DANGEROUS POLAR STRATOSPHERIC CLOUDS APPEARING MORE OFTEN WORLDWIDE

The Antarctic Ozone Hole is an annual springtime event 

above Earth's frozen, southernmost continent.

Man-made CFCs, naturally occurring Polar Stratospheric Clouds, and the return of sunlight set off incredible destruction of the protective Ozone Layer.

The video of that, shown above, presents these complicated processes with simple to understand animations..

Record ozone hole may open over Arctic in the spring
Science Magazine-Feb 10, 2016

CLOUDS KNOWN AS NACREOUS OR POLAR STRATOSPHERIC CLOUDS ARE BEING SEEN MORE FREQUENTLY AND OVER WIDER AREAS OF OUR PLANET THAN EVER BEFORE.

THESE CLOUDS POSE A VERY REAL DANGER TO OUR ATMOSPHERE BECAUSE THEIR PRESENCE MEANS THE OZONE LAYER IS BEING DEPLETED FURTHER..

FROM NASA:

Clouds do not normally form in the stratosphere due to its extreme dryness. 
During winter at high latitudes, however, stratospheric temperature sometimes becomes low enough to promote formation of clouds.

Called "Mother of Pearl" by Scandinavians due to their iridescent appearance, these clouds are composed of mixtures of naturally occurring water and nitric acid.  

Chemical reactions that occur on the surface of these clouds result in a remarkable transformation of stratospheric composition. 

Chlorine that is supplied to the stratosphere mainly from industrial sources is converted from relatively unreactive forms to other forms that are highly reactive with ozone, leading to substantial ozone depletion. 

[ANOTHER EXPLANATION AND "THEORY" FROM HARVARD: Generally, the top of the troposphere is too cold to allow water vapor to enter the stratosphere. Clouds typically rise in the troposphere due to convection, but at a certain point, the atmosphere becomes too cold for the clouds to rise anymore because all of the water vapor in them precipitates. This point usually occurs by the top of the troposphere, so very little water vapor enters the stratosphere.]

It is a great irony that these beautiful clouds participate in a chain of events that results in the depletion of stratospheric ozone by man-made chlorine.


FROM THE GUARDIAN, U.K.

The most beautiful clouds of all were once only commonly visible to those at the highest latitudes, such as Mawson station, in Antarctica.

 Now, across much of Britain, we too can watch the legacy of our troubled relationship with the atmosphere played out in glorious, mesmerising Technicolor.

Though nacreous clouds are officially known as "polar stratospheric clouds", they are now common over Scotland, and have been observed as far south as the Midlands.

 Lower average winter temperatures in the upper atmosphere might explain why nacreous clouds seem to be appearing with increased frequency and distribution.

 More nacreous clouds appear during colder winters, which lead to a greater subsequent depletion of ozone. The general increase in observations of these clouds is considered by some scientists as linked to man's contribution to global warming.

 Since they form much higher than common clouds - at altitudes of between 12 and 15 miles - nacreous clouds are most apparent around sunrise and sunset when their colours stand out against the darkened sky. The stratosphere is extremely dry, compared with the cloud-filled lower atmosphere, so the air needs to be very cold indeed for any ice crystals to be able to form there.
 
Nacreous clouds only appear when stratospheric temperatures are below -83C. 
This happens more frequently during winter in the Antarctic than the Arctic. 

This is why this type of cloud is more commonly observed in the southern hemisphere.
 It is also why the ozone layer is so much more depleted over the south pole, compared with the north pole.

Besides causing beautiful opalescent colours, nacreous clouds' tiny ice crystals also act to encourage chemical reactions between ozone and the chlorine and bromine that we have introduced into the atmosphere by our use of substances such as chlorofluorocarbons (CFCs) in aerosols and fridge mechanisms. 

Without the presence of stratospheric clouds, reactions leading to the destruction of the ozone layer are negligible.
The nacreous cloud's ice particles behave as nuclei on to which the ozone breakdown can take place.

THE U.K. WAS STARTLED THE FIRST WEEK IN FEBRUARY BY SO MANY OF THESE CLOUDS APPEARING IN THEIR SKIES. 
WHOEVER WROTE THAT ARTICLE CALLED THESE CLOUDS "HARMLESS"...SAID IT WAS A "RARE TREAT" TO SEE THEM....
JOURNALISM ISN'T WHAT IT USED TO BE.

THERE IS A NICE GALLERY OF THOSE <HERE>.


THERE WAS ALSO A LOT OF THEM OVER THE NETHERLANDS THIS MONTH.
AND SCANDINAVIA AND CANADA AND CHINA AND RUSSIA AND......