7.3 Thermal Inversion

temp in troposphere

decreases because pressure decreases and air molecules move farther apart (cold air on top of warm)

inversion

a layer of warm air above a layer of cooler air

* layer of warm air traps cool air beneath it
* pollutants get trapped
* especially in valleys

leads to thermal inversion

* warm fronts/ high pressure
* valleys
* areas of oceanic upwelling (cali)
* when radiation from earth exceeds radiation received from the sun ( during winter night time)
* at poles during the winter, inversions are nearly always present (over land areas only)
* only on land in general, as ocean retains heat

effects

decrease air quality, prevents convection from occurring and will cause any pollutants to be trapped near the surface. Smog formation is an indicator of an inversion causing low air quality

pollution

Pollutants from vehicles, wood burning, area sources, and industry become trapped near the ground during inversions, leading to poor air quality.