Definition
The increase in temperature of a parcel of air caused by compression as it descends to lower altitudes, with no heat added from or lost to the surrounding air.
Plain English
When air sinks, the higher pressure below squeezes it, and squeezing air makes it warmer. The warming comes from the compression itself, not from any outside heat source.
Context Anchor
Seen in weather and atmospheric stability discussions, especially when studying rising and sinking air.
Derivation
From the Greek 'adiabatos', meaning 'not to be passed through' — referring to the idea that no heat passes in or out. The temperature change comes entirely from compression, not from heat flowing in from outside.
Why Pilots Care
Affects forecasts of temperature, cloud formation, and density altitude in descending air, which can influence aircraft performance and turbulence encounters.
Analogy
Think of pumping up a bicycle tire. The pump gets warm because the air inside is being compressed. No flame, no heater — just compression making things hotter.
Grounding Statement
Picture a layer of air sinking toward the ground: as outside pressure increases, the air is squeezed and its temperature rises.
Intuition Check
Do not assume heating always means heat was added from something hot. In adiabatic heating, the air warms because it is compressed, not because heat flowed into it.
Example Sentence 1
As the air mass descended the lee side of the mountain range, adiabatic heating warmed it and reduced the relative humidity.
Example Sentence 2
Pilots planning a descent through a stable air mass anticipate adiabatic heating to estimate the temperature at lower altitudes.