1. a Shapotou Desert Experimental Research Station, Cold & Arid Regions Environmental & Engineering Research Institute, Chinese Academy of Sciences, 260 West Donggang Road, Lanzhou 730000, China.
2. b Department of Water Resources Engineering, Lund University, S-22100 Lund, Sweden.
3. c Shapotou Desert Experimental Research Station, Cold & Arid Regions Environmental & Engineering Research Institute, Chinese Academy of Sciences, 260 West Donggang Road, Lanzhou 730000, China.
4. d Shapotou Desert Experimental Research Station, Cold & Arid Regions Environmental & Engineering Research Institute, Chinese Academy of Sciences, 260 West Donggang Road, Lanzhou 730000, China.