1 State Key Laboratory of Tibetan Plateau Earth System, Environment and Resources, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China.
2 Department of Earth and Environmental Sciences, Università di Milano-Bicocca, Milano 20126, Italy.
3 Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI 48109-1005.
4 Department of Geosciences, University of Arizona, Tucson, AZ 85721.
5 North China Electric Power University, Beijing 100096, China.