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Solar forcing of Holocene droughts in a stalagmite record from West Virginia in east‐central North America
Author(s) -
Springer Gregory S.,
Rowe Harold D.,
Hardt Ben,
Edwards R. Lawrence,
Cheng Hai
Publication year - 2008
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 - 10.1029/2008gl034971
Subject(s) - stalagmite , holocene , climatology , geology , forcing (mathematics) , solar irradiance , oceanography , paleoclimatology , atmospheric sciences , climate change
Elevated Sr/Ca ratios and δ 13 C values in Holocene‐age stalagmite BCC‐002 from east‐central North America record six centennial‐scale droughts during the last five North Atlantic Ocean ice‐rafted debris (IRD) episodes, previously ascribed to solar irradiance minima. Spectral and cross‐spectral analyses of the multi‐decadal resolution Sr/Ca and δ 13 C time series yield coherent ∼200 and ∼500 years periodicities. The former is consistent with the de Vries solar irradiance cycle. Cross‐spectral analysis of the Sr/Ca and IRD time series yields coherent periodicities of 715‐ and 455‐years, which are harmonics of the 1,450 ± 500 year IRD periodicity. These coherencies corroborate strong visual correlations and provide convincing evidence for solar forcing of east‐central North American droughts and strengthen the case for solar modulation of mid‐continent climates. Moisture transport across North America may have lessened during droughts because of weakened north‐south temperature and pressure gradients caused by cooling of the tropical Pacific and Atlantic Oceans.