4 Under some conditions two inversion layers may exist at th

4. Under some conditions, two inversion layers may exist at the same time in the same vertical atmospheric structure. Draw a diagram of temperature versus height that shows one inversion layer between a ground level (i.e., at sea level) and 45 meters, and another aloft, between 110 and 170 meters, while the temperature variations between them approximate equilibrium conditions. (Beers Law)

Solution

Given the right conditions, the normal vertical temperature gradient is inverted such that the air is colder near the surface of the Earth. This can occur when, for example, a warmer, less-dense air mass moves over a cooler, denser air mass. This type of inversion occurs in the vicinity of warm fronts, and also in areas of oceanic upwelling such as along the California coast in the United States. With sufficient humidity in the cooler layer, fog is typically present below the inversion cap. An inversion is also produced whenever radiation from the surface of the earth exceeds the amount of radiation received from the sun, which commonly occurs at night, or during the winter when the angle of the sun is very low in the sky. This effect is virtually confined to land regions as the ocean retains heat far longer. In the polar regions during winter, inversions are nearly always present over land.

When an inversion layer is present, if a sound or explosion occurs at ground level, the sound wave is reflected from the warmer upper layer and returns towards the ground. The sound, therefore, travels much farther than normal. This is noticeable in areas around airports, where the sound of aircraft taking off and landing often can be heard at greater distances around dawn than at other times of day, and inversion thunder which is significantly louder and travels further than when it is produced by lightning strikes under normal conditions

The shock wave from an explosion can be reflected by an inversion layer in much the same way as it bounces off the ground in an air-burst and can cause additional damage as a result. This phenomenon killed three people in the Soviet RDS-37 nuclear test when a building collapsed.