The International Cloud Atlas is the official, definitive encyclopedia of clouds. The World Meteorological Organization literally writes the book on weather. Under the United Nations, the WMO has been publishing the atlas since 1896. Until today, which just so happens to be World Meteorological Day, the atlas hadn’t been updated since 1987.
Among others, the update includes Pretor-Pinney’s cloud — asperitas, which means “roughness.” It looks like waves on the underside of the clouds. Now meteorologists all over the world can refer to it and everyone knows what everyone else means. It’s great to be on the same page.
“I’ve actually watched it happen rather than fought for it,” Pretor-Pinney told the Post in a phone interview Thursday. “I threw it out there as an idea to describe this formation which we’d noticed from the photographs sent in from our members around the world.”
Perhaps what’s so great about this story is that without the rise of mobile phone cameras and social media, we never would have known they exist. With increasing frequency, photos of turbulent, ocean-wave-like clouds were shared with meteorologists. People wanted to know what they were but they couldn’t find a name and they didn’t fit any definition in the cloud atlas.
Also thanks to the Internet, the World Meteorological Organization was inundated with news stories and public interest in this cloud type. Cloud appreciators wanted to name this cloud, but people familiar with the bureaucratic nature of the United Nations told Pretor-Pinney, “Don’t hold your breath.”
“At first I think they were irritated,” Pretor-Pinney said, laughing, “then they decided it was high time they did a new edition of the cloud atlas.”
Before this, people would need to contact the WMO itself to purchase the atlas in book format. Even as the Internet was invented and flourished, the cloud atlas was not translated into HTML. Today, you can access and search the cloud database online.
It’s fair to wonder why this matters.
The technical reason is that every weather forecasting and observing organization in the United Nations (e.g. The U.K. Met Office or Australia’s Bureau of Meteorology) must adhere to the accepted terms and descriptions set forth by the WMO. Clouds shouldn’t have different names in different parts of the world.
The other, perhaps more important, reason is human nature.
“Every cloud in the sky is unique,” Pretor-Pinney said. “The whole idea of giving them classifications and putting them in groups — it’s a human thing. We’re imposing our system on the chaos of the sky.”
People have been naming clouds since 1802. Meteorology was a blossoming science and there was a lot of interest in how the weather works. Cumulus, cirrus and stratus were among the clouds first named. In 1897, the cloud atlas was created and meteorologists could finally point to a reference for things they’d been referring to for nearly a century.
More thoughtfully, Pretor-Pinney said it’s a way to make sense of our environment.
“It helps to connect us to our atmosphere,” he mused. “To name something is to know it, in some senses.”