Complex imprint of solar variability on tree rings

Abstract

Many studies have investigated the role of solar variability in Holocene climate. Beyond sunspot observations, solar activity can be reconstructed from14C in tree rings. Due to the lack of sub-decadal resolution of14C records, these studies focused on long-term processes. In this study, we use an annually-resolved14C record to examine solar variability (e.g. 11-year Schwabe solar cycle) and its connection to European seasonal climate inferred from tree-ring records during the entire past millennium with spectral and wavelet techniques. The 11-year Schwabe solar cycle shows a significant impact in European moisture-and temperature-sensitive tree-ring records. Complex ’top-down’/ ‘bottom-up’ effects in the strato-tropoatmospheric system are assumed to affect European spring and summer climate with a temporal-shift as evident from observed changes in phase behavior. Significant evidence is also found for the ∼60-and ∼90-year band during the first half of the past millennium.