1. Research Institute of Petroleum Exploration and Development PetroChina Beijing China
2. Institute of Global Environmental Change Xi'an Jiaotong University Xi'an China
3. Key Laboratory of Cenozoic Geology and Environment Institute of Geology and Geophysics Chinese Academy of Sciences Beijing China
4. Department of Earth Science California State University, Dominguez Hills Carson CA USA
5. Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China
6. Department of Earth and Environmental Sciences University of Minnesota Minneapolis MN USA
7. State Key Laboratory of Loess and Quaternary Geology Institute of Earth Environment Chinese Academy of Sciences Xi'an China