American Geophysical Union Become an AGU Member
Subscribe to AGU Journals		 AGU Home AGU Publications

Read Full Article (file size: 293613 bytes)    Cited by

GEOPHYSICAL RESEARCH LETTERS, VOL. 30, NO. 6, 1316, doi:10.1029/2002GL016154, 2003

Patterns and sources of multidecadal oscillations in drought-sensitive tree-ring records from the central and southern Rocky Mountains

Stephen T. Gray

Department of Botany, University of Wyoming, Laramie, Wyoming, USA


Julio L. Betancourt

Desert Laboratory, U.S. Geological Survey, Tucson, Arizona, USA


Christopher L. Fastie

Department of Biology, Middlebury College, Middlebury, Vermont, USA


Stephen T. Jackson

Department of Botany, University of Wyoming, Laramie, Wyoming, USA


Abstract

Tree-ring records spanning the past seven centuries from the central and southern Rocky Mountains were studied using wavelet analysis to examine multidecadal (>30–70 yr) patterns of drought variation. Fifteen tree-ring series were grouped into five regional composite chronologies based on shared low-frequency behavior. Strong multidecadal phasing of moisture variation was present in all regions during the late 16th century megadrought. Oscillatory modes in the 30–70 yr domain persisted until the mid-19th century in two regions, and wet-dry cycles were apparently synchronous at some sites until the 1950s drought. The 16th/17th century pattern of severe multidecadal drought followed by decades of wet conditions resembles the 1950s drought and post-1976 wet period. The 16th century megadrought, which may have resulted from coupling of a decadal (∼20–30 yr) Pacific cool phase with a multidecadal warm phase in the North Atlantic, marked a substantial reorganization of climate in the Rocky Mountain region.

Published 26 March 2003.

Index Terms: 1812 Hydrology: Drought; 1833 Hydrology: Hydroclimatology; 1854 Hydrology: Precipitation (3354); 9350 Information Related to Geographic Region: North America.

Read Full Article (file size: 293613 bytes)    Cited by

Citation: Gray, S. T., J. L. Betancourt, C. L. Fastie, and S. T. Jackson (2003), Patterns and sources of multidecadal oscillations in drought-sensitive tree-ring records from the central and southern Rocky Mountains, Geophys. Res. Lett., 30(6), 1316, doi:10.1029/2002GL016154.