thermal equilibrium

…two systems are each in thermal equilibrium with a third system, the first two systems are in thermal equilibrium with each other. This property makes it meaningful to use thermometers as the “third system” and to define a temperature scale. The first law of thermodynamics, or the law of conservation…

If the permafrost is in thermal equilibrium, the temperature at the level of zero amplitude is generally regarded as the minimum temperature of the permafrost. Below this depth the temperature increases steadily under the influence of heat from Earth’s interior. The temperature of permafrost at the depth of minimum annual…

The delicate thermal equilibrium of permafrost is disrupted when the vegetation, snow cover, or active layer is compacted. The permafrost table is lowered, the active layer is thickened, and considerable ice is melted. This process lowers the surface and provides (in summer) a wetter active layer with…