1. Key Laboratory of Wetland and Watershed Research, Ministry of Education, Jiangxi Normal University, Nanchang 330022, P.R. China
2. Departments of Geological and Atmospheric Sciences, Iowa State University, Ames, IA 50011, USA
3. State Key Laboratory of Information Engineering in Surveying, Mapping and Remote Sensing (LIESMARS), Wuhan University, Wuhan 430079, P.R. China