How do polar stratospheric clouds contribute to the formation of the Antarctic ozone hole?

The very low winter temperatures in the Antarctic stratosphere cause polar stratospheric clouds (PSCs) to form. Special reactions that occur on PSCs, combined with the isolation of polar stratospheric air in the polar vortex, allow chlorine and bromine reactions to produce the ozone hole in Antarctic springtime.

Why are polar stratospheric clouds harmful?

During the return of spring sunlight these radicals destroy many ozone molecules in a series of chain reactions. Cloud formation is doubly harmful because it also removes from the stratosphere gaseous nitric acid that would otherwise combine with ClO to form less reactive forms of chlorine.

How polar vortex causes ozone depletion?

During winters, the polar vortex at the North Pole expands, sending cold air southward. An ozone hole is the thinning of the ozone layer boosted in size by colder temperatures. As the temperatures high up in the stratosphere starts to rise, ozone depletion slows, the polar vortex weakens and breaks down.

Which clouds cause damage to the ozone layer?

A recent study suggests that highly reactive chlorine and bromine molecules ejected by cumulonimbus clouds are punching holes in the ozone layer over the United States. Ozone absorbs UV radiation from the sun that damages the structure of DNA.

How polar stratospheric clouds are formed?

PSCs are clouds that form when water vapor enters the stratosphere and when temperatures are cold enough for water vapor to condense there. During the winter, the high latitudes receive very little to no solar radiation, so temperatures drop significantly during this period, known as polar night.

What are polar stratospheric clouds Upsc?

Polar Stratospheric Clouds or nacreous clouds contain water, nitric acid and/or sulfuric acid. They are formed mainly during the event of polar vertex in winter; more intense at south pole.

Are polar stratospheric clouds bad?

Casting an iridescent pastel hue across the sky, rare polar stratospheric clouds – also known as nacreous clouds because of their ‘mother of pearl’ color – are one of the most beautiful of all cloud formations. But they are also the most destructive for the ozone layer.

How do polar stratospheric clouds occur?

What causes the stratospheric polar vortex?

The stratospheric polar vortex forms in fall when there is no solar heating in polar regions (and large-scale meridional temperature gradients), strengthens during winter, and then breaks down (and high latitude winds become weak easterlies) as sunlight returns to the polar regions in spring.

How do polar stratospheric clouds form?

Are stratospheric clouds bad?

Some polar stratospheric clouds destroy ozone But at temperatures of around minus-110 degrees, at which these clouds form, ice crystals aren’t always so easy to come by. The limited mixing between the stratosphere and troposphere means very little water vapor makes it aloft.

Do polar stratospheric clouds contain sulfuric acid?

There are two distinct types of Polar Stratospheric Clouds: Type I clouds are composed of nitric acid and water (and sometimes also sulfuric acid), while Type II clouds contain only water ice.