Calibration and temperature correction of heat dissipation matric potential sensors
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Abstract
This paper describes how heat dissipation sensors, used to measure soil water matric potential, were analyzed to develop a normalized calibration equation and a temperature correction method. Inference of soil matric potential depends on a correlation between the variable thermal conductance of the sensor's porous ceramic and matric potential. Although this correlation varies among sensors, we demonstrate a normalizing procedure that produces a single calibration relationship. Using sensors from three sources and different calibration methods, the normalized calibration resulted in a mean absolute error of 23% over a matric potential range of −0.01 to −35 MPa. Because the thermal conductivity of variably saturated porous media is temperature dependent, a temperature correction is required for application of heat dissipation sensors in field soils. A temperature correction procedure is outlined that reduces temperature dependent errors by 10 times, which reduces the matric potential measurement errors by more than 30%. The temperature dependence is well described by a thermal conductivity model that allows for the correction of measurements at any temperature to measurements at the calibration temperature.
| Publication type | Article |
|---|---|
| Publication Subtype | Journal Article |
| Title | Calibration and temperature correction of heat dissipation matric potential sensors |
| Series title | Soil Science Society of America Journal |
| DOI | 10.2136/sssaj2002.1439 |
| Volume | 66 |
| Issue | 5 |
| Year Published | 2002 |
| Language | English |
| Publisher | American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America |
| Contributing office(s) | California Water Science Center |
| Description | 7 p. |
| First page | 1439 |
| Last page | 1445 |