Assume a warm air parcel at Earth's surface has a temperature of 21 degrees C (70 degrees F) and begins to rise upward. Assume it becomes saturated at 1000 m (3300 ft) altitude, and continues to rise to 2000 m (6600 ft) altitude. What would the approximate temperature of the parcel be at an elevation of 2000 m (6600 ft)?

Question

Quizplus · Accepted Answer

As the parcel rises, it cools at a rate of about 1 degree C per 100 m due to expansion. Therefore, at a height of 1000 m, the temperature would be expected to have decreased to about 21-10= 11 degrees C (70-18= 52 degrees F). At this height, the parcel has become saturated and will cool at a lower rate of about 0.5 degrees C per 100 m due to latent heat release from condensation. Therefore, at a height of 2000 m, the temperature would be expected to have decreased further by 10 degrees C (18 degrees F) due to the lapse rate and an additional 5 degrees C (9 degrees F) due to latent heat release. Therefore, the approximate temperature of the parcel at 2000 m would be around 11-10-5= -4 degrees C (52-18-9= 25 degrees F). However, since the answer choices do not include negative temperatures, the closest choice is D, which is 5 degrees C (41 degrees F).

Assume a Warm Air Parcel at Earth's Surface Has a Temperature