New Type of Cloud?

Who says there is nothing new under the sun? - HLG

New Cloud Type Discovered?




June 3, 2009--These choppy clouds over Cedar Rapids, Iowa, in an undated picture could be examples of the first new type of cloud to be recognized since 1951. Or so hopes Gavin Pretor-Pinney, founder of the Cloud Appreciation Society.

The British cloud enthusiast said he began getting photos of "dramatic" and "weird" clouds (including the above) in 2005 that he didn't know how to define.

A few months ago he began preparing to propose the odd formations as a new cloud variety to the UN's World Meteorological Organization, which classifies cloud types.

Pretor-Pinney jokingly calls it the "Jacques Cousteau cloud," after its resemblance to a roiling ocean surface seen from below. But the cloud fan has proposed a "formal," Latin name: Undulus asperatus—roughly, "a very turbulent, violent, chaotic form of undulation," explained Pretor-Pinney, author of the new Cloud Collector's Handbook.

Asked how has such a striking cloud type could go unrecognized, Pretor-Pinney cites its rarity—and the proliferation and portability of digital cameras. "Technology has allowed us to have this new perspective on the sky."



An "asperatus" cloud rolls over New Zealand's South Island in an undated picture.

This apparently new class of clouds is still a mystery. But experts suspect asperatus clouds' choppy undersides may be due to strong winds disturbing previously stable layers of warm and cold air.

Asperatus clouds may spur the first new classification in the World Meteorological Organization's International Cloud Atlas since the 1950s, Gavin Pretor-Pinney said.

Since the last addition to the atlas, the emergence of satellite imagery has pushed meteorologists to take a much broader view on weather and focus less on small-scale cloud formations.

But "the tide is turning back again," in part because the humble cloud is seen as a "wild card" in climate-change prediction, Pretor-Pinney said



A possibly new variety of cloud, the asperatus, coats the sky in Perthshire, Scotland, in an undated picture.

Gavin Pretor-Pinney, who is proposing that asperatus clouds be officially recognized, said that clouds get a "bad rap."

"People complain about … having a cloud hanging over them, compared to someone having a sunny outlook on life," said Pretor-Pinney, founder of the Cloud Appreciation Society.

"To me, clouds are one of the most beautiful parts of nature. … "
—Photograph courtesy Ken Prior




If the asperatus cloud type is classified as a new variety (above, asperatus clouds over Devon, U.K. in an undated picture), it would be the first addition to the World Meteorological Organization's cloud atlas since 1951.

Asperatus's champion, Gavin Pretor-Pinney, author of The Cloud Collector's Handbook, argues for greater appreciation of his subject.

"Even if you live in the middle of the city," he said, "the sky is the last wilderness you can look out on."
—Photograph courtesy Richard Huntington