Climatic Inferences from Dendroecological Reconstructions - Dendroclimatology - page 286

Fig. 9.14 Multiple reconstructions of the El Niño/Southern Oscillation (ENSO) show a reduced
occurrence or amplitude during the 1780s-1840s period ( vertical shaded bar ) (Kitzberger et al.
2001 ) . ( a ) La Niña and El Niño events reconstructed from tree-ring chronologies in Patagonia and
central Chile (Villalba 1994 ) . ( b ) Recurrence of moderate to very strong El Niño events recon-
structed from archival documents (Quinn and Neal 1992 ) . ( c ) El Niño recurrence based on years
when d 18 O was > -16‰ (i.e., warm events) in the Quelccaya summit ice core record (Michaelsen
and Thompson 1992 ) . Plots are mean number of events per year based on moving 49-year sums
of all indices. ( d ) Record of ENSO-related central Pacific upwelling based on d 18 O(‰)coral
from Urvina Bay, Galapagos Islands (Dunbar et al . 1994 ; 49-year running mean). In all cases
the horizontal dotted line represents long-term mean values (reprinted from Global Ecology and
Biogeography , permission granted from Wiley-Blackwell)

tree-ring reconstruction of the Pacific Decadal Oscillation (PDO; D'Arrigo et al.
2001 ) was weakly correlated with the second principal component ( r <

0.01). Moreover, an independent tree-ring width reconstruction of the Atlantic
Multidecadal Oscillation (AMO; Gray et al. 2004 ) appeared to be associated with

= 0.17, p