TY - JOUR AU - Kotzé, Pieter B. PY - 2020/07/29 Y2 - 2024/03/29 TI - Identification of solar periodicities in southern African baobab δ13C record JF - South African Journal of Science JA - S. Afr. J. Sci. VL - 116 IS - 7/8 SE - Research Article DO - 10.17159/sajs.2020/6813 UR - https://sajs.co.za/article/view/6813 SP - AB - <p>Spectral analysis using wavelet, Lomb–Scargle and maximum entropy techniques of the proxy rainfall record of northeastern South Africa based on annual carbon isotope (δ<sup>13</sup>C) data obtained from baobab trees for the period 1600 AD – 2000 AD show clear evidence of the presence of characteristic solar periodicities. Solar periodicities that were identified above the 95% confidence level include the ~11-year Schwabe cycle, the ~22-year Hale cycle as well as the 80–110-year Gleissberg cycle. A Morlet wavelet analysis of the δ<sup>13</sup>C data between 1600 AD and 1700 AD shows the effect of the Maunder sunspot minimum on both the Schwabe and Hale cycles during this time.</p><p><strong>Significance:</strong></p><ul><li>A spectral analysis of δ<sup>13</sup>C baobab tree ring data for southern Africa between 1600 AD and 2000 AD is presented. The results show – for the first time – that the δ<sup>13</sup>C time series contains the 11-year Schwabe, 22-year Hale as well as the 80–110-year Gleissberg solar periodicities. In addition, the influence of the Maunder sunspot minimum between ~1650 AD and 1715 AD could also be clearly identified in the δ<sup>13</sup>C data for the first time. These findings are of significant importance to investigations of solar influences on climate variability.</li></ul> ER -