Robert F Adler, University of Maryland, College Park, MD, United States, Guojun Gu, ESSIC, University of Maryland College Park, College Park, MD, United States, Jian-Jian Wang, University of Maryland College Park, College Park, MD, United States, George John Huffman, NASA Goddard Space Flight Center, Greenbelt, MD, United States and Ali Behrangi, University of Arizona, Department of Hydrology and Atmospheric Sciences, Tucson, AZ, United States