Dendroclimatology from Regional to Continental Scales: Understanding Regional Processes to Reconstruct Large-Scale Climatic Variations Across theWestern Americas - Dendroclimatology - page 183

Box 7.1 Climate signals in Gulf of Alaska tree-ring records
A network of climatically sensitive tree-ring records has been compiled
for the Gulf of Alaska (GOA) region, and the records have been used to
develop time series of temperatures over the past one to two millennia (Box
Fig. 7.1 ) . This region is strongly sensitive to the climatic effects of the
Pacific Decadal Oscillation (PDO), and the GOA chronologies show evidence
for decadal-scale regime shifts, including the noteworthy 1976 transition in
Pacific climate. These records have been linked to sea surface temperature
(SST) variations in the Pacific and have been included in reconstructions of
the PDO (e.g., D'Arrigo et al. 2001 ) . On longer timescales, century to mil-
lennial temperature variations are evident and are linked to glacial changes in
southern Alaska.
Box Fig. 7.1 Map of North Pacific region showing locations of tree-ring sites ( yellow )
used as candidate predictors of the tropical Indo-Pacific climate index (NPI). Sites in red
are those included in the regression model used to reconstruct the NPI. Some dots represent
more than one site (D'Arrigo et al. 2005 )
Analyses of instrumental data demonstrate robust linkages between
decadal-scale North Pacific and tropical Indo-Pacific climatic variability, yet
information on the tropical-high-latitude climate connection is limited prior
to the twentieth century. Gulf of Alaska and western Canadian tree-ring
records were used to reconstruct the December-May North Pacific index
(NPI—an index of the atmospheric circulation related to the Aleutian low-
pressure cell) from 1600 to 1983 (D'Arrigo et al. 2005; Box Fig. 7.2 ) . This
NPI reconstruction shows evidence for the climatic regime shifts seen in the
instrumental NPI data, and for additional events in prior centuries. It correlates
significantly with both instrumental tropical climate indices and a coral-based