Question

If the ambient lapse rate is higher than the dry adiabatic lapse rate, the atmosphere is

• A. stable
• B. neutral
• C. unstable
• D. strongly stable

Hint:

If ambient lapse rate exceeds DALR, the atmosphere is unstable and promotes strong vertical mixing.

Answer 1

The Correct Option is C

Atmospheric stability depends on the comparison between the ambient lapse rate (actual temperature decrease with height) and the dry adiabatic lapse rate (DALR). Step 1: Understand DALR. DALR = 9.8 °C/km. If a rising air parcel cools slower than the surrounding atmosphere, it becomes warmer and continues to rise → unstable. Step 2: Given condition. Ambient lapse rate>DALR means the atmosphere cools faster with height than an adiabatically rising parcel. Thus, a rising parcel is warmer than the surroundings → buoyant → keeps rising → unstable atmosphere. Therefore, option (C) is correct.
Final Answer: Unstable (C)