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Variable seasonal coupling between air and ground temperatures: A simple representation in terms of subsurface thermal diffusivity
Author(s) -
Pollack Henry N.,
Smerdon Jason E.,
van Keken Peter E.
Publication year - 2005
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2005gl023869
Subject(s) - thermal diffusivity , coupling (piping) , environmental science , thermal , variable (mathematics) , precipitation , meteorology , atmospheric sciences , mechanics , thermodynamics , geology , materials science , physics , mathematics , mathematical analysis , metallurgy
The utility of subsurface temperatures as indicators of temperature changes at Earth's surface rests upon an assumption of strong coupling between surface air temperature (SAT) and ground surface temperature (GST). Here we describe a simple representation of this coupling in terms of a variable thermal diffusivity in the upper meter of the subsurface. The variability is tied to daily SAT, precipitation, and snow cover, but does not incorporate the physical details of these and the many other factors that influence the air‐ground interface in many high‐fidelity land‐surface models. Our simple model reduces the difference between observed and modeled temperatures by a factor of 3 to 4 over a model with uniform diffusivity driven only by SAT. This simple representation of air‐ground coupling offers a means of simulating subsurface temperatures using only archived meteorological records and creates the potential for examining the long term character of air‐ground temperature coupling.