Updated March 22, 2017 16:00:11

Photo: Asperitas were first spotted in 2006 photographs taken in Iowa. (Cloud Appreciation Society: Christopher Singer)

Things are looking up for cloudspotters.

After eight years of lobbying by the Cloud Appreciation Society (CAS), the chaotic, dramatic asperitas formation will be included in the new edition of the World Meteorological Organisation's (WMO) definitive guide to the skies — the International Cloud Atlas.

Asperitas first came to the attention of the CAS, a group of about 43,000 enthusiasts scattered across the world, in 2006 photographs taken in the US state of Iowa.

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As interest in asperitas gathered steam, the group submitted a proposal for the cloud — which it described as having a "chaotic, turbulent appearance" — to be added to the books in 2008, and they have been pushing for it ever since.

Now — or rather on Thursday, when the new edition is released for World Meteorological Day — their efforts have finally come to fruition.

The original proposal suggested the name "asperatus" but the WMO changed that to "asperitas", the Latin word for "roughness".

But asperitas is not the only cloud that will be added to the new edition. In fact, it is set to be one of 11 newly-classified clouds.

The third volume of the atlas will also be the first digitised version of the guide.

Photo: Asperitas formation spotted at the Lofoten islands in the north of Norway. (Cloud Appreciation Society: Ragnhild M Hansen)

'Global, crowdsourced perspective on the sky'

The WMO, a United Nations body, has not added a new variety of cloud to its books since 1956, with the advent of citizen science partly to thank for the addition of the new classifications.

The CAS's proposal to the WMO was based on photos sent in from its members around the world.

"It is a classic example of citizen science, in which observations by the general public, enabled by the technology of smartphones and the internet, have influenced the development of this most official of classification systems," the CAS said.

An app developed by the CAS called Cloudspotters, which allows users to submit photos of cloud formations to be verified by one of a small team of experts, has generated more than 250,000 submissions.

CAS said it provided them with a "global, crowdsourced perspective on the sky" — a solid body of examples of the asperitas as seen from different parts of the world.

Topics: earth-sciences, science-and-technology, weather, human-interest, united-states, united-kingdom

First posted March 22, 2017 15:52:48