Punching Holes in the Sky

Scientists, photographers and amateur cloud watchers have been looking up with wonderment and puzzlement at "hole punch" clouds for decades. Giant, open spaces appear in otherwise continuous cloud cover, presenting beautiful shapes but also an opportunity for scientific investigation. A new paper published last week in Science inquires into how the holes get punched – airplanes are the culprit – and into the potential for the phenomenon's link to increased precipitation around major airports.

"It appears to be a rather widespread effect for aircraft to inadvertently cause some measureable amount of rain or snow as they fly through certain clouds," said lead author Andrew Heymsfield of the National Center for Atmospheric Research, Boulder, Co. "This is not necessarily enough precipitation to affect global climate, but it is likely to be noticeable around major airports in the midlatitudes."

NASA Langley Research Center cloud specialist Patrick Minnis was one of the co-authors on the paper. NASA satellites Aqua, Terra, CALIPSO and CloudSat were used in the analysis. The research was also partly funded by NASA grants.