Question

If two parcels of air start at the same temperature at 2000 meters above Earth’s surface, which would end up with a higher temperature, an unsaturated parcel of air at Earth’s surface or a saturated parcel of air 4000 meters above Earth’s surface?

a. An unsaturated parcel of air at Earth’s surface would be warmer, since adiabatic temperature changes are greater for unsaturated than for saturated air, regardless of any temperature difference due to changes in elevation.
b. A saturated parcel of air at 4000 meters above Earth’s surface would be warmer, since air warms as it rises and cools as it descends, regardless of any temperature difference due to saturation.
c. A saturated parcel of air 4000 meters above Earth’s surface would be warmer, since adiabatic temperature changes are greater for saturated than for unsaturated air, regardless of any temperature difference due to changes in elevation.
d. An unsaturated parcel of air at Earth’s surface would be warmer, since air cools as it rises and warms as it descends, regardless of any temperature difference due to saturation.

Answer 1

Option D is correct.

Step-by-step explanation:

The parcel of air at the earth's surface would be much warmer, regardless of any temperature or saturation difference. Why?

It is because of atmospheric pressure and gravity. It is known that air has mass, so this mass is pulled down by gravity. Gravity reaches the maximum strength at sea level, and it decreases as you go up. When air is pulled down the earth's surface, it creates atmospheric pressure. Now, how does this relate to the air's temperature?

At sea level, air particles are being compressed by gravity, and there are more air particles at a single location, which creates friction between those particles, which generates heat. At higher altitudes, the decreasing pressure causes the particles to spread, which generates less friction, which causes a decrease in temperature.