When does an inversion occur in the atmosphere?

An inversion in the atmosphere occurs when the air temperature increases with altitude, rather than the typical decrease. This situation arises when the surface air is cooler than the air above it, creating a stable layer of warm air that can trap cooler air near the ground.

Typically, environmental conditions that lead to this phenomenon include clear nights where heat radiates away from the surface, cooling the air at ground level, while the air above remains warmer. This setup can trap pollutants and lead to fog or smog conditions, as the cooler air near the surface can’t rise and disperse.

The other options describe scenarios that do not correctly identify the conditions for atmospheric inversions. For instance, stating that surface air is warmer than the air above contradicts the basic premise of inversion layers, which are characterized by cooler air at the surface. Similarly, inversions can occur both during the day and night, not just at nighttime, and while high humidity can influence weather patterns, it is not a direct factor that defines the occurrence of an inversion.