1Earth System Science Interdisciplinary Center, University of Maryland, College Park and Hydrological Sciences Branch, NASA Goddard Space Flight Center, Greenbelt, MD, USA
2USDA-ARS Hydrology and Remote Sensing Laboratory, Beltsville, MD, USA
3Department of Soil Science, University of Wisconsin-Madison, 1525 Observatory Drive, Madison, WI 53706, USA
4Atmospheric Turbulence and Diffusion Division, NOAA, P.O. Box 2456, Oak Ridge, TN 37831, USA