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 from C-14 in tree rings. Due to the lack of sub-decadal resolution of C-14 records, these studies focused on long-term processes. In this study, we use an annually-resolved C-14 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 similar to 60- and similar to 90-year band during the first half of the past millennium.