A Robust Heat-Pulse Sensor for Field Water Content Measurement
Abstract
Despite the vast importance of real-time soil water content data, measurement capabilities are limited. Heat-pulse sensors are useful for measuring both thermal properties and water content. Measurements with this sensor do not entail soil-specific calibration and data acquisition requirements are relatively simple. However, use of this sensor in field settings has been limited because the small-diameter probes can deflect during sensor installation. These thin probes are required in order to satisfy the assumptions of the line-source heat transfer model. In this study we present a sensor with large-diameter, rigid probes together with a heat transfer model that accounts for the finite diameter and finite heat capacity of the probes. To determine optimum sensor design, we tested sensors with different probe diameters and lengths in soils of different texture. Results obtained with our new sensor show excellent measurement capabilities and enhanced probe rigidity. We believe the proposed sensor design is well suited for soil moisture measurements in field applications, with an accuracy of about two percent volumetric water content.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2011
- Bibcode:
- 2011AGUFM.H53A1367K
- Keywords:
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- 1866 HYDROLOGY / Soil moisture;
- 1875 HYDROLOGY / Vadose zone;
- 1894 HYDROLOGY / Instruments and techniques: modeling;
- 1895 HYDROLOGY / Instruments and techniques: monitoring