Challenges in determining soil moisture and evaporation fluxes using distributed temperature sensing methods

Lagos, Magdalena Sofía; Serna, J. L.; Muñoz, José F.; Suárez, Francisco

doi:10.1016/j.jenvman.2020.110232

Cited by 12 publications

(6 citation statements)

References 58 publications

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“…More details on the method can be found in [ 66 ] and [ 69 ]. Recent works on the applications of active optical fiber DTS focus on the improvement of soil moisture determination by active DTS measurements [ 70 , 71 , 72 ].…”

Section: Seepage Detection Techniques From the Temperature Measurementioning

confidence: 99%

A Review of Measurement Calibration and Interpretation for Seepage Monitoring by Optical Fiber Distributed Temperature Sensors

Ghafoori

Vidmar

Říha

et al. 2020

Sensors

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Seepage flow through embankment dams and their sub-base is a crucial safety concern that can initiate internal erosion of the structure. The thermometric method of seepage monitoring employs the study of heat transfer characteristics in the soils, as the temperature distribution in earth-filled structures can be influenced by the presence of seepage. Thus, continuous temperature measurements can allow detection of seepage flows. With the recent advances in optical fiber temperature sensor technology, accurate and fast temperature measurements, with relatively high spatial resolution, have been made possible using optical fiber distributed temperature sensors (DTSs). As with any sensor system, to obtain a precise temperature, the DTS measurements need to be calibrated. DTS systems automatically calibrate the measurements using an internal thermometer and reference section. Additionally, manual calibration techniques have been developed which are discussed in this paper. The temperature data do not provide any direct information about the seepage, and this requires further processing and analysis. Several methods have been developed to interpret the temperature data for the localization of the seepage and in some cases to estimate the seepage quantity. An efficient DTS application in seepage monitoring strongly depends on the following factors: installation approach, calibration technique, along with temperature data interpretation and post-processing. This paper reviews the different techniques for calibration of DTS measurements as well as the methods of interpretation of the temperature data.

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Section: Seepage Detection Techniques From the Temperature Measurementioning

confidence: 99%

A Review of Measurement Calibration and Interpretation for Seepage Monitoring by Optical Fiber Distributed Temperature Sensors

Ghafoori

Vidmar

Říha

et al. 2020

Sensors

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“…First, the analysis of water stable isotopes by Fritz et al (1981) showed that groundwater is influenced by fractioning processes when the water table is close to the ground surface. Due to the unconfined hydraulic setting of the aquifer, partial groundwater evaporation leads to the formation of salt flats in the southwestern part of the aquifer (Pfeiffer et al 2018, Lagos et al 2020. In this area, Chávez et al (2016) Consequently, the use of the WTF method is reliable for studying ephemeral recharge processes in the drainage and apex areas of the Quebrada de Chacarilla alluvial fan.…”

Section: Abrupt Water Table Variations Posterior To Flood Eventsmentioning

confidence: 99%

Water table variations in Atacama Desert alluvial fans: discussion of “Evidence of short-term groundwater recharge signal propagation from the Andes to the central Atacama Desert: a singular spectrum analysis approach”^*

Viguier

Jourde

Léonardi

et al. 2020

Hydrological Sciences Journal

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Using a statistical approach, Scheihing attempts to demonstrate the direct influence of recharge events in the Precordillera and the Andean Piedmont on water table variations in downstream alluvial fans. The author "unquestionably" discards the existence of ephemeral recharge processes in alluvial fans although they are frequently impacted by major floods. However, the author does not consider previous publications about recharge processes in arid alluvial fans, the hydraulic setting of the Pampa del Tamarugal Aquifer (PTA) and anthropogenic pressure changes in the PTA. Because the sustainable management of groundwater resources in drylands depends on a good understanding of hydrogeological processes, we propose a thorough reinterpretation of the short-and long-term PTA water table variations addressed by the author. In this comment, we illustrate the limits of the sole use of a statistical approach for characterizing both recharge processes and factors controlling the water table variations in the Atacama Desert.

