Ground surface temperature reconstructions: Using in situ estimates for thermal conductivity acquired with a fiber-optic distributed thermal perturbation sensor
Publication Year
2008
Type
Journal Article
Abstract
We have developed a borehole methodology to estimate formation thermal conductivity in situ with a spatial resolution of one meter. In parallel with a fiber-optic distributed temperature sensor (DTS), a resistance heater is deployed to create a controlled thermal perturbation. The transient thermal data is inverted to estimate the formation s thermal conductivity. We refer to this instrumentation as a Distributed Thermal Perturbation Sensor (DTPS), given the distributed nature of the DTS measurement technology. The DTPS was deployed in permafrost at the High Lake Project Site (67°22′N, 110°50′W), Nunavut, Canada. Based on DTPS data, a thermal conductivity profile was estimated along the length of a wellbore. Using the thermal conductivity profile, the baseline geothermal profile was then inverted to estimate a ground surface temperature history (GSTH) for the High Lake region. The GSTH exhibits a 100-year long warming trend, with a presentday ground surface temperature increase of 3.0 ± 0.8°C over the long-term average. Copyright 2008 by the American Geophysical Union.
Keywords
Atmospheric temperature,
Boreholes,
Electronic medical equipment,
Fiber optics,
Perturbation techniques,
Sensor networks,
Sensors,
Surface properties,
Technology transfer,
Thermal conductivity,
Thermal insulating materials,
Thermoanalysis,
Thermodynamic properties,
Bore hole,
Distributed temperature sensors,
Ground surface temperature,
In-situ,
Measurement technologies,
Project sites,
Spatial resolution SR),
Well bores,
Thermoelectricity,
borehole logging,
estimation method,
fiber optics,
permafrost,
sensor,
spatial resolution,
surface temperature,
thermal conductivity,
Canada,
North America,
Nunavut
Journal
Geophysical Research Letters
Volume
35