White cedar 1452Source: Danny Margoles
Bur oak >450 yrSource: Joe Zeleznik NDSU
Climate history of North America                        Younger              Demise of Laurentide                         ...
DECADALCLIMATE VARIABILITY
“   ‘Drought’ people get. ‘Decadal-scale climate variability’    gets me that glazed eye look.                            ...
Behold, there comes seven years of great plenty throughoutall the land of Egypt: And there shall arise a er them sevenyear...
“   We shall speak of “Joseph-wild” behavior when the we est decade    within a century includes an extraordinary “term” o...
Pacific Decadal Oscillation index3210-1-2-3     1900   1920     1940      1960      1980   2000
Atlantic Multidecadal Oscillation index
“   An improved understanding of [Decadal Climate Variability] is very important because    stakeholders and policymakers ...
Observations             Models               Proxies
THE DECADAL BLIND SPOT
MINNESOTA   THE DECADAL BLIND SPOT  OBSERVATIONS
Source: Franklin Hunting
The Atlantic Multidecadal Oscillation and its relationto rainfall and river flows in the continental U.S.David B. Enfield, A...
Does the state of the PDO and AMO influence the frequency of drought?                                                      ...
“   The decadal time scale offers    a critical bridge for informing    adaptation strategies as                           ...
OCEAN
LAND
Toby Ault National Corporation for Atmospheric Research
Is precipitation every red?
Using singular spectral analysis       to decompose precipitation recordsAult and St. George, Journal of Climate, 2010
GEOGRAPHYMATTERS A LOT
Decadal ‘hotspots’ in winter precipitation                                                0%   10%   20%   30% varianceAul...
Central Pacific Coast
Ault and St. George, Journal of Climate, 2010
Ault and St. George, Journal of Climate, 2010
NOT  LOCALLY        FIELDSIGNIFICANT   SIGNIFICANT
Carlo Emilio Bonferroni        1892 - 1960
Decadal ‘hotspots’ in winter precipitation                                                0%   10%   20%   30% varianceAul...
“   ... the use of high-resolution paleoclimate proxy data should be    expanded because the short observational record an...
MINNESOTA  THE DECADAL BLIND SPOT   PROXIES
“ RINGS    IN THE BRANCHES OF    SAWED TREES SHOWTHE NUMBER OF YEARS  AND, ACCORDING TO THEIR     THICKNESS,   THE YEARS W...
Tree-ring display at elementary school                                    Photograph:Tom Swetnam
water stressnarrow ring     reduced photosynthesis                  less cell expansion                 reduced cell divis...
Central Pacific Coast
Source: Dan Griffin
St. George and Ault, Journal of Geophysical Research - Atmospheres, 2011
really                                                                           decadalSt. George and Ault, Journal of Ge...
really                                                                           not that                                 ...
7 track this signal23 don’t
“ THERMOMETERS ” TREES ARE NOT OR RAIN GAUGES.    Keith Briffa and colleagues
White pine 1714Source: Kurt Kipfmueller
∆S
Vit Klemeš 1932 - 2010
“   Discharge or lake records ‘‘have a tendency to    exhibit more pronounced and smoother cycles’’    than precipitation ...
Do proxiesPUMP UP low-frequency signals?
Source: Stella Cousins
Source: Jansen Cardy     Sarah Truebe University of Arizona
Source: Sarah Truebe, University of Arizona
Truebe et al., IOP Conference Series : Earth and Environmental Science, 2010
“   ...variability in this range [less than 100 years]    can represent a mixed signal of climate input    and subsurface ...
Observations             Models               Proxies
MINNESOTA  THE DECADAL BLIND SPOT   MODELS
“   Although global coupled models designed in the last 15 years    are able to generate DCV pa erns that resemble observe...
Toby Ault National Corporation for Atmospheric Research
The power-law scaling parameter            β relates variance to timescale.
The spectrum of SST observations is either ‘red’ or ‘white’                                             Beta value of SST
The spectrum of simulated SST is too ‘white’ or too ‘blue’                                             Beta value of SST
Because the interannual components are too energetic,is it possible they might be forcing decadal components in unrealisti...
