In July 2011, NASA published an article on "Hole Punch" clouds. The phenomena were observed sometime in the 1940s. A paper published in Science a week before the NASA article identified the "culprit" as airplanes. Furthermore, the paper examined the "potential for the phenomenon's link to increased precipitation around major airports". The research was "partly funded by NASA grants" and one of the co-authors of the paper was NASA Langley Research Center cloud specialist Patrick Minnis. The lead author was Andrew Heymsfield from the National Center for Atmospheric Research located in Boulder, Colorado. The scientists studied various satellite images of clouds with hole punches. They then created a computer model that recreated holes and how these formations evolved. They learned that various aspects of a climbing plane and the level it was flying determined whether it was a hole or a canal dug into the cloud. Part of the examination of the physics of hole punches in specific clouds was