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NAO influence on sub‐decadal moisture variability over central North America
Author(s) -
Fye Falko K.,
Stahle David W.,
Cook Edward R.,
Cleaveland Malcolm K.
Publication year - 2006
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2006gl026656
Subject(s) - climatology , environmental science , spectral analysis , north atlantic oscillation , moisture , atmospheric sciences , geography , geology , meteorology , physics , quantum mechanics , spectroscopy
A strong statistically significant spectral peak with a frequency of 7–8 years is computed for tree‐ring reconstructed summer PDSI averaged at continental and regional scales over North America for the period 1645–1990. A similar, though non‐significant spectral peak is computed for instrumental summer PDSI averaged over North America for the shorter period from 1900–1990. The winter NAO index (1781–2002) has a very strong spectral signature at this same 7–8 year sub‐decadal frequency and is coherent with summer PDSI across a broad sector of the central U.S. Composite analyses confirm a PDSI response to extremes of the NAO over the central U.S., with drought prevalent during negative extremes, and wetness during positive extremes. The winter NAO index leads summer PDSI and a contingency table analysis indicates that extrema in the winter NAO index may have modest forecast value for the following spring‐summer moisture regimes over the central U.S.