Calibration and temperature correction of heat dissipation matric potential sensors

Soil Science Society of America Journal
By: , and 

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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
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