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3 - THE SOUTHERN HEMISPHERE
- Edited by M. K. Hughes, P. M. Kelly, J. R. Pilcher, V. C. LaMarche, Jr.
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- Book:
- Climate from Tree Rings
- Published online:
- 05 October 2010
- Print publication:
- 17 June 1982, pp 78-104
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Summary
INTRODUCTION
The Editors
In Chapters 3 and 4, the current extent of the dendroclimatological data base is reviewed and the prospects for expansion in space and time are assessed. The geographical areas referred to in these two chapters reflect areas of research activity rather than climatically or dendrochronologically distinct regions. The climatologists present at the Second International Workshop on Global Dendroclimatology played an active part in the discussions and research priorities were assessed on both climatological and dendrochronological grounds. This was the first time that the potential users of dendroclimatic data had been directly involved at this early stage of the reconstruction process and it proved of great value. Knowledge of the characteristics of the spatial patterns of climatic variation evident in instrumental records was used to guide sampling strategies, alongside the more commonly used principles of dendrochronology.
Salinger describes the climatology of the Southern Hemisphere. The small land area in the temperate zone and its generally low relief, as well as the presence of the ice-covered continent of Antarctica, promote a vigorous year-round circulation. The strong but eccentric circumpolar vortex of low surface pressure is one manifestation of this. The associated extratropical depressions provide the seasonal or year-round rainfall that supports the forest and woodland vegetation of the southern parts of the continents and New Zealand. This rainfall is modified by rain-shadow effects in eastern New Zealand and Argentina and in interior South Africa and Australia.
5 - CLIMATE RECONSTRUCTIONS
- Edited by M. K. Hughes, P. M. Kelly, J. R. Pilcher, V. C. LaMarche, Jr.
-
- Book:
- Climate from Tree Rings
- Published online:
- 05 October 2010
- Print publication:
- 17 June 1982, pp 159-198
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Summary
INTRODUCTION
The Editors
The aim of dendroclimatology is to extract the climate signal in the annual rings of trees and use it to provide a proxy record of climate for times and places where the instrumental record is absent or inadequate. These proxy records are used to produce reconstructions of one or more climate variables in the time, frequency, and sometimes the spatial domains. Reconstructions from tree rings are of potential value in four main fields. First, they may be used to provide an extended climate data base to be used in the testing of models of climate. Second, they may provide a longer and more representative data base for the calculation of climate and climate-related statistics. Third, they may provide detailed descriptions of climate in distant periods which may be used as analogues of possible future changes in climate. Fourth, they may be used in the verification of other proxy records of climate, including historical (or documentary) data, for pre-instrumental times.
The bases of the methods currently available for the preparation and testing of climate reconstructions from tree rings have been discussed in Chapters 1 and 2 of this book, whilst the existing data base, and the potential for its improvement, has been described in Chapters 3 and 4. In order that the reader may see the potential of dendroclimatology, short accounts of a number of dendroclimatic reconstructions are brought together in this chapter.
1 - DATA ACQUISITION AND PREPARATION
- Edited by M. K. Hughes, P. M. Kelly, J. R. Pilcher, V. C. LaMarche, Jr.
-
- Book:
- Climate from Tree Rings
- Published online:
- 05 October 2010
- Print publication:
- 17 June 1982, pp 1-31
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Summary
INTRODUCTION
The Editors
Where trees form annual growth layers, there exists the likelihood that the characteristics of those layers reflect the conditions under which they were formed. Differences in annual growth layers, which are seen as tree rings, may be parallel in many trees within a region indicating that some common set of external factors is influencing growth. Such similarities in growth variation may be strong and spatially extensive. Where this is true, it is reasonable to assume that the external agents forcing the pattern of variability common to trees in a region relate to climate. There are no other environmental factors likely to act on the same range in the space, time, and frequency domains. It should be possible, therefore, to extract a record of the climate variables recorded in the rings of wood formed in the past. This is the basic assumption of dendroclimatology.
Many tree species in the temperate regions show patterns of common year-to-year variability in one or more measure describing the state of the tree ring. This phenomenon has been exploited by scientists in two main fields: dendrochronology (tree-ring dating of wood found in archaeological, geological, or other contexts) and dendroclimatology (the use of tree rings as proxy climate indicators). Both fields depend heavily on the identification and verification of patterns of common yearto- year variability in many wood samples from a site or region.