Slide 54: S co t t St. G e o r g e Toby Au lt Geological Survey of Canada University of Arizona sstgeorg@nrcan.gc.ca tault@email.arizona.edu