Frequency, electrical conductivity and temperature analysis of a low-cost capacitance soil moisture sensor

Kizito, Fred; Campbell, Colin S.; Campbell, Gaylon S.; Cobos, D. R.; Teare, Brody; Carter, B.; Hopmans, Jan W.

doi:10.1016/j.jhydrol.2008.01.021

Cited by 301 publications

(260 citation statements)

References 40 publications

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“…Using the empirical calibration equation of Topp et al (1980) volumetric water content is derived from dielectric permittivity, which in turn results from a 5 point dielectric calibration. The TE sensors (predecessors of 5TE) were excessively tested in soils ranging from 3-100 % sand/0-53 % clay and salt-water solutions of electrical conductivities from 1 to 12 dS m −1 by Kizito et al (2008). They found little probe to probe variability and sufficiently small sensitivity to temperature and electrical conductivity so that one single calibration curve was applicable for all studied conditions.…”

Section: Network Datamentioning

confidence: 99%

A soil moisture and temperature network for SMOS validation in Western Denmark

Bircher

Skou

Jensen

et al. 2012

Hydrol. Earth Syst. Sci.

128

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Abstract. The Soil Moisture and Ocean Salinity Mission (SMOS) acquires surface soil moisture data of global coverage every three days. Product validation for a range of climate and environmental conditions across continents is a crucial step. For this purpose, a soil moisture and soil temperature sensor network was established in the Skjern River Catchment, Denmark. The objectives of this article are to describe a method to implement a network suited for SMOS validation, and to present sample data collected by the network to verify the approach. The design phase included (1) selection of a single SMOS pixel (44 × 44 km), which is representative of the land surface conditions of the catchment and with minimal impact from open water (2) arrangement of three network clusters along the precipitation gradient, and (3) distribution of the stations according to respective fractions of classes representing the prevailing environmental conditions. Overall, measured moisture and temperature patterns could be related to the respective land cover and soil conditions. Texture-dependency of the 0-5 cm soil moisture measurements was demonstrated. Regional differences in 0-5 cm soil moisture, temperature and precipitation between the north-east and south-west were found to be small. A first comparison between the 0-5 cm network averages and the SMOS soil moisture (level 2) product is in range with worldwide validation results, showing comparable trends for SMOS retrieved soil moisture (R 2 of 0.49) as well as initial soil moisture and temperature from ECMWF used in the retrieval algorithm (R 2 of 0.67 and 0.97, respectively). While retrieved/initial SMOS soil moisture indicate significant under-/overestimation of the network data (biases of −0.092/0.057 m 3 m −3 ), the initial temperature is in good agreement (bias of −0.2 • C). Based on these findings, the network performs according to expectations and proves to be well-suited for its purpose. The discrepancies between network and SMOS soil moisture will be subject of subsequent studies.

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Section: Network Datamentioning

confidence: 99%

A soil moisture and temperature network for SMOS validation in Western Denmark

Bircher

Skou

Jensen

et al. 2012

Hydrol. Earth Syst. Sci.

128

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“…This can be explained by the limited measurement range provided by the ECH 2 O-TE sensors. Indeed, after Decagon (2007) and Kizito et al (2008), the ECH 2 O-TE sensor provides accurate measurements in the range of volumetric water content from 0 to 50%. For higher values, more calibrations are required.…”

Section: Discussionmentioning

confidence: 99%

Development of a Large-Scale Infiltration Tank for Determination of the Hydraulic Properties of Expansive Clays

Tang

Cui

et al. 2009

Geotechnical Testing Journal

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A large-scale infiltration tank was developed to study the water transfer in compacted expansive clay. Volumetric water content sensors were buried in a soil column for water content monitoring during infiltration. In addition to water content, soil suction and temperature at various locations and the heave at the soil surface were also monitored. Emphasis was put in minimizing the effect of sensors installation on water transfer and soil deformation. The results obtained for 338 days of infiltration were presented in terms of changes in suction, volumetric water content, temperature, and the soil heave. Based on the recorded data, the performance and limitation of different suction and volumetric water content sensors and the adopted test procedure were analyzed. The recorded data on soil suction and volumetric water content were finally analyzed for determining the unsaturated hydraulic properties of soil, such as the water retention curve and the unsaturated hydraulic conductivity. Note also that the results constitute useful data for further physical analysis or numerical models’ calibration.

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“…Clay has a lower thermal conductivity than sand or silt (Gemant, 1950) and we used a linear relation analogous to the one proposed by Wu & Nofziger (1999): Simultaneously, and at the same depths and Locations, soil water content (θ, m 3 m -3 ) was measured by Echo EC-5 soil moisture sensors (Decagon Devices) (Kizito et al, 2008;Rosenbaum et al, 2010). This instrument uses frequency domain reflectometry technology to obtain volumetric water content, covering the full range of water contents with an accuracy of 0.03 m 3 m -3 and resolution of 0.001 m 3 m -3 .…”

Section: Soil Thermal Diffusivity From Spatiotemporal Datamentioning

confidence: 99%

Soil thermal diffusivity estimated from data of soil temperature and single soil component properties

Lier

Durigon

2013

Rev. Bras. Ciênc. Solo

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SUMMARYUnder field conditions, thermal diffusivity can be estimated from soil temperature data but also from the properties of soil components together with their spatial organization. We aimed to determine soil thermal diffusivity from half-hourly temperature measurements in a Rhodic Kanhapludalf, using three calculation procedures (the amplitude ratio, phase lag and Seemann procedures), as well as from soil component properties, for a comparison of procedures and methods. To determine thermal conductivity for short wave periods (one day), the phase lag method was more reliable than the amplitude ratio or the

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Frequency, electrical conductivity and temperature analysis of a low-cost capacitance soil moisture sensor

Cited by 301 publications

References 40 publications

A soil moisture and temperature network for SMOS validation in Western Denmark

A soil moisture and temperature network for SMOS validation in Western Denmark

Development of a Large-Scale Infiltration Tank for Determination of the Hydraulic Properties of Expansive Clays

Soil thermal diffusivity estimated from data of soil temperature and single soil component properties

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