Environmental temperature sensing using Raman spectra DTS fiber‐optic methods

Abstract

[1] Raman spectra distributed temperature sensing (DTS) by fiber-optic cables has recently shown considerable promise for the measuring and monitoring of surface and near-surface hydrologic processes such as groundwater-surface water interaction, borehole circulation, snow hydrology, soil moisture studies, and land surface energy exchanges. DTS systems uniquely provide the opportunity to monitor water, air, and media temperatures in a variety of systems at much higher spatial and temporal frequencies than any previous measurement method. As these instruments were originally designed for fire and pipeline monitoring, their extension to the typical conditions encountered by hydrologists requires a working knowledge of the theory of operation, limitations, and system accuracies, as well as the practical aspects of designing either short-or long-term experiments in remote or challenging terrain. This work focuses on providing the hydrologic user with sufficient knowledge and specifications to allow sound decisions on the application and deployment of DTS systems.

Geothermal point sources identified in a fumarolic ice cave on Erebus volcano, Antarctica using fiber optic distributed temperature sensing

“…Fiber optic distributed temperature sensing (DTS) allows measurement of temperature along a fiber optic cable with spatial resolution as fine as 0.25 m and temporal resolution of 1 Hz. Pioneered by the energy industry, DTS is now an emerging tool in the environmental sciences [Tyler et al, 2009], particularly hydrology [Selker et al, 2006]. A recent investigation in Carlsbad Caverns pioneered the use of DTS in a limestone cave [Dwivedi, 2010], but the technology has yet to be applied to ice caves, glacier caves, or lava tubes.…”

Fiber optic distributed temperature sensing for the determination of air temperature

“…Depending on the type of DTS machine used, temperatures can be measured continuously at sub-meter intervals along cables of more than 5 km, with laboratory accuracies up to 0.01 • C and typical field accuracies of 0.08 • C (van de . A good introduction to DTS principles and environmental applications can be found in Selker et al (2006) and Tyler et al (2009).…”

Estimating interaction between surface water and groundwater in a permafrost region using heat tracing methods

“…The approach we present provides the potential understanding of SW-GW interaction in permafrost regions for a broad range of temporal and spatial scales by extending current knowledge from previous studies based on the point-in time or point-in-15 space measurements (Tyler et al, 2009). Our approach also supports the identification of spatial patterns and temporal distribution of the SW-GW interaction.…”

“…The precision of FO-DTS declines as signal strength decreases (Rose et al, 2013;Tyler et al, 2009). The calibration process can be conducted automatically using the external temperature probe and the built-in program of the DTS equipment, which 15 automatically calibrates the sensor cable in offset and enhanced in attenuation ratio.…”

“…The pioneering of a vertical high-resolution DTS system for hydrologic applications was presented by Selker et al (2006), 5 which has been widely used in observing a broad range of hydrologic processes (Tyler et al, 2009;Liu et al, 2016). FO-DTS temperature measurement is based on the analysis of the temperature dependent Raman spectra backscatter properties of a laser pulse that is applied to, and propagates through, a fiber-optic cable (Selker et al, 2006).…”