What is a "thermal inversion"?

A thermal inversion refers specifically to a meteorological phenomenon where a layer of warm air traps cooler air in the atmosphere, typically near the ground. This situation can lead to various weather effects, including the potential buildup of pollutants and smog because the cooler air, which is often denser and more stagnant, becomes trapped beneath the warmer air layer.

In a normal situation, air temperature generally decreases with altitude. However, during a thermal inversion, this pattern is reversed; the warm air overlays the cooler air, creating a stable atmosphere that inhibits vertical mixing. This can contribute to poor air quality and visibility issues in urban areas, especially in valleys or regions surrounded by mountains.

This concept ties into broader weather dynamics by affecting cloud formation, precipitation patterns, and even local wind systems. Understanding thermal inversions is crucial for meteorologists and environmental scientists as they can significantly influence weather forecasts and air quality assessments.