Table 1.

Observational networks used in this study.

Collection	Network	Full Name	Location	Probe type(s)	Reference(s)
NASMD	AMERIFLUX	AmeriFlux	U.S.	Various Dielectric	Baldocchiet al. 2011
Both	ARM	Dept. of Energy Atmospheric Radiation Measurement	Oklahoma, Kansas	Campbell 229L, SMP1	Bond 2005
Both	AWDN	Automated Weather Data Network	Nebraska	Vitel, ThetaProbe ML2X	Hubbard et al. 1983
NASMD	CHILI	Center for Hurricane Intensity and Landfall Investigation	Alabama	Hydraprobe	Kimball et al. 2010
Both	COSMOS	Cosmic Ray Soil Moisture Observing Station	U.S	Cosmic-ray Probe	Zreda et al. 2012
NASMD	DEOS	Delaware Environmental Observing System	Delaware	Campbell 616L	Legates et al. 2005, 2007
NASMD	ECONET	North Carolina Environment and Climate Observing Network	North Carolina	ThetaProbe	Pan et al. 2012
NASMD	MAWN	Michigan Automated Weather Network	Michigan	Campbell 616	Andresen et al. 2011
NASMD	MAW-MO	Missouri Agricultural Electronic Bulletin Board	Missouri	Campbell 616	Guinan and Travlos 2008
NASMD	NOAAHMT	NOAA Hydrometeorology Testbed Observing Network	U.S.	Campbell 616 & Stevens Hydra Probe	Zamora et al. 2011
NASMD	OK-MESO	Oklahoma Mesonet	Oklahoma	Campbell 229L	Illstonet al. 2008
ISMN	PB0-H20	Xenon PBOH2O	Western U.S.	GPS	Larson et al. 2008
Both	SCAN	USDA Soil Climate Analysis Network	U.S.	Hydraprobe (Analog and digital)	Schaefer et al. 2007
NASMD	SDAWN	South Dakota Automated Weather Data Network	South Dakota	Stevens Hydra Probe	-
Both	SNOTEL	Snowpack Telemetry Network	Western U.S.	Hydraprobe (Analog and digital)	Schaefer and Paetzold 2001
ISMN	SOILSCAPE	SoilSCAPE	U.S.	EC5	Moghaddamet al. 2010
Both	USCRN	NOAA U.S. Climate Reference Network	U.S.	Stevens Hydraprobe II Sdi-12	Bell et al. 2013
ISMN	USDA-ARS	USDA Agricultural Research Service	U.S.	Hydraprobe Analog	Jackson et al. 2010
NASMD	WTX-MESO	West Texas Mesonet	Texas	Campbell 616L	Schroeder et al. 2005