Zhong Liu, George Mason University Fairfax, Center for Spatial Information Science and Systems (CSISS), Fairfax, VA, United States, Shimei Pan, University of Maryland Baltimore County, Dept. of Information Systems, Baltimore, MD, United States, Jianwu Wang, University of Maryland Baltimore County, Information Systems, Baltimore, MD, United States, Angela Li, NASA Goddard Space Flight Center, GES DISC, Greenbelt, MD, United States and David J Meyer, NASA Goddard Space Flight Center, Greenbelt, MD, United States