Title:

Simulating heat transport of harmonic temperature signals in the Earth's shallow subsurface: Lower-boundary sensitivities

Author(s):

Smerdon, Jason E.
Stieglitz, Marc

Date:

2006

Type:

Articles

Department:

Lamont-Doherty Earth Observatory

Volume:

34

Permanent URL:

http://hdl.handle.net/10022/AC:P:10989

Book/Journal Title:

Geophysical Research Letters

Abstract:

We assess the sensitivity of a subsurface thermodynamic model to the depth of its lower-boundary condition. Analytic solutions to the one-dimensional thermal diffusion equation demonstrate that boundary conditions imposed at shallow depths (2–20 m) corrupt the amplitudes and phases of propagating temperature signals. The presented solutions are for: 1) a homogeneous infinite half-space driven by a harmonic surface-temperature boundary condition, and 2) a homogeneous slab with a harmonic surface-temperature boundary condition and zero-flux lower-boundary condition. Differences between the amplitudes and phases of the two solutions range from 0 to almost 100%, depending on depth, frequency and subsurface thermophysical properties. The implications of our results are straightforward: the corruption of subsurface temperatures can affect model assessments of soil microbial activity, vegetation changes, freeze-thaw cycles, and hydrologic dynamics. It is uncertain, however, whether the reported effects will have large enough impacts on land-atmosphere fluxes of water and energy to affect atmospheric simulations.

Subject(s):

Atmospheric sciences
Hydrologic sciences
Geophysics

DOI:

http://dx.doi.org/10.1029/2006GL026816

Item views:

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