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Do you know your Cirrus from your Cumulus? Or the difference between Stratus and Nimbus?

If you are a keen cloud-spotter then you'll know what we're talking about...

But if you need a little more help to identify what you're seeing in the sky, a new app has been launched to do just that.

It also uses the information to allow NASA to study how clouds affect the Earth's climate.

Charlie and Susanna were joined by Gavin Pretor-Pinney, the creator of the Cloud Spotter app and Richard Allan, who's a climate scientist from the University of Reading.