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This article presents data on annual deep soil temperatures from 0.3 m (1 ft) through 2.1 m (7 ft) at 0.3 m (1 ft) increments for East Tennessee in both graphical and numerical formats. Also, soil temperature data for seven selected geographical locations in the United States were obtained and analyzed for comparison to Tennessee conditions. Other topics related to soil temperature characteristics for various locations were explored and presented.

Annual soil temperature patterns for East Tennessee were unusually consistent and produced sinusoidal relationships. For each consecutive depth from 0.3 m (1 ft) through 2.1 m (7 ft) there were phase shifts of annual soil temperature patterns and also progressive changes of soil temperatures downscale in winter and upscale in summer. The annual range of temperatures for respective soil depths were of different magnitudes. However, the average annual soil temperatures for all depths were equal in magnitude. Consequently, from year-to-year there was no significant increase or decrease of average annual soil temperature for respective soil depths. Soil temperatures for the seven comparative stations showed results similar to Tennessee. Annual ranges of temperatures for all stations were relatively consistent. Annual temperature cycles for stations from the equatorial to the artic region shows the progressive development of the sinusoidal curve as the descriptive annual soil temperature pattern. From the equator to the artic decreases of soil temperatures occurred which were proportional to the latitudinal distance north of the equator of each station. Monthly average global insolation is presented to which soil temperature is directly related. Analysis of both average earth temperature and groundwater temperature showed a strong relationship of both factors to latitude. Annual deep soil temperature patterns of the northern hemisphere showed pronounced similarities to annual soil temperature patterns of the southern hemisphere.