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Class 6, Climate modes

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Class 6, Climate modes

  1. 1. GEOG5426 Climate modes
  2. 2. Compared to my other classes, I am working: 4 3 0 0 0 A lot less Less About average More A lot more
  3. 3. Compared to my other classes, I am learning: 4 2 1 0 0 A lot less Less About average More A lot more
  4. 4. PRINCIPLES OF Dendroclimatology
  5. 5. “ The trees composing the forest rejoice and lament with its successes and failures and carry year by year something of its story in their annual rings.” A. E. Douglass University of Arizona
  6. 6. The principle of cross-dating The principle of aggregate tree growth The principal of ecological amplitude
  7. 7. THE PRINCIPLE OF CROSS-DATING Matching pa erns in tree-ring widths or other ring characteristics (such as ring density) among several trees allow the identification of the exact year in which each ring was formed.
  8. 8. Same environmental forcings Similar growth pa erns
  9. 9. THE PRINCIPLE OF CROSS-DATING 1900 1910 1920 1930 Two Douglas-fir cores from Eldorado Canyon, CO Graphic: Jeff Lukas, INSTAAR
  10. 10. THE PRINCIPLE OF CROSS-DATING 1900 1910 1920 1930 Two Douglas-fir cores from Eldorado Canyon, CO Graphic: Jeff Lukas, INSTAAR
  11. 11. Smith and Lewis, 2006
  12. 12. THE PRINCIPLE OF AGGREGATE TREE GROWTH Any individual tree-growth series can be "decomposed" into a set of environmental signals that affected the tree’s growth through its lifespan.
  13. 13. THE PRINCIPLE OF AGGREGATE TREE GROWTH Rt = At + Ct + δD1t + δD2t + Et tree growth in year ‘t’
  14. 14. THE PRINCIPLE OF AGGREGATE TREE GROWTH Rt = At + Ct + δD1t + δD2t + Et size-related growth trend caused by physiological aging
  15. 15. Ring width Tree age
  16. 16. THE PRINCIPLE OF AGGREGATE TREE GROWTH Rt = At + Ct + δD1t + δD2t + Et climate during year ‘t’
  17. 17. THE PRINCIPLE OF AGGREGATE TREE GROWTH Rt = At + Ct + δD1t + δD2t + Et disturbance within the forest
  18. 18. THE PRINCIPLE OF AGGREGATE TREE GROWTH Rt = At + Ct + δD1t + δD2t + Et disturbance from outside the forest
  19. 19. THE PRINCIPLE OF AGGREGATE TREE GROWTH Rt = At + Ct + δD1t + δD2t + Et random processes not accounted by other sources
  20. 20. THE PRINCIPLE OF AGGREGATE TREE GROWTH Rt = At + Ct + δD1t + δD2t + Et
  21. 21. THE PRINCIPLE OF ECOLOGICAL AMPLITUDE Ecological range limits are o en controlled by climate, and trees growing near the limits of their range are o en more sensitive to climatic fluctuations than similar trees growing under more suitable conditions.
  22. 22. Ring-width index
  23. 23. Single-site reconstruction
  24. 24. never trust one tree
  25. 25. Multiple-site reconstruction
  26. 26. Network reconstruction
  27. 27. THE PRINCIPLE OF AGGREGATE TREE GROWTH Rt = At + Ct + δD1t + δD2t + Et
  28. 28. GEOG5426 Climate modes
  29. 29. Workload A paper, not to exceed 10 pages of text plus figures and references, which reviews the climate history of a single region over a specific time period during the Holocene (e.g., the mid-Holocene, the last 2ka or the last 500 yr).
  30. 30. (at least 5) Workload > A paper, not to exceed 10 pages of text plus figures and references, which reviews the climate history of a single region over a specific time period during the Holocene (e.g., the mid-Holocene, the last 2ka or the last 500 yr).
  31. 31. Focus questions What are the most important features of the modern climate in your region? What proxies are available in your region, over the time interval specified? How are they related to climate? How different were past climates from modern conditions? Why is that important?
  32. 32. NARROW AND FOCUSED
  33. 33. NARROW AND FOCUSED “How has the climate of Australia changed since A.D. 1000?” OK
  34. 34. NARROW AND FOCUSED “How has the climate of Australia changed since A.D. 1000?” OK “Was Western Austria drier during the Medieval Period, compared to today?” Better
  35. 35. Course schedule (current) October 27, 2010 The human dimension of past climate change November 3, 2010 Megadrought II / Natural hazards November 10, 2010 Isotope paleoclimatology November 17, 2010 Climate forcings November 24, 2010 Climate models December 1, 2010 Regional climate history I December 8, 2010 Regional climate history II December 15, 2010 No class - Fall meeting, American Geophysical Union
  36. 36. OPTIONS Presentations ➜ Feedback ➜ Papers OR Papers ➜ Feedback ➜ Presentations
  37. 37. By November 3 [Tentative] list of 10 articles related to your region and time period.

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