Rate of Geothermal Temperature T_G({\bf r}) change along True Vertical Direction:
| (1) | G_T({\bf r}) = \frac{\partial T_G}{\partial z} |
The common agreement is that
(1) does not account effects of the seasonal/daily temperature variations ( which are only noticeable above Neutral Temperature Layer ).
Away from tectonic plate boundaries: GT = 0.025 ÷ 0.030 °C/m.