Active layer distortion of annual air/soil thermal orbits

A straightforward procedure is proposed as a first order, initial approximation for assessing the character of the heat transfer process in the subsurface. Considering monthly averages of air and soil temperatures as a perpendicular superposition of simple harmonic motions, ‘phase‐space’ figures can be generated to permit a rapid qualitative diagnostic of the subsurface thermal regime. It is found that for subsurface conductive regimes the shape of the interface thermal regime. It is found that for subsurface conductive regimes the shape of the interception figures is regular. For sites where an active layer and associated processes are present, the interception figures are highly irregular owing to non‐conducive heat transfer. Implications for the prediction of soil temperatures and determination of climatic changes from geothermal data are discussed in this context.