Calibration of a TDR probe for low soil water content measurements
| Autor: | Olga Alokhina, Wojciech Skierucha, Andrzej Wilczek |
|---|---|
| Rok vydání: | 2008 |
| Předmět: |
Materials science
Observational error Metals and Alloys Analytical chemistry Soil science Condensed Matter Physics Surfaces Coatings and Films Electronic Optical and Magnetic Materials Soil water Content (measure theory) Calibration Range (statistics) Time domain Electrical and Electronic Engineering Reflectometry Instrumentation Water content |
| Zdroj: | Sensors and Actuators A: Physical. 147:544-552 |
| ISSN: | 0924-4247 |
| DOI: | 10.1016/j.sna.2008.06.015 |
| Popis: | Time domain reflectometry (TDR) probes are increasingly used for field and laboratory estimation of soil water content. Usual calibration of TDR probes for the determination of soil water content uses two media: air for low and water for high values of dielectric permittivity, although the measured range of dielectric permittivity in soil is much smaller as compared to the range implied by the calibration media. The use of air for calibration of short TDR probes gives calibration errors due to overlapping incident and reflected pulses in the reflectogram, which result in their relative shift in time. This phenomenon, named the convolution effect, can be avoided by the application of selected calibration media. The presented approach minimizes of dielectric permittivity measurement errors by choosing the calibration media with dielectric permittivity values close to the limits of the measurement range and the possibility to use TDR probes of various lengths. The comparison of errors of TDR apparent dielectric permittivity measurement in three sandy soils, based on the probe calibrations in various media, is also presented. |
| Databáze: | OpenAIRE |
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