1. Lecturer, School of Hydropower and Information Engineering, Huazhong Univ. of Science and Technology, Wuhan, Hubei 430074, China (corresponding author).
2. Engineer, Bureau of Hydrology, ChangJiang Water Resources Commission, Wuhan 430010, China.
3. Professor, Dept. of Institute of Hydropower and Hydroinformatics, Dalian Univ. of Technology, Dalian 116024, China.