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“…Raman spectra DTS has gained popularity within the Earth sciences because it is a low-cost and simple method for measuring temperature in harsh environments and for sensing temperature gradients over large spatial domains relative to pointwise sensors (Tyler et al, 2009). Applications of DTS in environmental sensing have largely been centered around hydrologic and geologic research (Drusová et al, 2021;Henninges and Masoudi, 2021;Lagos et al, 2020;Selker et al, 2006;Sinnett et al, 2020;Tyler et al, 2009), but there has been increased interest in using DTS for atmospheric measurements over the last decade. Past atmospheric measurements with DTS can generally be categorized into three fields, including surface-layer-to-air interactions (Peltola et al, 2021;Petrides et al, 2011;Thomas et al, 2012), boundary layer dynamics (Egerer et al, 2019;Higgins et al, 2018;Keller et al, 2011;Fritz et al, 2021), and wind measurements (Sayde et al, 2015;van Ramshorst et al, 2020).…”

Section: Introductionmentioning

confidence: 99%

A fiber-optic distributed temperature sensor for continuous in situ profiling up to 2 km beneath constant-altitude scientific balloons

Goetz

Kalnajs²,

Deshler³

et al. 2023

Atmos. Meas. Tech.

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Abstract. A novel fiber-optic distributed temperature sensing instrument, the Fiber-optic Laser Operated Atmospheric Temperature Sensor (FLOATS), was developed for continuous in situ profiling of the atmosphere up to 2 km below constant-altitude scientific balloons. The temperature-sensing system uses a suspended fiber-optic cable and temperature-dependent scattering of pulsed laser light in the Raman regime to retrieve continuous 3 m vertical-resolution profiles at a minimum sampling period of 20 s. FLOATS was designed for operation aboard drifting super-pressure balloons in the tropical tropopause layer at altitudes around 18 km as part of the Stratéole 2 campaign. A short test flight of the system was conducted from Laramie, Wyoming, in January 2021 to check the optical, electrical, and mechanical systems at altitude and to validate a four-reference temperature calibration procedure with a fiber-optic deployment length of 1170 m. During the 4 h flight aboard a vented balloon, FLOATS retrieved temperature profiles during ascent and while at a float altitude of about 19 km. The FLOATS retrievals provided differences of less than 1.0 ∘C compared to a commercial radiosonde aboard the flight payload during ascent. At float altitude, a comparison of optical length and GPS position at the bottom of the fiber-optic revealed little to no curvature in the fiber-optic cable, suggesting that the position of any distributed temperature measurement can be effectively modeled. Comparisons of the distributed temperature retrievals to the reference temperature sensors show strong agreement with root-mean-square-error values less than 0.4 ∘C. The instrument also demonstrated good agreement with nearby meteorological observations and COSMIC-2 satellite profiles. Observations of temperature and wind perturbations compared to the nearby radiosounding profiles provide evidence of inertial gravity wave activity during the test flight. Spectral analysis of the observed temperature perturbations shows that FLOATS is an effective and pioneering tool for the investigation of small-scale gravity waves in the upper troposphere and lower stratosphere.

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Challenges in determining soil moisture and evaporation fluxes using distributed temperature sensing methods

Cited by 12 publications

References 58 publications

A Review of Measurement Calibration and Interpretation for Seepage Monitoring by Optical Fiber Distributed Temperature Sensors

A Review of Measurement Calibration and Interpretation for Seepage Monitoring by Optical Fiber Distributed Temperature Sensors

Water table variations in Atacama Desert alluvial fans: discussion of “Evidence of short-term groundwater recharge signal propagation from the Andes to the central Atacama Desert: a singular spectrum analysis approach”^*

A fiber-optic distributed temperature sensor for continuous in situ profiling up to 2 km beneath constant-altitude scientific balloons

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Challenges in determining soil moisture and evaporation fluxes using distributed temperature sensing methods

Cited by 12 publications

References 58 publications

A Review of Measurement Calibration and Interpretation for Seepage Monitoring by Optical Fiber Distributed Temperature Sensors

A Review of Measurement Calibration and Interpretation for Seepage Monitoring by Optical Fiber Distributed Temperature Sensors

Water table variations in Atacama Desert alluvial fans: discussion of “Evidence of short-term groundwater recharge signal propagation from the Andes to the central Atacama Desert: a singular spectrum analysis approach”*

A fiber-optic distributed temperature sensor for continuous in situ profiling up to 2 km beneath constant-altitude scientific balloons

Contact Info

Product

Resources

About

Water table variations in Atacama Desert alluvial fans: discussion of “Evidence of short-term groundwater recharge signal propagation from the Andes to the central Atacama Desert: a singular spectrum analysis approach”^*