What term do we use for the lowest layer of the atmosphere?
The troposphere is the lowest layer of Earth's atmosphere. It extends from Earth's surface to an average height of about , although this altitude varies from about at the geographic poles to at the Equator, with some variation due to weather. The troposphere is bounded above by the tropopause, a boundary marked in most places by a temperature inversion (i.e. a layer of relatively warm air above a colder one), and in others by a zone which is isothermal with height.
What term do we use for the lowest principal layer of the atmosphere?
troposphere
Atmosphere of Earth
No context provided
What term do we use for the lowest secondary layer of the atmosphere?
planetary boundary layer
Atmosphere of Earth
https://en.wikipedia.org/wiki/Atmosphere%20of%20Earth
Within the five principal layers above, which are largely determined by temperature, several secondary layers may be distinguished by other properties: The planetary boundary layer is the part of the troposphere that is closest to Earth's surface and is directly affected by it, mainly through turbulent diffusion.
Atmosphere of Earth Other layers
The troposphere is the lowest layer of Earth's atmosphere. It extends from Earth's surface to an average height of about , although this altitude varies from about at the geographic poles to at the Equator, with some variation due to weather. The planetary boundary layer is the part of the troposphere that is closest to Earth's surface and is directly affected by it, mainly through turbulent diffusion.