photo #9446918

When one of the ten main cloud types, like this Altocumulus, is arranged into a recognisable pattern, we can add to its classification another term, known as a species or variety. When Sam Tolton (Cloud Appreciation Society Member 66,118) spotted this Altocumulus over Shoreham-by-Sea, West Sussex, England, its cloudlets seemed to be arranged in bands radiating out from the horizon. That’s the variety radiatus. The ‘Altocumulus’ in the cloud’s name says it’s a clumpy cloud in the mid-level of the troposphere (the lower atmosphere, where weather happens), while the ‘radiatus’ says it appears to radiate from the distance (due to the effect of perspective): Altocumulus radiatus.We can add terms also to describe the cloud’s extent and whether it has gaps. Sam’s Altocumulus covers most of the sky. We refer to that as the species stratiformis (meaning ’layer-like‘ in Latin). Also, its thick clumps have gaps between them. That’s the variety perlucidus. And so, that’s Altocumulus stratiformis perlucidus radiatus. It’s got a ring to it, hasn’t it?