Interesting paper from Xhao & Feng finds strong coherence of De Vries 208 year millennial solar variation with temperature in Antarctica. Also finds incoherence between CO2 and temperature.
Fig. 2.
(a) Squared wavelet coherence between the SSN and T time series. The thick black contours indicate the 95% confidence level against red noise. Black arrows represent phase angles of the cross wavelet (with in-phase pointing right, anti-phase pointing left, SSN leading T by 90° pointing straight down, and SSN lagging T by 90° pointing straight up). The regions inside COI are removed. (b) The global wavelet coherence (Cg, solid line) and the phase angle strength (Sθ, dashed line) between SSN and T plotted against period. (c) Same as (a) but for the CO2 and T time series. (d) Same as (b) but for the CO2 and Ttime series. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)
Abstract
The solar impact on the Earth’s climate change is a long topic with intense debates. Based on the reconstructed data of solar sunspot number (SSN), the local temperature in Vostok (T), and the atmospheric CO2 concentration data of Dome Concordia, we investigate the periodicities of solar activity, the atmospheric CO2 and local temperature in the inland Antarctica as well as their correlations during the past 11,000 years before AD 1895. We find that the variations of SSN and T have some common periodicities, such as the 208 year (yr), 521 yr, and ~1000 yr cycles. The correlations between SSN and T are strong for some intermittent periodicities. However, the wavelet analysis demonstrates that the relative phase relations between them usually do not hold stable except for the millennium-cycle component. The millennial variation of SSN leads that ofT by 30–40 years, and the anti-phase relation between them keeps stable nearly over the whole 11,000 years of the past. As a contrast, the correlations between CO2 and T are neither strong nor stable. These results indicate that solar activity might have potential influences on the long-term change of Vostok’s local climate during the past 11,000 years








