Which of the following is not among the conditions ideal for inversion

Which of the following is not among the conditions ideal for inversion of temperature?

A long winter night
Clear skies
Still air
Low air pressure near the ground surface
This question was previously asked in
UPSC CBI DSP LDCE – 2023
Low air pressure near the ground surface is not an ideal condition for temperature inversion; rather, it is generally associated with conditions that prevent inversion.
Temperature inversion is a meteorological phenomenon where temperature increases with increasing altitude, contrary to the usual decrease. Conditions ideal for inversion are typically associated with stable atmospheric conditions that prevent vertical mixing:
1. **Long Winter Night:** Allows for maximum radiative cooling of the ground surface.
2. **Clear Skies:** Clouds absorb and re-emit outgoing radiation, reducing surface cooling. Clear skies allow for efficient outgoing terrestrial radiation and cooling of the ground and the air directly above it.
3. **Still Air:** Wind facilitates mixing of air layers, which disrupts the formation of an inversion layer. Calm or still air allows cold, dense air to accumulate near the surface.
4. **Snow Cover:** A snow-covered surface is an excellent radiator and reflector, enhancing cooling.
5. **Topography:** Valleys and low-lying areas can trap cold air, leading to strong inversions.

Low air pressure near the ground surface is generally associated with rising air (cyclonic conditions) which promotes mixing and instability, opposing the conditions needed for inversion. High pressure is typically associated with sinking air and stable conditions, which favour inversions.

Surface temperature inversions often occur on clear, calm nights when the ground cools rapidly through radiation. The air in contact with the ground cools more than the air above it, leading to the inversion. Inversions can trap pollutants near the surface, leading to reduced air quality.