Slideshow Transcript

1. Slide 1: TWO SOLITUDES how seasonality biases drought records from tree rings
2. Slide 12: TWO SOLITUDES how seasonality biases drought records from tree rings
3. Slide 14: why are Canadian streamflow reconstructions so lousy?
4. Slide 15: 100% 80% 60% explained variance 40% 20% 0% Canada USA
5. Slide 16: 100% Woodhouse et al., 2006 Meko et al., 2001 80% Sacramento River Upper Colorado River Meko et al., 2007 Colorado River Woodhouse, 2007 Middle Boulder Creek 60% explained variance 40% 20% 0% Canada USA
6. Slide 17: 100% Woodhouse et al., 2006 Meko et al., 2001 80% Sacramento River Upper Colorado River Meko et al., 2007 Colorado River Woodhouse, 2007 Middle Boulder Creek 60% Case and MacDonald, 2003 explained Saskatchewan River Beriault and Sauchyn, 2006 Churchill River variance Bonin and Burn, 2005 Athabasca River 40% Watson and Luckman, 2005 Gedalof et al., 2007 Bow River Columbia River 20% 0% Canada USA
7. Slide 18: why are Canadian tree rings not connected to climate modes?
8. Slide 19: Janice Lough and Hal Fritts The Southern Oscillation and tree rings: 1600 - 1961 Journal of Applied Meteorology 24, 1985 Roseanne D’Arrigo and Gordon Jacoby A thousand year record of northwestern New Mexico winter precipitation reconstructed from tree rings and its relation to El Niño and the Southern Oscillation The Holocene 1, 1991 David Stahle and collaborators Experimental dendroclimatic reconstruction of the Southern Oscillation Stahle et al., 1998 Bulletin of the American Meteorological Society 79, 1998
9. Slide 20: Prairie ringwidth records 138 Significant correlation with ENSO 4 Expected from random chance 6.9
10. Slide 24: seasonality
11. Slide 25: Trees, seasonality and climate forcings The southwestern US
12. Slide 26: Trees, seasonality and climate forcings The Canadian Prairies
13. Slide 28: DROUGHT AND SEASONALITY How does the connection between reconstructed drought 1 and seasonal precipitation vary across North America?
14. Slide 29: DROUGHT AND SEASONALITY How does the connection between reconstructed drought 1 and seasonal precipitation vary across North America? CLIMATE MODES AND TREE RINGS In which regions are drought reconstructions most strongly 2 connected to remote climate forcings (ENSO, PDO, AMO)?
15. Slide 30: The North American Drought Atlas Cook et al., 2007, Earth Science Reviews
16. Slide 31: Cook et al., 2007, Earth Science Reviews
17. Slide 32: CORRELATION COMPOSITES COHERENCE
18. Slide 33: PART ONE tree rings, drought and seasonality
19. Slide 35: significant (α=0.05)
20. Slide 36: instrumental tree rings
21. Slide 37: SUMM ER PRECIP ITAT ION
22. Slide 39: WINTER PRECIPITAT ION
23. Slide 41: do tree rings replicate these patterns?
24. Slide 44: +
25. Slide 45: summer mixed winter
26. Slide 46: DOMINANT not exclusive
27. Slide 47: “ ...the regional summer precipitation signal is strong in Pseudotsuga menziesii latewood-width [in southeastern Arizona]. David Meko and Chris Baisan Pilot study of latewood-width of conifers as an indicator of variability of summer rainfall in the North American monsoon region International Journal of Climatology 21, 2001
28. Slide 48: Medicine Hat, Alberta Source: Environment Canada, Adjusted Historical Canadian Climate Data, 1895 – 2006
29. Slide 49: Prairie ringwidth records 138 Significant correlation with ENSO 4 Expected from random chance 6.9 45
30. Slide 50: ENSO and winter precipitation
31. Slide 51: PART TWO drought records and climate modes
32. Slide 52: ENSO PDSI from tree rings PDO AMO
33. Slide 53: are these signals present in reconstructed drought?
34. Slide 54: Julia Cole and Ed Cook The changing relationship between ENSO variability and moisture balance in the continental United States Geophysical Research Letters 25, 1998
35. Slide 55: ENSO PDSI from tree rings PDO AMO
36. Slide 58: COMPOSITES where is it wet or dry when ENSO is strong?
37. Slide 61: ENSO PDSI from tree rings PDO AMO
38. Slide 64: LOW frequency
39. Slide 65: LOW FREQUENCIES (>7yr) TREE-RINGS and PDO 0.5 0.25 mean squared 61 0 coherence
40. Slide 66: LOW FREQUENCIES (>7yr) TREE-RINGS and PDO 0.5 0.25 mean squared 61 0 coherence
41. Slide 67: 3 Mexican PDSI 10 2 5 1 0 0 -1 -5 -2 -3 62 -10 1900 1920 1940 1960 1980 2000
42. Slide 68: 3 PDO index Mexican PDSI 10 2 5 1 0 0 -1 -5 -2 -3 63 -10 1900 1920 1940 1960 1980 2000
43. Slide 70: ENSO PDSI from tree rings PDO AMO
44. Slide 72: SEAS ONALITY AND D ROUGHT
45. Slide 73: summer mixed winter
46. Slide 74: IMPLICATIONS 1590s
47. Slide 75: IMPLICATIONS what/where OK
48. Slide 76: IMPLICATIONS what/where OK what/where/why NOT OK
49. Slide 77: IMPLICATIONS tree ring model output Celine Herwiejer, Richard Seager and Ed Cook North American droughts of the mid to late nineteenth century: a history, simulation and implication for Mediaeval drought The Holocene 16, 2006
50. Slide 78: summer mixed winter
51. Slide 79: M A N Y TH AN KS Dave Meko Ed Cook Hal Fritts Toby Ault