Contemporary problems in ancient climates

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Contemporary problems in ancient climates

  1. 1. CONTEMPORARY ISSUES IN THE STUDY OF ANCIENT CLIMATESCLIMATE SCIENCE, STATISTICS AND THE COMPUTATIONAL SCIENCES READING GROUP APRIL 2012
  2. 2. anecdote
  3. 3. “ It doesnt really seem like winter. It seems more like an unusual fall that kind of lingers on and doesnt go anywhere. ” Jessica Forster Commenting on the mild 2012 winter in Minnesota
  4. 4. observation
  5. 5. Weather data recorded by the Department of Earth Sciences h p://sokar.geo.umn.edu/weather/
  6. 6. The Central England Temperature record is the longest instrumental record of temperature in the world. Degrees celsius relative to the long-term meanSource: Parker et al., Journal of Climate, 1992
  7. 7. Source: Goddard Institute for Space Studies, NASA
  8. 8. The number of climate stations recording air temperature falls off rapidly prior to AD 1900. Number of stations in the Northern HemisphereSource: Jones et al., Journal of Geophysical Research, 2012
  9. 9. anecdote < observations <<
  10. 10. ‘Striations’ (scratches) on bedrock near Knife Lake, BWCAWSource: Blue~Canoe
  11. 11. Thickness of glacial ice 3000 m IDS Tower 241 m
  12. 12. 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
  13. 13. CLIMATE PROXIES ice cores tree rings lake sediments speleothems corals
  14. 14. CLIMATE “PROXIES” natural phenomena which are climate-dependent, and which incorporate into their structure a measure of this dependency.Source: Bradley, Paleoclimatology: Reconstructing climates of the Quaternary, 1995
  15. 15. Source: Tim Shanahan, University of Texas at Austin
  16. 16. Source: Geological Survey of Canada
  17. 17. Source: LACCORE, University of Minnesota
  18. 18. Source: Stella Cousins
  19. 19. “ To anticipate future changes, we must understand how and why climates varied in the past. Dr. Ray Bradley University of Massachuse s ”
  20. 20. PALEOCLIMATOLOGYthe study of climate prior to the period of instrumental measurement
  21. 21. Global networks of climate proxies have been used to estimate past changes in hemispheric temperature.Source: Commi ee on Surface Temperature Reconstructions for the Last 2,000 Years, National Research Council, 2006
  22. 22. How did the ENSO system behave prior to the 20th century?
  23. 23. Tree-ring estimates of 1,200 years of Colorado River discharge Meko et al., GRL, 2007
  24. 24. OBSERVATIONS PROXIES MODELS
  25. 25. “ Each individual proxy provides a record of environmental change, but the process of combining these signals into a spatially averaged temperature signal requires careful statistical evaluation. Commi ee on Surface Temperature Reconstructions for the Last 2,000 Years ” National Research Council
  26. 26. ? How can we extract climatic signals froma large, diverse network of noisy proxies thatare distributed irregularly around the planet?
  27. 27. Tree-ring display at elementary schoolSource: Tom Swetnam
  28. 28. Intermountain bristlecone pine 4,844 yearsSource: Tom Harlan
  29. 29. Giant sequoia 3,266 yearsSource: Julie Jordan Sco
  30. 30. Eastern white cedar (in Minnesota) 560 yearsSource: Danny Margoles
  31. 31. Pinus spp.Source: Paul Schulte
  32. 32. Source: Baillie (1982)
  33. 33. 755 m3/s847 m 3/s809 m 3/s770 m 3/s823 m 3/s787 m 3/s901 m3/s 3
  34. 34. TEMPERATUREhigh growth frozen water low photosynthetic rate low photosynthetic rate higher evaporation shorter growing seasonlow growth cold hot
  35. 35. WATERhigh growth reduced cell division flooding reduced cell expansion anoxic conditions C02 starvationlow growth dry wet
  36. 36. Single-site reconstruction
  37. 37. rain gauges tree ringsSource: Hughes and Funkhouser, 1998
  38. 38. “ THERMOMETERS ” TREES ARE NOT OR RAIN GAUGES. Keith Briffa and colleagues
  39. 39. 3CHALLENGESIN DENDROCLIMATOLOGY
  40. 40. 3 Do climate-sensitive trees (and other proxies) transform climate signals in predictable ways?
  41. 41. 2 Is there an optimal approach for recovering low-frequency variability from climate-sensitive tree rings?
  42. 42. 1Should paleoclimatic estimates from trees be derivedfrom (a) common pa erns or (b) optimal predictors?
  43. 43. Source: Baillie (1982)
