Located between about 80 and 700 kilometers (50 and 440 miles) above Earth's surface is the thermosphere, whose lowest part contains the ionosphere. The temperature of the thermosphere increases with height due to absorption of solar radiation within the ionosphere, which is concentrated in the upper thermosphere. There is very little to absorb solar radiation in the mesosphere, and it receives very little heat from below, hence the thermosphere is much warmer. The thermosphere is directly above the mesosphere and below the exosphere. Earth's ionosphere, composed of several regions overlaps with and shares the same space as the thermosphere. The thermosphere is a layer of Earth's atmosphere that is directly above the mesosphere and below the exosphere. Temperatures decrease with increasing height as the ozone layer is left behind and the air thins out with increasing altitude. The lowest portion of the low-pressure mesosphere is heated by the warm air of the upper stratosphere. This heat radiates upward, getting less intense as altitude increases.

Partitioning of layers irrespective height decide the temp. And longwave and insolation decide temp.