During a moist adiabatic ascent, why does the parcel cool more slowly than a dry parcel?

Study for the METRO (Meteorology) – VT-10 Test. Enhance your knowledge with flashcards and multiple choice questions, each with hints and explanations. Get ready for your exam today!

Multiple Choice

During a moist adiabatic ascent, why does the parcel cool more slowly than a dry parcel?

When a moist air parcel rises, it expands and cools. If the air is moist, it quickly becomes saturated and water vapor condenses. The condensation releases latent heat inside the parcel, which offsets part of the cooling caused by expansion. Because this internal heat release reduces the net cooling, the temperature of the moist parcel falls more slowly with height than a dry parcel. This is why the moist adiabatic lapse rate is smaller than the dry adiabatic lapse rate. Condensation is the key process enabling the latent heat release; there’s no external heat gain, and the idea that there’s condensation is what makes the moist parcel slow its cooling compared to the dry case.

When a moist air parcel rises, it expands and cools. If the air is moist, it quickly becomes saturated and water vapor condenses. The condensation releases latent heat inside the parcel, which offsets part of the cooling caused by expansion. Because this internal heat release reduces the net cooling, the temperature of the moist parcel falls more slowly with height than a dry parcel. This is why the moist adiabatic lapse rate is smaller than the dry adiabatic lapse rate. Condensation is the key process enabling the latent heat release; there’s no external heat gain, and the idea that there’s condensation is what makes the moist parcel slow its cooling compared to the dry case.

More practice questions