Version 3 2021-11-15, 21:43Version 3 2021-11-15, 21:43
Version 2 2021-11-13, 03:10Version 2 2021-11-13, 03:10
Version 1 2021-02-01, 14:53Version 1 2021-02-01, 14:53
journal contribution
posted on 2021-11-15, 21:43authored byS. T. Gray, J. L. Betancourt, C. L. Fastie, Stephen T. Jackson
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 (similar to 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.