1. College of Urban and Environmental Sciences, Northwest University, Xi’an 710127, China
2. Shaanxi Key Laboratory of Earth Surface System and Environmental Carrying Capacity, Xi’an 710127, China
3. Key Laboratory of Watershed Geographic Sciences, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China
4. Analytical Applications Center, Shimadzu (China) Co., Ltd., Xi’an 710127, China