| Title | Reading the bass line: how well do moisture-sensitive tree rings track decadal variability? |
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| Author | St. George, S ;
Ault, T R |
| Source | American Geophysical Union Fall Meeting 2010, abstracts; PP52A-02, 2010 p. 1  Open Access |
| Links | Online - En ligne
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| Image |  |
| Year | 2010 |
| Alt Series | Natural Resources Canada, Contribution Series 20200317 |
| Publisher | American Geophysical Union |
| Meeting | American Geophysical Union Fall Meeting 2010; San Francisco, CA; US; December 13-17, 2010 |
| Document | Web site |
| Lang. | English |
| Media | on-line; digital |
| File format | html; pdf |
| Program | Climate Change Geoscience Climate Change Impacts and Adaptation for Key Economic and Natural Environment Sectors |
| Released | 2010 12 01 |
| Abstract | Most dendroclimatic studies assess past changes in decadal variability by first reconstructing an annually-resolved target variable, and then applying some form of filter that emphasizes variability
within a specific frequency band. We evaluate the ability of a network of tree-ring records along the central Pacific Coast of the United States (hereafter, the CPC) to estimate the behavior of an exceptionally vigorous decadal pattern in winter
precipitation. The CPC is one of the few regions in North America where precipitation records exhibited strong variability at decadal timescales during the last century. Fewer than one-quarter of all tree-ring chronologies from this region are good
proxies for the decadal pattern, but Monte Carlo analysis demonstrates that the level of similarity observed between the ring-width network and winter precipitation was not likely to occur due to chance. By screening the network to retain those
tree-ring chronologies that are optimal predictors of our decadal target, we produce an estimate of that component that is better than those obtained from either projecting the signal over all records or over some function (either the network's mean
or its leading principal component) that describes tree growth across the entire network. Projecting the pattern over the entire length of the tree-ring chronologies indicated that decadal variability in regional precipitation was most vigorous
during the mid and late-20th century. Between 1650 and 1930, the amplitude of the decadal pattern was relatively weak and the proxy estimates show a limited number of decadal events separated by longer intervals of lower variance. Our results
indicate that strong decadal variability is a relatively new feature of the winter climate of the CPC region, and that this type of behavior has been uncommon for most of the last three and a half centuries. They also provide another example of the
benefits of reconstruction approaches that evaluate the ability of proxy records to track climate variability at specific timescales. |
| GEOSCAN ID | 327016 |
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