1. State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi’an 710075, China.
2. Institute of Global Environmental Change, Xi’an Jiaotong University, Xi’an 710049, China.
3. Department of Geological Sciences, Brown University, Providence, RI 02912, USA.
4. Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China.
5. Research Institute for Global Change, Japan Agency for Marine-Earth Science and Technology, Kanagawa 236-0001, Japan.