Geoscience Reference
In-Depth Information
Chapter 7
Dendroclimatology from Regional to
Continental Scales: Understanding Regional
Processes to Reconstruct Large-Scale Climatic
Variations Across the Western Americas
Ricardo Villalba, Brian H. Luckman, Jose Boninsegna, Rosanne D. D'Arrigo,
Antonio Lara, Jose Villanueva-Diaz, Mariano Masiokas, Jaime Argollo,
Claudia Soliz, Carlos LeQuesne, David W. Stahle, Fidel Roig, Juan Carlos
Aravena, Malcolm K. Hughes, Gregory Wiles, Gordon Jacoby, Peter
Hartsough, Robert J.S. Wilson, Emma Watson, Edward R. Cook, Julian
Cerano-Paredes, Matthew Therrell, Malcolm Cleaveland, Mariano S.
Morales, Nicholas E. Graham, Jorge Moya, Jeanette Pacajes, Guillermina
Massacchesi, Franco Biondi, Rocio Urrutia, and Guillermo Martinez Pastur
Abstract
Common patterns of climatic variability across the Western Americas
are modulated by tropical and extra-tropical oscillatory modes operating at different
temporal scales. Interannual climatic variations in the tropics and subtropics of the
Western Americas are largely regulated by El Niño-Southern Oscillation (ENSO),
whereas decadal-scale variations are induced by long-term Pacific modes of cli-
mate variability such as the Pacific Decadal Oscillation (PDO). At higher latitudes,
climate variations are dominated by oscillations in the Annular Modes (the Arctic
and Antarctic Oscillations) which show both interannual and longer-scale temporal
oscillations. Here we use a recently-developed network of tree-ring chronologies
to document past climatic variations along the length of the Western Cordilleras.
The local and regional characterization of the relationships between climate and
tree-growth provide the basis to compare climatic variations in temperature- and
precipitation-sensitive records in the Western Americas over the past 3-4 centuries.
Upper-elevation records from tree-ring sites in the Gulf of Alaska and Patagonia
reveal the occurrence of concurrent decade-scale oscillations in temperature dur-
ing the last 400 years modulated by PDO. The most recent fluctuation from the
cold- to the warm-phase of the PDO in the mid 1970s induced marked changes in
