7.3 Thermal Inversion

what happens during a thermal inversion?

the normal temperature gradient in the atmosphere is altered as the air temperature at the earth’s surface is cooler than the air at higher altitudes

what does thermal inversion do?

it traps pollution close to the ground — especially smog and particulates

what happens to atmospheric temperature when altitude increases?

decreases

what is the temperature pattern for thermal inversion?

cold, warm, cold

why does pollution become concentrated during a thermal inversion?

it cannot rise to a higher altitude and be dispersed.

PART 1: how do thermal inversions form (during day)?

1. during day, energy from sun heats up earth’s surface.

2. heat slowly released from land + warm air rises (low density)

3. as it rises, warm air cools + becomes more dense

4. falls back towards ground

5. displaces warm air closer to ground —? generate convection motion

PART 2: how do thermal inversions form (during night)?

1. with no sunlight to heat earth’s surface, ground is cooled

2. ground takes heat from air close to it -> cool air closet to ground

3. ground layer is cooler than air above it

what are other possible inversions?

turbulence, frontal inversions, subsidence