The Cloud Appreciation Society says we need to recognise a new cloud type. Alongside cirrus and cumulus clouds, say hello to the asperatus. Society founder Gavin Pretor-Pinney explains.
"In 1802 amateur meteorologist Luke Howard proposed that clouds be classified using Latin terms in the same way as plants and animals. He used cumulus, stratus and cirrus for heaped, layered and wispy clouds."
"Clouds are now described as being one of ten main groups, determined both by their appearance and their altitudes. Most of these groups are then subdivided into a number of possible species."
"The clouds shown here would currently be described as the variety undulatus, which just means "wavelike". But the term is also used to describe those regular, gentle ripples you often see in the cloud layers of a calm sky."
"I argue that the violent, chaotic undulations shown here deserve an additional name of their own: asperatus. This term works to help distinguish these formations from the more everyday examples of undulatus."
"Asperatus comes from the Latin verb aspero, meaning "to roughen up" or "agitate". It was used by the poet Virgil to describe the surface of a choppy sea."
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