Open AccessDepth and seasonal variations in the thermal properties of Antarctic Dry Valley permafrost from temperature time series analysis
Author(s) -
Pringle D. J.,
Dickinson W. W.,
Trodahl H. J.,
Pyne A. R.
Publication year - 2003
Publication title -
journal of geophysical research: solid earth
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2002jb002364
Subject(s) - permafrost , thermal conductivity , geology , thermal diffusivity , thermal , thermistor , range (aeronautics) , atmospheric temperature range , atmospheric sciences , mineralogy , materials science , meteorology , thermodynamics , composite material , physics , oceanography , quantum mechanics
We present the first dedicated study of the thermal properties of perennially frozen, ice‐cemented, subsurface Dry Valley permafrost. From time series analysis of 14 months' temperature measurements, we resolve depth and seasonal variations in the thermal properties at two nearby sites at Table Mountain with different origin, composition, and polygonal ground patterning. We determine apparent thermal diffusivity (ATD) profiles directly from thermistor array measurements at 13.5‐cm‐depth intervals and 4‐hour time intervals in the top 2 m. We treat the system as purely conductive year round due to the cold temperatures and compare the performance of several common analysis schemes with a graphical finite difference method that we present in detail. This comparison is facilitated by one site showing strong depth variations including an abrupt twofold increase in ATD across a sharp compositional boundary. We characterize the composition of the inhomogeneous ground from recovered cores and estimate an ice‐fraction‐dependent heat capacity in the range C = 1.7 ± 0.1 to 1.8 ± 0.1 MJ m −3 °C −1 . We calculate apparent thermal conductivity profiles that correlate very well with the core compositions. The conductivity generally lies in the range 2.5 ± 0.5 W m −1 °C −1 but is as high as 4.1 ± 0.4 W m −1 °C −1 for a quartose Sirius sandstone unit at one site. The seasonal variation in the ATD is consistent with its expected temperature dependence.