Which statement best defines an atmospheric inversion?

Which statement best defines an atmospheric inversion?

• A. Ambient air temperature is warmer near the ground than at higher elevations.
• B. Ambient air temperature is cooler near the ground than at higher elevations.
• C. The lapse rate is equal to the dry adiabatic rate.
• D. The plume remains buoyant regardless of the temperature gradient.

Answer: (B)

An atmospheric inversion is when temperature increases with height, so the air near the ground is cooler than the air above. The statement describing cooler temperatures at the surface and warmer air higher up matches that condition exactly, because it shows an upward increase in temperature rather than the usual cooling with height. Inversions create a stable layer that suppresses vertical mixing, which can trap pollutants and affect how plumes rise. The other ideas describe different scenarios: a normal lapse rate where it gets cooler with height, a lapse rate tied to the dry adiabatic rate (not about the temperature profile with height), or a plume that stays buoyant regardless of the vertical temperature gradient (which ignores how inversions can blunt buoyancy and confinement).

An atmospheric inversion is when temperature increases with height, so the air near the ground is cooler than the air above. The statement describing cooler temperatures at the surface and warmer air higher up matches that condition exactly, because it shows an upward increase in temperature rather than the usual cooling with height. Inversions create a stable layer that suppresses vertical mixing, which can trap pollutants and affect how plumes rise. The other ideas describe different scenarios: a normal lapse rate where it gets cooler with height, a lapse rate tied to the dry adiabatic rate (not about the temperature profile with height), or a plume that stays buoyant regardless of the vertical temperature gradient (which ignores how inversions can blunt buoyancy and confinement).