1. ICube Laboratory, UMR CNRS–University of Strasbourg, Illkirch Cedex CS 10413, F-67412, France
2. Alterra, Wageningen University and Research, Wageningen 6708 PB, The Netherlands
3. Faculty of Civil Engineering and Earth Sciences, Delft University of Technology, Delft 2628 CN, The Netherlands
4. State Key Laboratory of Remote Sensing Science, Institute of Remote Sensing and Digital Earth, Chinese Academy of Sciences, Beijing 100101, PR China