Rate of Geothermal Temperature T_G({\bf r}) change along True Vertical Direction z:
| (1) | {\rm Grad} \, T_G({\bf r}) = \frac{\partial T_G}{\partial z} |
The difference between Geothermal Temperature Gradient (GradTG) and Unbiased Geothermal Temperature Gradient (GradTGN) is that the former accounts for the effects of the seasonal/daily temperature variations, which are only significant above Neutral Temperature Layer.
The most common value of Geothermal Temperature Gradient away from tectonic plate boundaries is: GT = 0.025 ÷ 0.035 °C/m.
See Also
Geology / Geothermal Temperature Field
[ Unbiased Geothermal Temperature Gradient (GradTGN) ] [ Unbiased Geothermal Temperature Profile (TGN) ]