1. Department of Civil and Environmental Engineering, University of Virginia, Charlottesville, VA, USA
2. Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA
3. USDA Agricultural Research Service, Beltsville, MD, USA
4. Soil Moisture Company, Boulder, CO, USA
5. Black Swift Technology, Boulder, CO, USA
6. Department of Electrical and Computer Engineering, University of Colorado Boulder, Boulder, CO, USA