  44. 44. Network reconstruction
  45. 45. “ Continental- and hemispheric-scale networks contain robust synoptic-scale pa erns, which may o en be interpreted in terms of climatic conditions. Dr. Malcolm Hughes ” University of ArizonaSource: Hughes, Dendroclimatology, 2010
  46. 46. Tree-ring records in North America circa 1990Source: Meko et al., Journal of Climate, 1991
  47. 47. Major regional pa erns recovered from North American tree ringsSource: Meko et al., Journal of Climate, 1991
  48. 48. Tree-ring data used to estimate past drought in North America Cook et al., Journal of Quaternary Sciences, 2010
  49. 49. One thousand years of drought in western North America Cook et al., Science, 2004
  50. 50. alternative
  51. 51. ‘Optimal’ reconstruction
  52. 52. PACIFICDECADALOSCILLATION
  53. 53. Pacific Decadal Oscillation index3210-1-2-3 1900 1920 1940 1960 1980 2000
  54. 54. Are these two records more closely tuned to the North Pacific Ocean than other tree-ring data from North America?Source: MacDonald and Case, Geophysical Research Le ers, 2005
  55. 55. “ This method of selecting proxies by screening a potentially large number of candidates for positive correlations runs the danger of choosing a proxy by chance. Gerg Bürger Freie Universität-Berlin ”Source: Bürger, Science, 2007
  56. 56. Carlo Emilio Bonferroni 1892 - 1960
  57. 57. 2 Is there an optimal approach for recovering low-frequency variability from climate-sensitive tree rings?
  58. 58. 20-day weather simulation from NASA’s GEOS-5 model
  59. 59. DECADALCLIMATE VARIABILITY
  60. 60. Benoit Mandelbrot March 2007
  61. 61. “ We shall speak of “Joseph-wild” behavior when the we est decade within a century includes an extraordinary “term” of wet years. ”
  62. 62. Central Pacific Coast
  63. 63. Ault and St. George, Journal of Climate, 2010
  64. 64. Ault and St. George, Journal of Climate, 2010
  65. 65. “ The decadal time scale offers a critical bridge for informing adaptation strategies as ” climate varies and changes. Meehl et al., BAMS, 2009
  66. 66. ~10 yr~100 yr = variability low ‘n’ observations
  67. 67. “ ... 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
  68. 68. Source: Dan Griffin
  69. 69. DIFIEDM O SINGULAR SPECTRUM ANALYSIS
  70. 70. x(t) y(t) tEOFsreconstructed sibling components components
  71. 71. really not that decadal decadalSource: St. George and Ault, Journal of Geophysical Research - Atmospheres, 2011
  72. 72. How well does this approach characterize decadal variability?Ault and St. George, Journal of Climate, 2010
  73. 73. 3 Do climate-sensitive trees (and other proxies) transform climate signals in predictable ways?
  74. 74. WATERhigh growth reduced cell division flooding reduced cell expansion anoxic conditions C02 starvationlow growth dry wet
  75. 75. ∆S
  76. 76. “ Discharge or lake records ‘‘have a tendency to exhibit more pronounced and smoother cycles’’ than precipitation because of storage. ” Vit Klemeš
  77. 77. Do proxiesPUMP UP low-frequency signals?
  78. 78. Source: Jansen Cardy Sarah Truebe University of Arizona
  79. 79. Truebe et al., IOP Conference Series : Earth and Environmental Science, 2010
  80. 80. WATERhigh growth reduced cell division flooding reduced cell expansion anoxic conditions C02 starvationlow growth dry wet
  81. 81. “ [L]inear empirical–statistical analyses alone cannot be used to prove a physical or biological mechanism for variability or ” change in the climate-tree growth relationship. Anchukaitis et al., Geophysical Research Le ers, 2007
  82. 82. Even a simple cambial model can reproduce the main features in real tree-ring data from RussiaSource: Evans et al., Journal of Geophysical Research, 2006
  83. 83. Pinus spp.Source: Paul Schulte
  84. 84. CONTEMPORARY ISSUES IN THE STUDY OF ANCIENT CLIMATESCLIMATE SCIENCE, STATISTICS AND THE COMPUTATIONAL SCIENCES READING GROUP APRIL 2012
  85. 85. “ Tree-ring analysis is one of the most powerful tools available for the study of environmental change and the identification of fundamental relationships ” between tree growth and climate. Ed Cook and Neil Pederson Lamont-Doherty Earth Observatory
  86. 86. Toby Ault National Corporation for Atmospheric Research

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