The calm layer

The idea

In the stratosphere (12–50 km) the ozone layer absorbs UV and heats the air, so temperature rises with height; the resulting lack of vertical mixing keeps weather confined to the troposphere.

Above the clouds

Clouds and storms stay in the lower sky. The ozone layer lies somewhere above them.

In which layer do you think the ozone layer is found?

• The stratosphere
• The layer that holds the clouds
• The ground layer

Warm on top

Press Next step.

Warm air on top of cool air

In this layer the upper air is warmer than the lower air, so the air does not mix up and down. That keeps weather confined to the troposphere below.

In the stratosphere (12 to 50 km) the ozone layer absorbs UV and heats the air, so temperature rises with height. The resulting lack of vertical mixing keeps weather confined to the troposphere.

Notes

In the stratosphere (12 to 50 km) ozone absorbs UV and heats the air, so temperature rises with height, there is little vertical mixing and weather stays in the troposphere.

Check yourself

Which layer holds the ozone layer?

What happens to temperature with height in the stratosphere?

What keeps weather confined to the troposphere?

The stratosphere extends from 12 km to 50 km. How thick is it?

Answer: 38 km

• The troposphere. The troposphere is the lowest layer, where nearly all weather occurs. The ozone layer is in the stratosphere.
• The stratosphere — correct. Yes!
• The exosphere. The exosphere lies above the stratosphere. The ozone layer is in the stratosphere.
• It falls. Temperature falls with height in the troposphere, not in the stratosphere.
• It stays the same. In the stratosphere temperature rises with height.
• It rises — correct. Yes!
• The rising temperature in the stratosphere calms it, so there is a lack of vertical mixing — correct. Yes!
• Air in the stratosphere mixes up and down quickly. There is a lack of vertical mixing in the stratosphere.
• The stratosphere is colder than the troposphere. In the stratosphere temperature rises with height.