Clouds and the ozone hole
Polar Stratospheric Clouds - what are they?

Recall what is needed for a cloud to form:

• water vapor
• cool temperatures
• low air pressure
• a nucleating agent for the water to condense on

The same applies 12 to 24 km above the South Pole, where temperatures drop to -100 F in the winter. In these conditions, clouds, called polar stratospheric clouds, (PSC's), form in the stratosphere during the long night of the polar winter. They play an important role in the ozone hole that forms over Antarctica during the Austral spring (or the Northern Hemisphere Fall). Below are two interesting photos of these unique clouds.

Next page   -> What's the connection with the ozone hole?

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