Wireless sensor network technology has recently been used for high spatial and temporal
resolution soil water content measurements to facilitate better understanding of hydrological
processes in catchment scale. Its performance strongly depends on the quality of the sensors
and the number of sensor nodes. In the first paper, the newly developed SPADE soil water
content sensor was calibrated using a two-step laboratory-based procedure using dielectric
reference liquids. The sensor accuracy was evaluated in terms of sensor-to-sensor variability
and temperature effect. Using sensor-specific calibration significantly improved the
estimation of apparent dielectric permittivity as compared to using a universal calibration
function. The transferability of the temperature correction function from reference liquids to
soils was successful and has been verified with undisturbed soil samples. A site-specific
petrophysical model (complex refraction index model, CRIM) was used to convert apparent
dielectric permittivity into soil water content using 15 soil samples from the Rollesbroich
catchment, with RMSE values of 0.028, 0.025, and 0.022 cm3cm-3 for 5, 20, and 50 cm,
respectively.
Wei Qu
SPADE soil water stochastic modelling