How does temperature change if no heat is lost or gained as a parcel rises?

Question

How does temperature change if no heat is lost or gained as a parcel rises?

Answer 1

well what you said is what we've known as adiabatic temperature change.

The temperature change is not because loosing or gaining heat but the temperature change is due to work done on a parcel of air by the external environment, or work done by a parcel of air on the air that surrounds it. The work in here is The work that is done that is the expansion or compression of air.

Imagine an isolated parcel of air that is moving vertically through the troposphere. We know that air pressure decreases with increasing elevation. As the parcel of air moves upward the pressure exerted on the parcel decreases and the parcel expands in volume as a result. In order to expand (i.e.. do work), the parcel must use its internal energy to do so. As the air expands, the molecules spread out and ultimately collide less with one another. The work of expansion causes the air's temperature to decrease. You might have had personal experience with this kind of cooling if you've let the air out of an automobile or bicycle tire. Air inside the tire is under a great deal of pressure, and as it rushes outside it moves into a lower pressure environment. In so doing, the parcel quickly expands against the outside environment air. By placing your hand in front of the valve stem, you can feel the air cool as it expands. This is called adiabatic cooling.

As air descends through the troposphere it experiences increasing atmospheric pressure. This causes the parcel volume to decrease in size, squeezing the air molecules closer together. In this case, work is being done on the parcel. As the volume shrinks, air molecules bounce off one another more often ricocheting with greater speed. The increase in molecular movement causes an increase in the temperature of the parcel. This process is referred to as adiabatic warming.