Design and Early Tests of the Day-1 GPM Combined Precipitation Algorithm: IMERG

George J. Huffman, NASA/GSFC/SSAI, Greenbelt, MD; and D. T. Bolvin, D. Braithwaite, K. Hsu, R. J. Joyce, C. Kidd, S. Sorooshian, P. Xie, and S. H. Yoo