geoisotherms

例句：

1. 1. The geothermal gradient is a key factor in determining the temperature of the Earth's surface.
   地温梯度是决定地球表面温度的关键因素。
2. 2.The geothermal gradient varies greatly from place to place due to differences in geological structure.
   由于地质结构的差异，地温梯度在各地有很大的差异。
3. 3. Understanding the geothermal gradient is crucial for predicting the distribution of natural resources underground.
   理解地温梯度对于预测地下自然资源的分布至关重要。