Solar Imprints on Asian Inland Moisture Fluctuations over the Last Millennium

Wednesday, 17 December 2014
Mu Song1, Aifeng Zhou2, Xiaonan Zhang2, Cheng Zhao1,3, Yuxin He1,4, Wenqing Yang5, Weiguo Liu6, Shenghua Li1 and Zhonghui Liu1, (1)The University of Hong Kong, Pok Fu Lam Road, Hong Kong, (2)LZU Lanzhou University, Research School of Arid Environment and Climate Change, Lanzhou, China, (3)CAS Chinese Academy of Sciences, Nanjing Institute of Geography & Limnology, Beijng, China, (4)Zhejiang University, Department of Earth Sciences, Hangzhou, China, (5)USTC University of Science and Technology of China, Institute of Polar Environment, School of Earth and Space Sciences, Hefei, China, (6)CAS Chinese Academy of Sciences, State Key Laboratory of Loess and Quaternary Geology, Beijng, China
Solar irradiance changes are thought to play an important role in natural climate variability. How solar activities affected hydrological changes in westerly-controlled arid central Asia (ACA) on decadal/centennial timescales remains poorly investigated, due to lack of high-quality records. Here we present high-resolution multi-proxy records of lake level changes, and thus effective moisture fluctuations, over the last millennium, from a shoreline sediment core retrieved from Lake Manas, northwestern China. Besides generally confirmed relatively wet conditions during the cool Little Ice Age, records of the geophysical and geochemical indicators, including lightness, calcium counts, and C37 alkenone contents, consistently show substantial and frequent lake level fluctuations, and more importantly, resemble solar irradiance changes. Further, the ~11-year Schwabe cycle, ~70-100-year Gleissberg cycle, and relatively weak spectral power in between, as characters in the sunspot number record, together with the ~200-year Suess-de Vries cycle revealed in the reconstructed total solar irradiance records, are all evident in the higher-resolution calcium and lightness records. Together, our records clearly demonstrate solar imprints on effective moisture fluctuations in ACA over the last millennium, and the occurrence of the Schwabe cycle even during the solar minima.