1MOE Key Laboratory of Western China's Environmental Systems, College of Earth and Environmental Sciences, Lanzhou University, Lanzhou, 730000, China
2Institute of Archaeological Science, Fudan University, 220 Handan Road, Shanghai, PR China
3School of Biology & Ecology, Climate Change Institute, University of Maine, Orono, ME 04469, USA
4School of Geography Sciences, South China Normal University, Guangzhou 510631, China
5Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, 100101, China
6Department of Earth Sciences, University of Minnesota, Minneapolis, MN 55455, USA