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2.2.3 Networks and the Relationship Between Crossdating
and the Emergence of Climate Signal from Networks
of Tree-Ring Data
Whenever possible, chronologies are built for multiple sites in a region, forming
a network of chronologies, each containing records from multiple trees. This pro-
cess provides protection against undue site-specific influences, and increases the
chances of capturing regional-scale climate signals, just as would be the case with
meteorological station data. Chronologies for ecologically comparable sites within a
region typically share many features (Fig. 2.2 ) . Continental- and hemispheric-scale
2.0
1.5
1.0
0.5
0.0
1800
1850
1900
1950
2000
2.0
2.0
1.5
1.5
1.0
1.0
0.5
0.5
0.0
0.0
1810
1820
1830
1840
1850
1970
1980
1990
2000
Year
Year
Fig. 2.2 Common pattern of variability shared by site chronologies over a distance of several
hundred kilometers. Ring-width-based chronologies from 11 locations in the upper basin of the
Colorado River, United States, including that based on the samples from Navajo Canyon shown in
Fig. 2.1 . Each chronology is the mean of multiple detrended ring-width series. ( Top ) Locations of
the chronologies. ( Middle ) The 11 site chronologies for the period AD 1800-2005 shown in gray,
with their mean as the thicker, black line. ( Bottom ) The 11 site chronologies for the periods AD
1810-1850 and 1965-2005. Data provided by David M. Meko; details of chronologies in Meko
et al. ( 2007 )
 
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