class 6, climate modes
TRANSCRIPT
GEOG5426 Climate modes
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Compared to my other classes, I am working:
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Compared to my other classes, I am learning:
DendroclimatologyPRINCIPLES OF
A. E. Douglass University of Arizona
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.”
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The principle of cross-dating
The principle of aggregate tree growth
The principal of ecological amplitude
THE PRINCIPLE OF CROSS-DATINGMatching 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.
Same environmental forcings
Similar growth pa!erns
1900 1910 1920 1930
Two Douglas-fir cores from Eldorado Canyon, CO
Graphic: Jeff Lukas, INSTAAR
THE PRINCIPLE OF CROSS-DATING
1900 1910 1920 1930
Two Douglas-fir cores from Eldorado Canyon, CO
Graphic: Jeff Lukas, INSTAAR
THE PRINCIPLE OF CROSS-DATING
Smith and Lewis, 2006
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.
Rt = At + Ct + δD1t + δD2t + Et
tree growth in year ‘t’
THE PRINCIPLE OF AGGREGATE TREE GROWTH
Rt = At + Ct + δD1t + δD2t + Et
size-related growth trendcaused by physiological aging
THE PRINCIPLE OF AGGREGATE TREE GROWTH
Tree age
Ring width
Rt = At + Ct + δD1t + δD2t + Et
climate during year ‘t’
THE PRINCIPLE OF AGGREGATE TREE GROWTH
THE PRINCIPLE OF AGGREGATE TREE GROWTH
Rt = At + Ct + δD1t + δD2t + Et
disturbance within the forest
Rt = At + Ct + δD1t + δD2t + Et
disturbance from outside the forest
THE PRINCIPLE OF AGGREGATE TREE GROWTH
Rt = At + Ct + δD1t + δD2t + Et
random processesnot accounted by other sources
THE PRINCIPLE OF AGGREGATE TREE GROWTH
Rt = At + Ct + δD1t + δD2t + Et
THE PRINCIPLE OF AGGREGATE TREE GROWTH
THE PRINCIPLE OF ECOLOGICAL AMPLITUDEEcological 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.
Ring-width index
Single-site reconstruction
never trust one tree
Multiple-site reconstruction
Network reconstruction
Rt = At + Ct + δD1t + δD2t + Et
THE PRINCIPLE OF AGGREGATE TREE GROWTH
GEOG5426 Climate modes
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).
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).
(at least 5)>
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?
NARROW AND FOCUSED
NARROW AND FOCUSED
“How has the climate of Australia changed since A.D. 1000?”
OK
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
October 27, 2010The human dimension of past climate change
November 3, 2010Megadrought II / Natural hazards
November 10, 2010Isotope paleoclimatology
November 17, 2010Climate forcings
November 24, 2010Climate models
December 1, 2010Regional climate history I
December 8, 2010Regional climate history II
December 15, 2010No class - Fall meeting, American Geophysical Union
Course schedule (current)
Presentations ➜ Feedback ➜ Papers
OPTIONS
Papers ➜ Feedback ➜ Presentations
OR
By November 3
[Tentative] list of 10 articles related to your region and time period.