Temperature inversion

In a temperature inversion, the air gets warmer higher up, creating a "lid" that stops vertical air movement and suppresses convection. This disruption in the air's natural circulation can lead to various effects, such as fog formation and weather suppression.

Why temperature inversions happen:

Temperature inversions typically form under conditions like clear skies, calm winds, and rapid cooling of the surface at night. As the surface cools, the air near the ground becomes cooler, while the air above remains warmer. This results in the cooler air being trapped below the warmer air, forming an inversion layer.

Where temperature inversions are relevant:

• Fog formation:
  Temperature inversions are often linked to the development of radiational fog, which forms when the ground cools overnight, causing the air near the surface to reach its dew point. The warmer air above traps this moisture, leading to dense fog, particularly in valleys or low-lying areas.
• Weather suppression:
  Normally, warm air rises, cools, and condenses to form clouds and storms. However, when an inversion is present, the warm air above prevents the rising air from reaching higher altitudes, where it would typically cool and condense. This can suppress storm development and lead to calmer, clearer skies.
• Agricultural impacts:
  In rural areas, especially during spring or fall, temperature inversions can cause frost. The cooler air near the ground gets trapped beneath warmer air higher up, dropping surface temperatures below freezing, which can damage crops, especially in valleys where the cooler air accumulates.

Scope and scale of temperature inversions:

Temperature inversions can vary in size and duration. Some inversions are localized, affecting small areas like valleys, where cooler air gets trapped. These inversions can cause localized issues like frost or fog. Other inversions can cover larger areas, such as entire cities or plains, especially during extended periods of calm, clear weather.

The duration of an inversion can range from a few hours to several days, depending on weather conditions. Inversions can also vary in strength—some may only affect the air near the ground, while others can extend for kilometers, preventing air from mixing and leading to more significant effects, such as extended fog or weather suppression.