THE DECADAL BLIND SPOT
Observations             Models               Proxies
1We need to test the ability of models tosimulate terrestrial climates at decadal timescales.
2We need to use (or develop) physically-basedforward models to test how proxies record(and possibly distort) low-frequency...
“   The decadal time scale offers    a critical bridge for informing    adaptation strategies as                           ...
The decadal blind spot - understanding low-frequency behavior in the climate system
The decadal blind spot - understanding low-frequency behavior in the climate system
The decadal blind spot - understanding low-frequency behavior in the climate system
The decadal blind spot - understanding low-frequency behavior in the climate system
The decadal blind spot - understanding low-frequency behavior in the climate system
The decadal blind spot - understanding low-frequency behavior in the climate system
The decadal blind spot - understanding low-frequency behavior in the climate system
The decadal blind spot - understanding low-frequency behavior in the climate system
The decadal blind spot - understanding low-frequency behavior in the climate system
The decadal blind spot - understanding low-frequency behavior in the climate system
The decadal blind spot - understanding low-frequency behavior in the climate system
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The decadal blind spot - understanding low-frequency behavior in the climate system

  1. 1. White cedar 1452Source: Danny Margoles
  2. 2. Bur oak >450 yrSource: Joe Zeleznik NDSU
  3. 3. Climate history of North America Younger Demise of Laurentide Dryas Ice Sheet 20 16 12 8 4 0 THOUSANDS OF YEARS AGO Final Drainage of Lake AgassizLAST GLACIAL MODERN MAXIMUM OBSERVATIONS
  4. 4. DECADALCLIMATE VARIABILITY
  5. 5. “ ‘Drought’ people get. ‘Decadal-scale climate variability’ gets me that glazed eye look. John Fleck Albuquerque Journal ”
  6. 6. Behold, there comes seven years of great plenty throughoutall the land of Egypt: And there shall arise a er them sevenyears of famine; and all the plenty shall be forgo en in theland of Egypt; and the famine shall consume the land; Genesis 41, 29-30
  7. 7. “ We shall speak of “Joseph-wild” behavior when the we est decade within a century includes an extraordinary “term” of wet years. ”
  8. 8. Pacific Decadal Oscillation index3210-1-2-3 1900 1920 1940 1960 1980 2000
  9. 9. Atlantic Multidecadal Oscillation index
  10. 10. “ An improved understanding of [Decadal Climate Variability] is very important because stakeholders and policymakers want to know the likely climate trajectory for the coming decades for applications to water resources, agriculture, energy, and infrastructure development. ”
  11. 11. Observations Models Proxies
  12. 12. THE DECADAL BLIND SPOT
  13. 13. MINNESOTA THE DECADAL BLIND SPOT OBSERVATIONS
  14. 14. Source: Franklin Hunting
  15. 15. The Atlantic Multidecadal Oscillation and its relationto rainfall and river flows in the continental U.S.David B. Enfield, Alberto M. Mestas‐Nuñez and Paul J. TrimbleGeophysical Research Le ers, 2001
  16. 16. Does the state of the PDO and AMO influence the frequency of drought? AMOnegative AMOpositive PDOpositive PDOnegativeMcCabe et al, Proceedings of the National Academy of Sciences, 2004
  17. 17. “ The decadal time scale offers a critical bridge for informing adaptation strategies as ” climate varies and changes. Meehl et al., BAMS, 2009
  18. 18. OCEAN
  19. 19. LAND
  20. 20. Toby Ault National Corporation for Atmospheric Research
  21. 21. Is precipitation every red?
