Publication Date:
2022-05-26
Description:
The outrigged thermal probes of a "pogo" marine geothermal probe have been
adapted to measure thermal conductivity in-situ by the continuous-heating line
source technique. The instrumental uncertainty in applying the analytical
theory to a single-probe and double-probe configuration is found to be 3 and 6
percent, respectively. The in-situ outrigged single probe 〈.32 cm dia.) is
essentially a scaled-up version of the needle probe (.08 cm dia.). The main
advantage of the outrigged probe over a larger radius probe 〈e.g., violin-bow
probe) is that for short-time temperatures (〈2 min.), simple approximations
to the exact solution for a perfectly conducting cylindrical probe are
achieved. The continuous-heating compares favorably with the pulse-heating
technique, the latter being more energy efficient.
The continuous-heating method applied to the thin outrigged probe allows
for accurate equilibrium in-situ temperature and thermal conductivity
estimates in less than 15 minutes of recording time. The technique has been
applied to several hundred marine heat flow stations. Comparison of in-situ
measurements to needle probe measurements made on nearby piston cores indicate
agreement to within 5%. The conductivity profiles of the in-situ data and
core data show that the piston coring process frequently does not retrieve the
upper meter of surficial sediment.
Description:
Support was provided by the U. S. National Science Foundation under
grant Nos. OCE-8025181, OCE-8117886, and OCE-8409170.
Keywords:
Ocean temperature
;
Terrestrial heat flow
Repository Name:
Woods Hole Open Access Server
Type:
Technical Report
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