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Chapter 5: Interpreting High-Resolution Proxy Climate Data
climate data) that are annually resolved and that capture decadal-to-century
timescale variability, represent an essential basis for comparison with relatively short modern climate records which are rarely Ion ger than a hundred
years.
When assessing the value of proxy climate data, we should consider a
number of general questions:
• How well can the evidence be dated?
- Is it continuous or erratic?
- Is the resolution seasonal, annual, millennial, etc.?
• What is the statistical quality of the data?
- Is the series replicated?
- What is the strength of the common signal?
- Wh at is the inherent error?
• What can be deduced from the data?
• What is the nature of climate control - precipitation, temperature, etc.?
Seasonal, annual?
• How strong is the forcing signal and at what timescales?
• Is the full spectrum of the forcing under investigation represented?
• What is the response time?
• What is the spatial representativeness?
These questions are relevant to all forms of proxy data interpretation but
this discussion will address some of them in the context of one particular
proxy source, that of tree rings.
Tree-ring chronologies can provide high-resolution (annual or even seasonal), continuous, relatively-Iong (up to millennial), absolutely-dated, wellreplicated and sensitive (i.e. accurate) indicators of climate variability from
large areas of the globe. This gives tree rings a special status among the various proxy climate data sources. The study of the annual growth of trees and
the consequent assembling of long, continuous chronologies for use in dating
wood (such as in an archaeological context) is called dendrochronology. The
study of the relationships between annual tree growth and climate is called
dendroclimatology.
This chapter attempts to give abrief overview of dendroclimatology, focussing on some basic concepts and statistical techniques which have implications for gauging the value of dendroclimatic reconstructions. For more
detailed general references which provide much discussion on the biological background, methodology and scope of tree-ring-related work, see Fritts
(1976), Hughes et al. (1982), Schweingruber (1988), Cook and Kairiukstis
(1990) and Hughes (1990).
Chapter 5: Interpreting High-Resolution Proxy Climate Data
climate data) that are annually resolved and that capture decadal-to-century
timescale variability, represent an essential basis for comparison with relatively short modern climate records which are rarely Ion ger than a hundred
years.
When assessing the value of proxy climate data, we should consider a
number of general questions:
• How well can the evidence be dated?
- Is it continuous or erratic?
- Is the resolution seasonal, annual, millennial, etc.?
• What is the statistical quality of the data?
- Is the series replicated?
- What is the strength of the common signal?
- Wh at is the inherent error?
• What can be deduced from the data?
• What is the nature of climate control - precipitation, temperature, etc.?
Seasonal, annual?
• How strong is the forcing signal and at what timescales?
• Is the full spectrum of the forcing under investigation represented?
• What is the response time?
• What is the spatial representativeness?
These questions are relevant to all forms of proxy data interpretation but
this discussion will address some of them in the context of one particular
proxy source, that of tree rings.
Tree-ring chronologies can provide high-resolution (annual or even seasonal), continuous, relatively-Iong (up to millennial), absolutely-dated, wellreplicated and sensitive (i.e. accurate) indicators of climate variability from
large areas of the globe. This gives tree rings a special status among the various proxy climate data sources. The study of the annual growth of trees and
the consequent assembling of long, continuous chronologies for use in dating
wood (such as in an archaeological context) is called dendrochronology. The
study of the relationships between annual tree growth and climate is called
dendroclimatology.
This chapter attempts to give abrief overview of dendroclimatology, focussing on some basic concepts and statistical techniques which have implications for gauging the value of dendroclimatic reconstructions. For more
detailed general references which provide much discussion on the biological background, methodology and scope of tree-ring-related work, see Fritts
(1976), Hughes et al. (1982), Schweingruber (1988), Cook and Kairiukstis
(1990) and Hughes (1990).