  22. 22. Using singular spectral analysis to decompose precipitation recordsAult and St. George, Journal of Climate, 2010
  23. 23. GEOGRAPHYMATTERS A LOT
  24. 24. Decadal ‘hotspots’ in winter precipitation 0% 10% 20% 30% varianceAult and St. George, Journal of Climate, 2010
  25. 25. Central Pacific Coast
  26. 26. Ault and St. George, Journal of Climate, 2010
  27. 27. Ault and St. George, Journal of Climate, 2010
  28. 28. NOT LOCALLY FIELDSIGNIFICANT SIGNIFICANT
  29. 29. Carlo Emilio Bonferroni 1892 - 1960
  30. 30. Decadal ‘hotspots’ in winter precipitation 0% 10% 20% 30% varianceAult and St. George, Journal of Climate, 2010
  31. 31. “ ... the use of high-resolution paleoclimate proxy data should be expanded because the short observational record and model uncertainty are unable to simulate [Decadal Climate Variability]... ” Mehta et al. Bulletin of the American Meteorological Society 2011
  32. 32. MINNESOTA THE DECADAL BLIND SPOT PROXIES
  33. 33. “ RINGS IN THE BRANCHES OF SAWED TREES SHOWTHE NUMBER OF YEARS AND, ACCORDING TO THEIR THICKNESS, THE YEARS WHICH WERE MORE OR LESS DRY.” Leonardo da Vinci
  34. 34. Tree-ring display at elementary school Photograph:Tom Swetnam
  35. 35. water stressnarrow ring reduced photosynthesis less cell expansion reduced cell division
  36. 36. Central Pacific Coast
  37. 37. Source: Dan Griffin
  38. 38. St. George and Ault, Journal of Geophysical Research - Atmospheres, 2011
  39. 39. really decadalSt. George and Ault, Journal of Geophysical Research - Atmospheres, 2011
  40. 40. really not that decadal decadalSt. George and Ault, Journal of Geophysical Research - Atmospheres, 2011
  41. 41. 7 track this signal23 don’t
  42. 42. “ THERMOMETERS ” TREES ARE NOT OR RAIN GAUGES. Keith Briffa and colleagues
  43. 43. White pine 1714Source: Kurt Kipfmueller
  44. 44. ∆S
  45. 45. Vit Klemeš 1932 - 2010
  46. 46. “ Discharge or lake records ‘‘have a tendency to exhibit more pronounced and smoother cycles’’ than precipitation because of storage. ” Vit Klemeš
  47. 47. Do proxiesPUMP UP low-frequency signals?
  48. 48. Source: Stella Cousins
  49. 49. Source: Jansen Cardy Sarah Truebe University of Arizona
  50. 50. Source: Sarah Truebe, University of Arizona
  51. 51. Truebe et al., IOP Conference Series : Earth and Environmental Science, 2010
  52. 52. “ ...variability in this range [less than 100 years] can represent a mixed signal of climate input and subsurface storage. ” Truebe et al. IOP Conference Series : Earth and Environmental Science, 2010
  53. 53. Observations Models Proxies
  54. 54. MINNESOTA THE DECADAL BLIND SPOT MODELS
  55. 55. “ Although global coupled models designed in the last 15 years are able to generate DCV pa erns that resemble observed DCV pa erns, the models tend to displace them spatially ” and temporally with respect to observed pa erns. Mehta et al. Bulletin of the American Meteorological Society 2011
  56. 56. Toby Ault National Corporation for Atmospheric Research
  57. 57. The power-law scaling parameter β relates variance to timescale.
  58. 58. The spectrum of SST observations is either ‘red’ or ‘white’ Beta value of SST
  59. 59. The spectrum of simulated SST is too ‘white’ or too ‘blue’ Beta value of SST
  60. 60. Because the interannual components are too energetic,is it possible they might be forcing decadal components in unrealistic ways?
  61. 61. THE DECADAL BLIND SPOT
  62. 62. Observations Models Proxies
  63. 63. 1We need to test the ability of models tosimulate terrestrial climates at decadal timescales.
  64. 64. 2We need to use (or develop) physically-basedforward models to test how proxies record(and possibly distort) low-frequency climate signals.
  65. 65. “ The decadal time scale offers a critical bridge for informing adaptation strategies as ” climate varies and changes. Meehl et al., BAMS, 2009

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